OSAC 2022-S-0032, Best Practice Recommendation for the Chemical 

Processing of Footwear and Tire Impression Evidence

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OSAC 2022-S-0032

Best Practice Recommendation for the 

Chemical Processing of Footwear and 

Tire Impression Evidence

Footwear and Tire Subcommittee

Physics and Pattern Interpretation Scientific Area Committee

Organization of Scientific Area Committees (OSAC) for Forensic Science
OSAC 2022-S-0032, Best Practice Recommendation for the Chemical 

Processing of Footwear and Tire Impression Evidence

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Draft OSAC Proposed Standard

OSAC 2022-S-0032

Best Practice Recommendation for the 

Chemical Processing of Footwear

and Tire Impression Evidence

Prepared by

Footwear and Tire Subcommittee

Version: 1.0

October 2022

Disclaimer:

This OSAC Proposed Standard was written by the Organization of Scientific Area Committees 

(OSAC) for Forensic Science following a process that includes an open comment period. This 

Proposed Standard will be submitted to a standards developing organization and is subject to 

change.

There may be references in an OSAC Proposed Standard to other publications under 

development by OSAC. The information in the Proposed Standard, and underlying concepts and 

methodologies, may be used by the forensic-science community before the completion of such 

companion publications.

Any identification of commercial equipment, instruments, or materials in the Proposed Standard 

is not a recommendation or endorsement by the U.S. Government and does not imply that the 

equipment, instruments, or materials are necessarily the best available for the purpose.

To be placed on the OSAC Registry, certain types of standards first must be reviewed by a 

Scientific and Technical Review Panel (STRP). The STRP process is vital to OSAC’s mission of 

generating and recognizing scientifically sound standards for producing and interpreting forensic 

science results. The STRP shall provide critical and knowledgeable reviews of draft standards or 

of proposed revisions of standards previously published by standards developing organizations 

(SDOs) to ensure that the published methods that practitioners employ are scientifically valid, 

and the resulting claims are trustworthy.

The STRP panel will consist of an independent and diverse panel, including subject matter 

experts, human factors scientists, quality assurance personnel, and legal experts, which will be 
OSAC 2022-S-0032, Best Practice Recommendation for the Chemical 

Processing of Footwear and Tire Impression Evidence

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tasked with evaluating the proposed standard based on a comprehensive list of science-based 

criteria.

For more information about this important process, please visit our website 

at: https://www.nist.gov/topics/organization-scientific-area-committees-forensicscience/scientific-technical-review-panels. 
OSAC 2022-S-0032, Best Practice Recommendation for the Chemical 

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1 Best Practice Recommendation for the Chemical Processing of Footwear 

2 and Tire Impression Evidence

3

4

5

6 Keywords: footwear, tire, impression, evidence, chemical processing

7

8

9

10

11 Abstract: Footwear and tire impressions encountered at a crime scene or on physical evidence 

12 associated with a crime scene may benefit from chemical processing. A variety of chemical 

13 processing techniques and formulas are available to attempt to develop additional details and 

14 contrast in the impression evidence. Techniques and formulations selected for chemical processing

15 are based on the impression matrix, substrate, and other variables.

16
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17 Foreword

18

19 The Footwear & Tire Subcommittee of the Organization of Scientific Area Committees is dedicated to 

20 providing the forensic community with best practices regarding footwear and tire impression 

21 evidence. This document is intended for use by the forensic professional and outlines best practice 

22 recommendations for chemical processing procedures for footwear and tire impressions at crime 

23 scenes and in the forensic laboratory.

24 This document originated as a proposal by the Footwear & Tire Subcommittee of the Organization 

25 of Scientific Area Committees.

26 This is the original issue of this document.
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27 Table of Contents

28 1 Scope ...................................................................................................................................................................................

29 2 Terms and Definitions.................................................................................................................................................

30 3 Recommendations.........................................................................................................................................................

31 3.1. Introduction.....................................................................................................................................................................

32 3.2. Evidence Assessment and Evaluation ..................................................................................................................

33 3.3. Safety...................................................................................................................................................................................

34 3.4. Quality Control................................................................................................................................................................

35 3.5. Documentation ...............................................................................................................................................................

36 3.6. Matrices..............................................................................................................................................................................

37 3.7. Equipment........................................................................................................................................................................

38 3.8. Application Methods ....................................................................................................................................................

39 Annexes (Labeled Alphabetically in order)..................................................................................................................XX

40 Annex A (Formulations) ......................................................................................................................................................XX

41 Annex B (Bibliographies)
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42 1 Scope

43 This document is a best practice recommendation for forensic professionals who are responsible 

44 for the collection and examination of footwear and/or tire impression evidence encountered at 

45 crime scenes or in the forensic laboratory. Transfer impressions are commonly made on a two 

46 dimensional surface by a footwear or tire as a result of coming in contact with and acquiring dust, 

47 residue, blood, mud, or other materials that the footwear or tire subsequently deposits or transfers 

48 to a substrate in the form of an impression. Following the recommendations in this document can 

49 result in developing additional detail and/or contrast in footwear and tire impression evidence. 

50 Chemical processing procedures that are commonly used in the forensic community are included.

51 This document does not purport to cover all chemical processing techniques or formulations that 

52 are available. Deviations from this document may preclude enhancement of impressions. This 

53 document is not intended as a substitute for training in chemical processing procedures for 

54 footwear and tire impression evidence. Completion of a training program and experience is 

55 essential to understanding and applying the principles outlined in this document. 

56

57 2 Terms and Definitions

58 Alginate: A natural polysaccharide commonly used for lifting impressions.

59

60 Amino acid: An organic compound containing amine (-NH2) and carboxyl (-COOH) functional 

61 groups, along with a side chain (R group)

62

63 Chemical Processing: A method or means of chemically changing one or more chemical compounds 

64 or substances typically via a color reaction.

65

66 Chemiluminescence: The low-temperature emission of light during a chemical reaction.

67

68 Control: A known standard or preparation for checking or verifying a test reagent.

69

70 Dental stone: A generic gypsum product generally having a rating of 8,000 psi or higher, commonly 

71 used to cast footwear and tire impressions.

72

73 Electrostatic lifter: An instrument which uses an electrostatic charge to transfer dry origin 

74 impressions from a substrate to a film.

75

76 Enhancement: Improving the visibility of an impression through physical, photographic, digital, 

77 optical, or chemical means.

78

79 False Negative: A test result which incorrectly indicates that a particular condition or attribute is 

80 absent.

81

82 False Positive: An unintended reaction which incorrectly indicates that a particular condition or 

83 attribute is present.

84

85 Fluorescence: Luminescence caused by the absorption of radiation at one wavelength followed by 

86 nearly immediate re-radiation usually at a different wavelength and that ceases almost at once 

87 when the incident radiation stops.

88
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89 Forensic Light Source: A filtered light source that may be fixed or tunable to a variety of spectral 

90 ranges.

91

92 Gelatin lifter: A commercial product with gelatin applied to a pliable backing used to lift 

93 impressions.

94

95 Hemoglobin: A protein of red blood cells that contains iron and carries oxygen from the lungs to the 

96 tissues and carbon dioxide from the tissues to the lungs.

97

98 Latent impression: An impression not readily visible to the naked eye.

99

100 Matrix/matrices: Substance(s) that are deposited or removed due to the result of coming in contact 

101 with a shoe or tire.

102

103 Oxidize: To combine or become combined chemically with oxygen.

104

105 Peroxidase reagent: An enzyme that catalyzes the oxidation of a particular substrate by hydrogen 

106 peroxide.

107

108 Phenolphthalein: A colorless crystalline solid used as a chemical indicator to detect for the possible 

109 presence of hemoglobin.

110

111 Physical techniques: Processes used to enhance or collect impressions such as lifting and casting 

112 methods (e.g. gelatin lifts, dental stone casts, alginate molds).

113

114 Reagent: Substance (usually a mixture or combination of chemicals) used in a chemical reaction to 

115 detect, examine, or produce other substances.

116

117 Safety Data Sheet (SDS): A document that contains information on the potential health effects of 

118 exposure to chemicals, or other potentially dangerous substances, and on safe working procedures 

119 when handling chemical products.

120

121 Sebaceous: Relating to the oil or waxy matter originating from the sebaceous glands.

122

123 Substrate: The surface upon which an impression is deposited.

124

125 Transfer impression: An impression made on a two dimensional surface by a footwear or tire as a 

126 result of coming in contact with and acquiring dust, residue, blood, mud, or other materials that the 

127 footwear or tire subsequently deposits or transfers to a substrate in the form of an impression.
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128 3 Recommendations

129 3.1 Introduction

130 3.1.1 Chemical processing can be used to develop additional details in impressions that are

131 faint or latent (non-visible). Chemical processing can also provide additional contrast

132 between the impression and the underlying substrate.

133 3.1.2 Optical, photographic, physical and digital techniques may be used in conjunction with 

134 chemical processing to further enhance impressions. 

135 3.1.2.1 An appropriate sequence of applications should be evaluated prior to processing.

136 3.1.2.2 Optical, photographic, and digital techniques for visualization/enhancement should 

137 be attempted prior to the chemical processing and physical techniques. 

138 3.1.2.3 Physical techniques can be used prior to, and after, chemical processing and may 

139 maximize the recovery of evidence. 

140 3.1.3 Chemical processing methods may be used individually or in sequence in order to 

141 maximize the recovery of evidence. 

142 3.1.4 Chemical processing may be used in a crime scene environment when an item of 

143 evidence cannot be removed from the scene. 

144 3.1.5 Consideration should be given to the removal of the impression evidence from the 

145 crime scene to be chemically processed in a controlled laboratory environment. 

146 Examples could include cutting out sections of flooring or drywall. Processing in a 

147 laboratory setting may allow for better control of the process and for the use of a

148 greater variety of techniques.

149 3.2 Evidence Assessment and Evaluation

150 3.2.1 No single methodology exists for the chemical processing of impression evidence on 

151 all surfaces under all conditions. The training and experience of the practitioner is 

152 crucial to ensure that the variables associated with the evidence are considered and 

153 evaluated prior to chemical processing.

154 3.2.2 Variables to be evaluated and considered prior to attempting chemical processing

155 may include:

156 3.2.2.1 Substrate composition (e.g. texture, porosity)

157 3.2.2.2 Substrate color

158 3.2.2.3 Substrate orientation (e.g. horizontal or vertical surfaces)

159 3.2.2.4 Stain/deposit matrices of the impression

160 3.2.2.5 Environmental conditions and/or limitations
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161 3.2.2.6 Subsequent testing requirements (e.g. deoxyribonucleic acid (DNA) analysis)

162 3.2.3 Chemical processing reagents are specific to the stain/deposit matrices that are to be 

163 enhanced. Impressions should be assessed prior to selecting the chemical processing 

164 reagents to determine the possible matrix. General categories of common matrices 

165 are:

166 3.2.3.1 Blood

167 3.2.3.2 Environmental/Particulate deposits (elements or ions within dirt, dust, water)

168 3.2.3.3 Organic contaminants (skin, sebaceous, amino acids)

169 3.2.4 Impressions that may require subsequent DNA testing (e.g. blood, skin, etc.) should be 

170 sampled prior to enhancement provided that this will not destroy any detail that may 

171 be needed for comparison. Chemical processing techniques should be reviewed prior 

172 to use to ensure they are compatible with subsequent DNA analysis but DNA analysis 

173 on samples collected after chemical processing may be possible. Depending upon the 

174 situation additional sterile techniques may be necessary to prevent DNA 

175 contamination.

176 3.2.5 Avoid techniques and chemical processing which may compromise other forensic 

177 analyses that may be required.

178 3.3 Safety 

179 3.3.1 Personal protective equipment such as lab coats, disposable sleeves, coveralls, shoe 

180 covers, eye protection, face masks, and gloves should be appropriately worn when 

181 preparing and using reagents. 

182 3.3.2 Mix, and if possible, use chemicals in well ventilated areas or a chemical fume hood. 

183 3.3.3 It is recommended that only water-based reagents be used in the field due to safety 

184 issues (e.g. flammability) with solvent-based reagents. 

185 3.3.4 Face masks, respirators with appropriate filters, and fume hoods are recommended 

186 when applying reagents (spraying, toweling, pooling) in the field or lab.

187 3.3.5 Refer to relevant chemical Safety Data Sheets (SDS) for further information and 

188 precautions.

189 3.4 Quality Control

190 3.4.1 Reagents should be prepared using clean glassware, equipment and containers. The 

191 preparation area should be clean and free of contaminants.
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192 3.4.2 At a minimum, containers should be labeled with the reagent name, date of 

193 preparation, initials of preparer and expiration date (if applicable) and other 

194 information as required. 

195 3.4.3 A reagent preparation log may be maintained with the formulation used for each 

196 reagent, the lot numbers of the chemicals used, the date created, and initials of who 

197 prepared the reagent. SDS documents may also be contained within this log.

198 3.4.4 Prior to application on evidence, reagents shall be tested on known control samples to 

199 demonstrate that they react as expected. Information of what control was used and 

200 the results observed should be recorded. In some cases the reagent may also need to 

201 be tested against a small portion of impression, or sample of the stain/deposit, so as to 

202 make sure that the expected reaction takes place. Caution should be used when 

203 working with previously prepared reagents as they may have a limited shelf life.

204 3.4.5 It is recommended that a non-evidential area of the substrate be tested with each 

205 reagent to evaluate potential processing limitations such as poor de-staining, 

206 degradation of the substrate, or if the particular substrate also reacts with the reagent. 

207 This is particularly important if a sequence of more than one processing technique 

208 will be applied.

209 3.4.6 Commercially prepared reagents are available and may be used. Follow the 

210 manufacturer’s instructions for these products. It is recommended that all quality 

211 control measures mentioned above be followed.

212 3.5 Documentation

213 3.5.1 Footwear and tire impressions should be documented prior to, during, and after 

214 processing. At a minimum, documentation should include photography but can also 

215 include diagrams, sketches, video, and notes.

216 3.5.2 Any impressions that have the potential to be used for comparison purposes shall be 

217 photographed using proper techniques prior to enhancement, and after enhancement, 

218 to capture examination quality photographs. 

219 3.6 Matrices

220 3.6.1 Blood: Blood is commonly encountered at crime scenes and enhancement reagents for 

221 blood typically cause a color reaction with the protein components, or the heme group 

222 in hemoglobin, which are found in blood. Considerations for impressions in blood

223 include the following:

224 3.6.1.1 Presumptive testing using a blood reagent such as phenolphthalein can be done in 

225 order to determine whether or not an impression could be blood. Precautions 

226 should be made to ensure that there is no loss in detail for comparison and the 

227 stain/deposit is not consumed in sampling. 
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228 3.6.1.2 It is recommended that impressions in blood that may require subsequent DNA 

229 testing should be sampled prior to enhancement, provided that this will not 

230 destroy any detail that may be needed for comparison. 

231 3.6.1.3 Physical techniques can also be used prior to and after chemical processing of the 

232 impressions in blood.

233 3.6.1.4 Blood should be completely dry prior to chemical enhancement.

234 3.6.1.5 Fainter impressions may offer more opportunity for clarity/improved contrast 

235 with chemical processing than impressions with heavy deposits. 

236 3.6.1.6 In general, older stains may be more receptive to chemical processing than fresh 

237 stains. Stains which exhibit suspected clean-up with bleach may also yield 

238 improved results with chemical processing after a period of time so that the 

239 bleach has degraded to form salt and oxygen which does not interact with the 

240 reagent.

241 3.6.1.7 With the exception of luminol, impressions in blood must be dry or fixed to the 

242 substrate prior to or during any chemical enhancement. For impressions 

243 containing a lot of blood, it may be desirable to pre-fix the impressions before 

244 chemical enhancement even if the fixative is included in a particular solution. A 

245 wipe of blood on a piece of clear acetate as a control allows for both the fixing and 

246 enhancement properties of the reagent to be tested. 

247 3.6.1.8 Sequencing of chemicals can be done in the following order; peroxidase reagent 

248 (e.g. luminol, leucocrystal violet (LCV)) followed by protein stain (e.g. amido 

249 black). Generally, the peroxidase reagents are more sensitive for blood than the 

250 protein stains.

251 3.6.1.9 Impressions in blood can be lifted (gelatin, dental stone, alginate) post252 enhancement from a surface in order to provide better contrast.

253 3.6.1.10 Luminol and LCV are particularly useful for spray applications over large areas. 

254 Amido black and Acid Yellow 7 are generally limited to the localized development 

255 of impressions.

256 3.6.1.11 Prior to application on evidence, reagents shall be tested on known control 

257 samples to demonstrate that they react as expected. Information of what control 

258 was used and the results observed (color change) should be recorded. In some 

259 cases the reagent may also need to be tested against a small portion of impression, 

260 or sample of the stain/deposit, so as to make sure that the expected reaction takes 

261 place. 

262 3.6.1.12 It is recommended that a non-evidential area of the substrate be tested with each 

263 reagent to evaluate potential processing limitations such as poor de-staining, 

264 degradation of the substrate, or if the particular substrate also reacts with the 

265 reagent. This is particularly important if a sequence of more than one processing 

266 technique will be applied.
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267 3.6.1.13 Even though unintended reactions can occur they can be useful in enhancing 

268 questioned impressions. For example, proteinaceous materials such as egg 

269 albumin will be enhanced with amido black. 

270 3.6.1.14 None of the enhancement reagents are specific to human blood and will react with 

271 animal blood as well.

272 3.6.2 Environmental/Particulate deposits: Dust, dirt, or particulate impressions are 

273 commonly encountered at a scene of a crime. Sometimes the material which has been 

274 deposited may react with enhancement reagents based upon the reaction with the 

275 elements such as iron or calcium and ions such as carbonate. Considerations for 

276 impressions made in these deposits include the following:

277 3.6.2.1 Physical techniques can be used prior to, and after, chemical processing and may 

278 maximize the recovery of evidence. For example, an electrostatic lifter can be used 

279 first to lift dry residue impressions. 

280 3.6.2.2 Faint impressions offer more opportunity for clarity/improved contrast with 

281 chemical processing than impressions with heavy deposits. 

282 3.6.2.3 Enhanced impressions can be lifted (gelatin, dental stone, alginate) post283 enhancement from a surface in order to provide better contrast.

284 3.6.2.4 Prior to application on evidence, reagents shall be tested on known control 

285 samples to demonstrate that they react as expected. Information of what control 

286 was used and the results observed (color change) should be recorded. In some 

287 cases the reagent may also need to be tested against a small portion of impression, 

288 or sample of the stain/deposit, so as to make sure that the expected reaction takes 

289 place. 

290 3.6.2.5 It is recommended that a non-evidential area of the substrate be tested with each 

291 reagent to evaluate potential processing limitations such as poor de-staining, 

292 degradation of the substrate, or if the particular substrate also reacts with the 

293 reagent. This is particularly important if a sequence of more than one processing 

294 technique will be applied.

295 3.6.2.6 False positive reactions may occur with all of the enhancement reagents.

296 3.6.3 Organic components: There may be instances in which skin secretions are the matrix 

297 which gets deposited as an impression. This may have more use in enhancing 

298 impressions on clothing which may also involve blood but where other blood 

299 enhancements are inadequate, or are not successful, for the matrix. Considerations 

300 for impressions made in these deposits include the following:

301 3.6.3.1 One must consider if the deposit may require subsequent DNA testing. If so, a 

302 portion of the deposit should be sampled prior to enhancement provided that this 

303 will not destroy any detail that may be needed for comparison. 
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304 3.6.3.2 Prior to application on evidence, reagents shall be tested on known control 

305 samples to demonstrate that they react as expected. Information of what control 

306 was used and the results observed (color change) should be recorded. In some 

307 cases the reagent may also need to be tested against a small portion of impression, 

308 or sample of the stain/deposit, so as to make sure that the expected reaction takes 

309 place. 

310 3.6.3.3 It is recommended that a non-evidential area of the substrate be tested with each 

311 reagent to evaluate potential processing limitations such as poor de-staining, 

312 degradation of the substrate, or if the particular substrate also reacts with the 

313 reagent. This is particularly important if a sequence of more than one processing 

314 technique will be applied.

315 3.6.3.4 False positive reactions may occur with all of the enhancement reagents.

316 3.7 Equipment

317 3.7.1 Spatula

318 3.7.2 Scale (“L” scales and straight scales)

319 3.7.3 Spray bottles (fine mist) 

320 3.7.4 Stirring device

321 3.7.5 Graduated cylinders 

322 3.7.6 Erlenmeyer flasks 

323 3.7.7 Clear and/or dark storage bottles

324 3.7.8 Paper towel

325 3.7.9 Tongs

326 3.7.10 Glass trays

327 3.7.11 Disposable pipettes

328 3.7.12 Rinse bottle

329 3.7.13 Chalk

330 3.7.14 Forensic light source and appropriate goggles/glasses

331 3.7.15 Camera and accessories (refer to the document entitled “Best Practice 

332 Recommendation for Photographic Documentation of Footwear and Tire Impression

333 Evidence” for further guidance)

334 3.7.16 Camera filters
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335 3.7.17 Personal protective equipment

336 3.8 Application Methods

337 Chemical processing reagents may be applied through different methods. The general application 

338 methods are described below. Refer to the individual chemical processing formulations in Annex A

339 of this document for specific application guidance.
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340 3.8.1 Spraying

341 3.8.1.1 Use a fine mist sprayer to spray the chemical processing reagents onto the area to 

342 be developed or fixed.

343 3.8.1.2 Pump or garden sprayers that dispense a larger volume of liquid or large droplets 

344 are not recommended.

345 3.8.1.3 The use of sprayers can leave artifacts on the impression so the process should be 

346 monitored closely during application.

347 3.8.2 Toweling

348 3.8.2.1 Place a piece of paper towel over the area to be developed or fixed and apply the 

349 chemical processing reagents with a spray bottle or mist sprayer. 

350 3.8.2.2 Do not use paper towels containing additives such as lotions or perfumes. Paper 

351 towels with textured patterns should also be avoided as they may interfere with 

352 the development process. Paper towels must also be sturdy enough not to 

353 degrade during processing.

354 3.8.2.3 Air pockets may be removed using a roller to assure that all areas of the 

355 impression are treated.

356 3.8.2.4 Leave the wet towel in place until development or fixation is complete. Remove 

357 the towel and rinse the impression with distilled water or suitable rinse solution 

358 as described for each chemical processing formulation.

359 3.8.3 Immersion

360 3.8.3.1 This application method may be used for items containing impressions that are 

361 relatively small and mobile.

362 3.8.3.2 Place the item containing the impression into a tray of the chemical processing 

363 reagent and leave it in place until development or fixation is complete.

364 3.8.3.3 Remove the item and rinse with distilled water or suitable rinse solution as 

365 described for each chemical processing formulation.

366 3.8.4 Pooling

367 3.8.4.1 This application method may be used for items that are too large to move or are 

368 otherwise immobile such as flooring, walls, or cabinets. 

369 3.8.4.2 Apply the chemical processing reagents to the item containing the impression 

370 using a disposable pipette, squeeze bottle, or other container. 

371 3.8.4.3 Leave the reagents in place until development or fixation is complete.

372 3.8.4.4 Gently remove the excess reagent using a paper towel.

373
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374 Annex A

375 (Formulations)

376

377 2% Sulfosalicylic Acid (2 % SSA) Fixative

378 A.1 Background

379 Blood is water soluble. A 2% solution of SSA is used to fix an impression in blood through the 

380 denaturing of proteins to the underlying substrate, prior to the application of aqueous-based 

381 reagents. This ensures that the impression is not dissolved or washed away during processing.

382 Do not use the fixative prior to the application of luminol as it will inhibit the chemiluminescence. 

383 Some reagent formulations may contain SSA (e.g. leucocrystal violet (LCV)). SSA should be used prior 

384 to enhancement with amido black and Acid Yellow 7.

385 A.2 Formulation

386 Combine 20 grams of 5-sulfosalicylic acid and 1 liter of distilled water to make a 2% solution.

387 Store in a dark bottle at room temperature.

388 Indefinite shelf life.

389 A.3 Quality Control

390 A wipe of blood on an acetate sheet can be used as a control to test the fixative properties. Leave 

391 fixative on the surface for 3-5 minutes and then rinse with water. Observe that no loss of detail is 

392 present. 

393 A.4 Procedure

394 Apply using fine mist sprayer or through the immersion, pooling or toweling techniques. Leave on 

395 the impression for 3-5 minutes and carefully remove any excess solution using a clean paper towel.

396 A.5 References 

397 Hussain, J. I.; Pounds, C. A., “The Enhancement of Marks in Blood, Part I, 5-Sulphosalicyclic acid: A 

398 Convenient and Effective Fixative for Marks Made in Blood”, CRE Report No. 649, Feb 1988.

399
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400 Acid Yellow 7

401 A.1 Background

402 Acid Yellow 7 is a dye solution that is used for staining impressions made in blood. These 

403 impressions are stained yellow after treatment with Acid Yellow 7 and then fluoresce under 

404 blue/blue-green light. This technique is used to develop bloody latent impressions on dark, non405 porous surfaces.

406

407 A.2 Formulation

408 Staining Solution: 

409 1 g Acid Yellow 7

410 40 mL glacial acetic acid

411 250 mL ethanol

412 700 mL distilled water

413 Fixative Solution: 

414 As the above reagent does not have a fixative one must use a fixative reagent such as 2% SSA.

415 Rinsing Solution: 

416 40 mL glacial acetic acid

417 250 mL ethanol

418 700 mL distilled water

419 A.3 Quality Control

420 Deposit known blood control onto white substrate or medium of choice and spray with Acid Yellow. 

421 A positive test will result in fluorescence when viewed with a forensic light source in the 400nm422 495nm range using a yellow or orange filter.

423 A.4 Procedure

424

425 Fix the impression with the Fixative Solution (2% sulfosalicylic acid (2% SSA)) and rinse with 

426 distilled water. Stain a small area of the evidence (separate from the impression) to check for 

427 background staining. If background staining occurs and will not rinse away with water, use a 

428 different enhancement method. 

429 Spray the area with the staining solution and leave the stain to be in contact with the impression 

430 area for approximately 5 minutes. 

431

432 Rinse thoroughly with rinse solution and allow to dry. 

433
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434 Observe the impression area using a forensic light source in the 400nm-495nm range using a 

435 yellow or orange filter. 

436

437 The remaining blood may be further collected using a gelatin lifter.

438

439 A.5 References 

440 Sears, V.G., Butcher, C.P.G., Fitzgerald, L.A., Enhancement of Fingerprints in Blood, Part 3: Reactive 

441 Techniques, Acid Yellow 7 and Process Sequences, Journal of Forensic Identification, 55(6): 741-763, 

442 2005.
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443 Amido Black – One Step (Water-Based) 

444 A.1 Background

445 This enhancement procedure uses a water soluble dye that reacts with the protein in blood that 

446 produces a dark blue-black color in areas where blood is present. This amido black water-based 

447 formula is a one-step process which eliminates the need for a separate fix solution as it is 

448 incorporated into this formula. The amido black method can be used after treatment with 

449 leucocrystal violet (LCV) enhancement to further increase contrast. 

450 A.2 Formulation

451 Using a stirring device, combine the following ingredients in the order that they are listed. 

452 500 mL Distilled water 

453 20 g 5-Sulfosalicylic acid 

454 3 g Amido black (also known as amido 10B or naphthalene black) 

455 3 g Sodium carbonate 

456 50 mL Formic acid 

457 50 mL Acetic acid 

458 12.5 mL Kodak Photo-Flo 600 solution 

459 Dilute this mixture to one liter using distilled water. For best results allow the mixture to stand (if 

460 possible) for several days prior to use. 

461 A.3 Quality Control

462 Test the reagent with a known blood control. A positive reaction is a dark blue-black color. 

463 A.4 Procedure

464 Using the amido black reagent, stain a small area of the evidence that is separate from the 

465 impression to check for background staining. If background staining occurs and will not rinse away 

466 with water, use a different enhancement method. 

467 Apply the reagent to the area by either dipping, using a rinse bottle or apply using a fine mist. 

468 Completely cover the area in question and allow the area to develop for approximately 2 – 5 

469 minutes. Once developed, rinse the area with distilled water. 

470 A.5 References 

471 Bodziak, W.J., Forensic Footwear Evidence. CRC Press: Boca Raton, FL: CRC Press; 2017.

472
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473 Amido Black (Methanol-Based)

474 A.1 Background

475 This enhancement procedure uses a water soluble dye that reacts with the protein in blood that 

476 produces a dark blue-black color in areas where blood is present. This amido black methanol-based 

477 formula is a three-step process which requires the need for a separate fixative solution. The amido 

478 black method can be used after treatment with leucocrystal violet (LCV) enhancement to further 

479 increase contrast. Amido black is best used on nonporous substrates and whose background does 

480 not absorb the stain.

481 A.2 Formulation

482 Fixative Solution: 

483 20 g 5-Sulfosalicylic acid 

484 1000 mL Distilled water 

485 Thoroughly dissolve the 5-sulfosalicylic acid in water. 

486 Staining Solution: 

487 900 mL Methanol 

488 100 mL Glacial acetic acid 

489 2 g Amido black (also known as amido 10B or naphthalene black) 

490 Thoroughly dissolve the amido black in the acid/methanol solution. 

491 Rinsing Solution: 

492 900 mL Methanol 

493 100 mL Glacial acetic acid 

494 A.3 Quality Control

495 Test the reagent solutions with a known blood control. A positive reaction is a dark blue-black 

496 color. 

497 A.4 Procedure

498 Fix the impression with the Fixative Solution and rinse with distilled water. Stain a small area of the 

499 evidence (separate from the impression) to check for background staining. If background staining 

500 occurs and will not rinse away with prepared rinsing solution, use a different enhancement method. 

501 Apply the staining reagent to the area by either dipping, using a rinse bottle or apply using a fine 

502 mist. Completely cover the area in question and allow the area to develop for approximately 2 – 5 
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503 minutes. Once developed, use the rinsing solution and allow the area to dry. This step should not be 

504 eliminated as it helps to remove the stain from the background. 

505 A.5 References 

506 Bodziak, W.J., Forensic Footwear Evidence. CRC Press: Boca Raton, FL: CRC Press; 2017.

507 Barnett, K. G., Bone, R. G., Hall, P. W. and Ide, R. H. (1988) The Use of Water Soluble Protein Dye for 

508 the Enhancement of Footwear Impressions in Blood on Non-Porous surfaces Part 1, Forensic Science 

509 Service UK, Technical Note No. 629, July. London: Home Office.

510

511 Sears, V. G. and Prizeman, T. M. (2000) ‘The Enhancement of Fingerprints in Blood – Part 1: The 

512 Optimization of Amido Black’, Journal of Forensic Identification, vol. 50 (5), p 470.

513
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514 Ammonium and Potassium Thiocyanate 

515 A.1 Background

516 The thiocyanate ion, in an acid environment, will react with iron ions. Since iron is frequently found 

517 in soil and fertilizers, this method is a good choice for dirt or dust impressions. 

518 A.2 Formulation

519 Potassium Thiocyanate:

520 Mix 15 ml of water with 120 ml of acetone. 

521 Add 15 g of potassium thiocyanate. 

522 Slowly add 10 ml of dilute sulfuric acid (1 ml of concentrated sulfuric acid to 9 ml of water) to the 

523 above mixture.

524 Always add the sulfuric acid to the acetone/water mixture. Do not add the acetone/water mixture 

525 to the acid or it may explode. 

526 A milky mixture will result which will separate on standing. When the layers have separated, the top 

527 (clear) layer is removed and transferred to a glass bottle or spray unit. This is the working solution 

528 and is best if used immediately. 

529 Ammonium Thiocyanate:

530 Mix 2g of ammonium thiocyanate in 90 mL of acetone. 

531

532 Add 10ml of dilute nitric acid to the ammonium thiocyanate/acetone mixture.

533 Always add the nitric acid to the ammonium thiocyanate/acetone mixture. Do not add the 

534 ammonium thiocyanate/acetone mixture to the acid or it may explode. 

535 No precipitation will result; no separation is required as with potassium thiocyanate.

536 A.3 Quality Control

537 The reagent is checked by using ferric chloride (or a comparable iron standard). A positive reaction 

538 will result in a red/brown color. 

539 A.4 Procedure

540 It is best to check the thiocyanate solutions with the material which makes up the impression. A 

541 portion of this material is removed (if possible) and sprayed. If there is only a small amount of 

542 material which makes up the impression (and removal could disturb the impression) then a portion 

543 of the impression is isolated by a physical barrier and sprayed. A positive reaction will result in a 

544 red/brown color. 

545 If no positive reaction occurs, the thiocyanate enhancement should not be done. 
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546 The solution is lightly sprayed (fine mist) and the amount of spraying should be controlled to get 

547 the maximum reaction without causing the impression to run or bleed. 

548 If the reagent is not used immediately, it is best to be stored in a dark glass bottle. 

549 A.5 References 

550 Bodziak, W.J., Forensic Footwear Evidence. CRC Press: Boca Raton, FL: CRC Press; 2017.

551 Bodziak, W.J. Footwear Impression Evidence: Detection, Recovery, and Examination. 2nd Ed. Boca 

552 Raton, FL: CRC Press; 2000.

553 Froude, J.H. Using Ammonium Thiocyanate and Potassium Thiocyanate, Journal of Forensic 

554 Identification, 48:718 -724, 1998.
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555 Bromophenol Blue

556

557 A.1 Background

558 Bromophenol, a pH indicator, can be used to enhance impressions in dust by reacting with calcium 

559 carbonate. 

560 A.2 Formulation

561 Combine 20 grams of bromophenol blue and 1 liter of distilled water to make a 2% solution.

562 A.3 Quality Control

563 The reagent is checked by using calcium carbonate. A positive reaction will be a color change to 

564 blue.

565 A.4 Procedure

566 It is best to check the bromophenol blue solution with the material which makes up the impression. 

567 A portion of this material is removed (if possible) and sprayed. If there is only a small amount of 

568 material which makes up the impression (and removal could disturb the impression) then a portion 

569 of the impression is isolated by a physical barrier and sprayed. A positive reaction will result in a 

570 blue color. 

571 If no positive reaction occurs, the enhancement should not be done. 

572 The solution is lightly sprayed (fine mist) and the amount of spraying should be controlled to get 

573 the maximum reaction without causing the impression to run or bleed. If a reaction occurs but the 

574 color is yellow rather than blue, lightly spray water on the impression which should cause the 

575 impression to turn blue.

576 A.5 References 

577 Glattstein, B., Shor, Y., Levin, N., Zeichner, A., pH Indicators as Chemical Reagents for the 

578 Enhancement of Footwear Marks, Journal of Forensic Sciences, 41 (1) (1996) 23-26.

579

580 McNeil, K., Knaap, W. Bromophenol Blue as a Chemical Enhancement Technique for Shoeprints. 

581 Journal of Forensic Identification, vol. 62(2), p. 143-153, 2012.
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582 1,8-Diazafluoren-9-one (DFO)

583

584 A.1 Background

585 DFO is an amino acid reagent with fluorescent properties and can be used on porous surfaces which 

586 includes gel lifts.

587 A.2 Formulation

588 DFO stock solution:

589 1 g DFO crystals

590 200 mL Methanol

591 200 mL Ethyl Acetate

592 40 mL Glacial Acetic acid

593 Combine and stir with a magnetic stirrer until all ingredients are dissolved.

594 DFO working solution:

595 Add Petroleum ether to the stock solution until the total volume is 2 liters.

596 A.3 Quality Control

597 Place an amino acid rich deposit onto a porous surface and process with DFO. A positive test will 

598 fluoresce with the use of a laser or forensic light source. 

599

600 A.4 Procedure

601 Submerge or spray the item for 5 seconds.

602

603 Air-dry the item in a fume hood.

604

605 Process the item a second time and air-dry the item in a fume hood.

606

607 Oven bake at 50 to 100 degrees C for 10 to 20 minutes.

608

609 View under a forensic light source at 495 nm to 550 nm. (Absorption Max is 514 nm. 

610 View under orange or red barrier filters.)

611

612 Image results using an orange colored or 550 (BP 35) bandpass filter.

613

614 A.5 References 

615 Masters, Nietial, “DFO, Its Usage and Results”, Journal of Forensic Identification, vol. 41 (1), p 3, 

616 1991.

617
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618 Champod, C.; Lennard, C.; Margot, P.; Stoilovic, M., Fingerprints and Other Ridge Skin Impressions,

619 CRC Press: Boca Raton, FL, 2004, pp. 128-131.

620

621 Didierjean, C., Debart, M-H, Crispino, F., New Formulation of DFO in HFE-7100, Fingerprint Whorld, 

622 Vol. 24, No. 94, October 1998, pp.163-167.

623

624 Conn, C, Ramsay, G., Roux, C., Lennard, C., The Effect of Metal Salt Treatment on the 

625 Photoluminescence of DFO-Treated Fingerprints, Forensic Science International, vol. 116, no. 2, 

626 2001, pp. 117-123.

627

628 Merrick, S., Gardner, S.J., Sears, V. and Hewlett, D.F., An Operational Trail of Ozone-Friendly DFO and 

629 1,2-Indanedione Formulations for Latent Fingerprint Detection, Journal of Forensic Identification, 

630 vol. 52, no. 5, Sept./Oct. 2002, pp. 595-605.

631

632 Pounds, C.A., Grigg, R., Mongkolaussavaratana, T., The Use of 1,8-Diazafluoren-9-one (DFO) for the 

633 Fluorescent Detection of Latent Fingerprints on Paper: A Preliminary Evaluation, Journal of Forensic 

634 Sciences, vol. 35, no. 1, 1990, pp. 169-175.

635

636 Wilkinson, D., Study of the Reaction Mechanism of 1,8-Diazafluoren-9-one with the Amino Acid, L637 Alanine, Forensic Science International, vol. 109, no. 2, 2000a, pp. 87-103. 

638

639 Chemical Formulas and Processing Guide for Developing Latent Prints, U.S. Dept. of Justice, pg. 47-

640 48, 1994.

641

642 Manual of Fingerprint Development Techniques 2nd. Ed., Home Office - Police Scientific 

643 Development Branch, White Crescent Press, Ltd., Luton, England, 2001.

644

645 Bodziak, W.J., Forensic Footwear Evidence. CRC Press: Boca Raton, FL: CRC Press; 2017.

646 Bodziak, W.J. Footwear Impression Evidence: Detection, Recovery, and Examination. 2nd Ed. Boca 

647 Raton, FL: CRC Press; 2000.

648 Hamer, P., Price, C., Case Report: a Transfer from Skin to Clothing by Kicking – The Detection and 

649 Enhancement of Shoeprints”, Journal of the Forensic Science Society, 33(3), 169-172, 1993.

650
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651 Hungarian Red

652 A.1 Background

653 Hungarian Red is a dye (Acid Fuchsin) solution in water/acetic acid mixture used for staining 

654 footwear impressions made in blood on non-porous surfaces.

655 A.2 Formulation

656 Fixative Solution:

657 2% Sulfosalicylic Acid Solution

658 5% Acetic Acid Washing Solution:

659 Add 10 mL of glacial acetic acid to 190 mL of distilled water in a large beaker.

660 Using a magnetic stir bar, stir the solution for 5 minutes.

661 Place the solution in a rinse bottle until needed.

662 Distilled water may be used in place of acetic acid solution. 

663 Hungarian Red Working Solution:

664 Hungarian Red is available in a premixed solution and does not require prior mixing of this 

665 solution.

666 The solution should be placed in a rinse bottle to apply to an item of evidence.

667 A.3 Quality Control

668 Test the reagent with a known blood control. A positive reaction is a red color. 

669 A.4 Procedure

670 Prior to spraying the item of evidence with any of the solutions, the bloody impression should be 

671 dried or cured to prevent the impression from dissolving when the solution is applied.

672

673 Cover the bloody impression with filter or tissue paper.

674

675 Spray the sulfosalicylic acid solution onto the tissue paper. Allow the tissue paper to remain on the 

676 item of evidence for two (2) minutes. For larger thick stains, the tissue should remain for a longer 

677 period of time.

678

679 Rinse the area of interest with distilled water.

680
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681 Apply the Hungarian Red solution with a rinse bottle to the item of evidence ensuring the entire area 

682 is covered.

683

684 Wash the excess solution with the acetic acid solution (distilled water may be substituted in the step). 

685 Immediately blot any excess solution with the tissue paper.

686

687 Allow the item to dry (a hair dryer may be used to expedite the process).

688

689 When completely dry, place a white gelatin lifter over the impression. Leave the gelatin lifter on the 

690 impression for fifteen (15) to thirty (30) minutes.

691

692 Remove the gelatin lifter and view the lift with the laser or alternate light source. The most 

693 appropriate wavelengths are within the 515 to 560 nm range with a green filter and 600 nm with a 

694 red filter.

695 A.5 References 

696 Kent, T., ed. Manual of Fingerprint Development Techniques: A Guide to the Selection and Use of 

697 Processing for the Development of Latent Fingerprints. Police Scientific Development Branch, 

698 London (July 1992). 

699 Lee, H.C. Methods of Latent Print Development. Proceedings of the International Forensic 

700 Symposium on Latent Prints. (July 1987): 15 – 24. 

701 Lennard, C.J. and P.A. Margot. Sequencing of Reagents for the Improved Visualization of Latent 

702 Fingerprints. Proceedings of the International Forensic Symposium on Latent Prints. (July 1987): 

703 141-142. 

704 Manual of Fingerprint Development Techniques. (January 1986): 2-8. 

705 Manual of Fingerprint Development Techniques: A Guide to the Selection and Use of Processes for 

706 the Development of Latent Fingerprints. Scientific Research and Development Branch, London 

707 (1986). 

708 Trozzi, T.A., R.L. Schwartz and M.L. Hollars. Processing Guide for Developing Latent Prints. (2000): 

709 1-64. US Department of Justice. 

710 Chemical Formulas and Processing Guide for Developing Latent Prints. FBI Laboratory Division, 

711 Latent Fingerprint Section (1994). 

712 Bodziak, W.J., Forensic Footwear Evidence. CRC Press: Boca Raton, FL: CRC Press; 2017.

713 http://bvda.com/en/hungarian-red
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714 Leucocrystal Violet (LCV)

715 A.1 Background

716 Leucocrystal violet is the reduced or colorless form of crystal violet. When LCV and hydrogen 

717 peroxide come into contact with hemoglobin or its derivatives, a violet colored dye (crystal violet) 

718 is formed through the catalyzed oxidation from peroxide. This formulation includes a blood fixative, 

719 5-sulfosalicylic acid. LCV is commonly used for application in large areas.

720 A.2 Formulation

721 Dissolve 10 grams of 5-sulfosalicylic acid in 500 mL of 3% hydrogen peroxide using a 500 mL

722 bottle. (The 3% hydrogen peroxide sold in 473 mL bottles in stores also can be used.) 

723 Add 4.4 grams of sodium acetate. 

724 Add 1.1 grams of Leucocrystal violet. 

725 If the LCV crystals are yellow instead of white, do not use. This means that the crystals are old and 

726 the solution may not be effective. 

727 A.3 Quality Control

728 Test the reagent with a known blood control. A positive reaction is a dark violet color. 

729 A.4 Procedure

730 Using the LCV reagent, spray a small area of the evidence that is separate from the impression to 

731 check for background staining. If background staining occurs and will not rinse away with water, 

732 use a different enhancement method. 

733 Apply the reagent to the area by spraying a fine mist, soaking the area or by cascading the LCV over 

734 the area’s surface. 

735 On non-porous surfaces, such as tile, and on porous surfaces, when possible, the area should be 

736 rinsed with water approximately 2 to 3 minutes after the reagent has been applied. 

737 LCV fluoresces and can be viewed and/or photographed under various wavelengths of ultraviolet 

738 and infrared light.

739 This solution must be stored in an amber bottle as it is light sensitive. This solution may be 

740 refrigerated to extend its reactivity. The solution shelf life is 30 days. 

741 Amido black can be used after LCV treatment to further increase contrast. 

742 A.5 References 

743 Bodziak, W. J. (1996) Use of Leuco-Crystal Violet to Enhance Shoeprints in Blood, Forensic Science

744 International, vol. 82, p 45.

745
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746 Bodziak, W.J., Forensic Footwear Evidence. CRC Press: Boca Raton, FL: CRC Press; 2017.

747 Bevel, T., Gardner, R.M., Bloodstain Pattern Analysis, 2nd ed., CRC Press, Boca Raton, FL, 2002.

748
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749 Luminol

750

751 A.1 Background

752 Luminol is a chemical that reacts with the heme compounds found in blood to produce a blue753 colored chemiluminescence visible in a darkened area. Luminol is also known to react in a similar 

754 manner with other oxidizing agents (e.g. bleach). Luminol may assist in crime scenes where blood 

755 has been cleaned up from a surface and is no longer visible to the naked eye. Luminol can readily 

756 detect old bloodstains and minute amounts of blood that have been diluted or cleaned up. 

757

758 A.2 Formulation

759 Dissolve 0.1 gram of Luminol and 5 grams of sodium carbonate in 100 mL of water. 

760 Add 0.7 gram of sodium perborate and mix thoroughly. 

761 Use reagent immediately.

762 A.3 Quality Control

763 This reagent should be used in a dark environment. The reagent is checked by using a copper 

764 standard (a penny) or a known blood control. A positive reaction will result in chemiluminescence. 

765 A.4 Procedure

766 The area where the luminol reagent will be used should be as dark as possible. Extinguish all light 

767 sources and, if necessary, cover windows with some kind of material to darken the area. 

768 Spray a fine mist of the reagent solution in a sweeping motion over the area of interest. Avoid 

769 saturation of the area. 

770 If a positive reaction of an impression is observed, additional misting may be necessary for 

771 photography, with care taken not to dilute the stain. 

772

773 Consideration should be given to presumptive testing for the presence of blood (e.g. 

774 phenolphthalein) and preservation for further DNA testing.

775

776 The reagent is a one-time use reagent and should be mixed immediately prior to use.

777 A.5 References 

778 Weber, K. (1966) Die Anwendung der Chemiluminescenz des Luminols in der Gerichtlichen Medizin 

779 und Toxikologie, Deutsche Zeitschrift für Gerichtliche Medizin, vol. 57, p 10.

780

781 Lytle, L., Hedgecock, D., Chemiluminesence in the Visualization of Forensic Bloodstains, Journal of 

782 Forensic Sciences, 23(3): 550-562, 1978.

783

784 Cheeseman, R., Direct Sensitivity Comparison of the Fluorescein and Luminol Bloodstain 

785 Enhancement Technique, Journal of Forensic Identification, 49(3), 631-646, 1995.

786
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787 Ninhydrin

788

789 A.1 Background

790 Ninhydrin is an amino acid developing reagent applied by dipping, brushing, or spraying. 

791 Development is catalyzed by the addition of heat and humidity to obtain a Ruhemann’s Purple dye 

792 complex. Ninhydrin may also be used as a blood enhancement technique.

793

794 A.2 Formulation

795 5 g ninhydrin crystals

796 30 mL methanol

797 40 mL 2-propanol

798 930 mL petroleum ether

799 A.3 Quality Control

800 Place an amino acid rich deposit onto a porous surface, process with Ninhydrin, and transfer into a 

801 heat/humidity chamber. A positive test will result in a purple color. 

802

803 A.4 Procedure

804 Application of the Ninhydrin solution may be accomplished through spraying, brushing, or dipping. 

805 After treating the evidence with the Ninhydrin solution, allow it to dry at room temperature. A 24-

806 hour development period is recommended. Subjecting the item to a combination of heat and 

807 humidity can accelerate the reaction. 

808

809 A.5 References

810 Ruhemann, S., Journal of the Chemical Society, Transactions, 97 (1910):2014

811 Oden, S. and B. von Hofsten, Nature, 173 (1954):449.

812 Olsen, R.D., Scott’s Fingerprint Mechanics, Charles C. Thomas, Springfield, Il., 1978
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813 Annex B

814 (informative)

815 Bibliography

816 1] http://www.swgtread.org/images/documents/standards/published/swgtread_14_enhanceme

817 nt_chemical_200809.pdf

818 2] Bleay, S.M., Sears, V.G., Bandey, H.L., Gibson, A.P., Bowman, V.J., Downham, R., Selway, C., Finger 

819 Mark Development Techniques within Scope of ISO 17025. Fingerprint Source Book, Chapter 3, 

820 United Kingdom- Home Office, 2013

821 3] Bodziak, W.J. Footwear Impression Evidence: Detection, Recovery, and Examination. 2nd Ed. Boca 

822 Raton, FL: CRC Press; 2000.

823 4] Bodziak, W.J., Forensic Footwear Evidence, CRC Press, 2017

824 5] Bodziak, W.J., Use of Leuco-Crystal Violet to Enhance Shoe Prints in Blood, Forensic Science 

825 International, 82(1): 45-52, 1996 

826 6] Bouwmeester, M., Gorre, S., Rodriguez, C., de Puit, M., A Comparison of Reagents for the 

827 Visualization of Blood Prints on Knives with Black Handles, Journal of Forensic Identification, 

828 61(4): 353-362, 2011

829 7] Cassidy, M., Footwear Identification, Royal Canadian Mounted Police, 1980

830 8] Cheeseman, R., Direct Sensitivity Comparison of the Fluorescein and Luminol Bloodstain 

831 Enhancement Technique, Journal of Forensic Identification, 49(3): 631-646, 1995 

832 9] Farrugia, K.J., Bandey, H., Dawson, L., NicDaeid, N., A Comparison of Enhancement Techniques for 

833 Footwear Impressions on Dark and Patterned Fabrics, Journal of Forensic Sciences, 58(6): 1472-

834 1485, 2013

835 10] Farrugia, K.J., Savage, K., Bandey, H., NicDaeid, N., Chemical Enhancement of Footwear 

836 Impressions in Blood on Fabric- Part 1: Protein Stains, Science and Justice, 51(3): 99-109, 2011 

837 11] Farrugia, K.J., Savage, K., Bandey, H., Ciuksza, T., NicDaeid, N., Chemical Enhancement of Footwear 

838 Impressions in Blood on Fabric- Part 2: Peroxidase Reagents, Science and Justice, 51(3): 110-121, 

839 2011

840 12] Farrugia, K.J., Savage, K., Bandey, H., NicDaeid, N., Chemical Enhancement of Footwear 

841 Impressions in Blood on Fabric- Part 3: Amino Acid Staining, Science and Justice, 53(1): 8-13, 

842 2013

843 13] Froude, J.H. Using Ammonium Thiocyanate and Potassium Thiocyanate, Journal of Forensic 

844 Identification, 48(6):718 -724, 1998

845 14] Hussain, J., Pounds, C., The Enhancement of Marks in Blood, Central Research Establishment 

846 Report, No. 649, 1988 
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847 15] Larkin, T., Gannicliffe, C., Illuminating the Health and Safety of Luminol, Science and Justice, 48(2): 

848 71-75, 2008 

849 16] Lee, H.C., Gaensslen, R.E., Advances in Fingerprint Technology, 2nd Edition, 2001

850 17] Lytle, L.T., Hedgecock, D., Chemiluminescence in the Visualization of Forensic Bloodstains, 

851 Journal of Forensic Sciences, 23(3): 550-562, 1978

852 18] Manual of Fingerprint Development Techniques 2nd. Edition, Home Office Police Scientific 

853 Development Branch, White Crescent Press, Ltd., Luton, England, 2001

854 19] Processing Guide for Developing Latent Prints, Federal Bureau of Investigation, 2000

855 20] Sears, V.G., Prizeman, T.M., Enhancement of Fingerprints in Blood- Part 1: The Optimization of 

856 Amido Black, Journal of Forensic Identification, 50(5): 470-480, 2000

857 21] Sears, V.G., Butcher, C.P., Prizeman, T.M., Enhancement of Fingerprints in Blood- Part 2: Protein 

858 Dyes, Journal of Forensic Identification, 51(1): 28-38, 2001 

859 22] Sears, V.G., Butcher, C.P.G., Fitzgerald, L.A., Enhancement of Fingerprints in Blood, Part 3: Reactive 

860 Techniques, Acid Yellow 7 and Process Sequences, Journal of Forensic Identification, 55(6): 741-

861 763, 2005

862 23] Theeuwen, A.B.E., van Barnevald, S., Drok, J.W., Keereweer, I., Lesger, B., Limborgh, J.C.M., Naber, 

863 W.M., Schrok, R., Velders, T., Enhancement of Muddy Footwear Impressions, Forensic Science 

864 International, 119: 57 -67, 2001

865 24] Theeuwen, A.B.E., van Barneveld, S., Drok, J.W., Keereweer, I., Limborgh, J.C.M., Naber, 

866 W.M., Velders, T., Enhancement of Footwear Impressions in Blood, Forensic Science 

867 International, 95: 133 -151, 1998

868

869 25] Velders, T. New Insight into the Chemical Enhancement of Shoeprints in Blood on Non-Porous 

870 Surfaces. Identification Canada, 35(3): 80-102, 2012.