OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

1

OSAC 2023-N-0020

Standard for the On-Scene 

Collection and Preservation of 

Friction Ridge Impressions

Crime Scene Investigation & Reconstruction Subcommittee

Scene Examination Scientific Area Committee

Organization of Scientific Area Committees (OSAC) for Forensic Science
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

2

Draft OSAC Proposed Standard

OSAC 2023-N-0020

Standard for the On-Scene Collection 

and Preservation of Friction Ridge 

Impressions 

Prepared by 

Crime Scene Investigation & Reconstruction Subcommittee

Version: 1.0

June 2023

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.
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

1

1 Foreword

2 Proper collection and preservation of friction ridge impressions ensure that the integrity of the 

3 evidence is maintained from the point of collection, through possible forensic examination, and 

4 to the presentation of the evidence in the courtroom. This document delineates standards and 

5 recommendations for collecting and preserving friction ridge impressions. The methods in this 

6 standard are intended to maintain the integrity of friction ridge impressions so that reliable, 

7 accurate, and relevant conclusions can be obtained. This document should be utilized in 

8 conjunction with regulations to inform or augment applicable policies.

9 This document should be utilized in conjunction with local regulations and any requirements set 

10 forth by entities examining collected evidence to inform or augment policies relating to 

11 collecting and preserving physical evidence. 

12 This document has been drafted by the Crime Scene Investigation and Reconstruction 

13 Subcommittee of the Organization of Scientific Area Committees (OSAC) for Forensic Science 

14 through a consensus process.

15 This standard provides guidance on some safety issues but is not exhaustive. It is the 

16 responsibility of the appropriate agency to develop a full health and safety plan. All hyperlinks 

17 and web addresses shown in this document are current as of the publication date of this standard.

18 All hyperlinks and web addresses shown in this document are current as of the publication date 

19 of this standard.

20

21

22

23

24

25

26

27

28

29

30 Keywords: scene investigation, collection, preservation, detection, development, friction ridge 

31 impressions, latent impressions, patent impressions, plastic impressions, processing methods
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

2

32 Table of Contents

33 1. Scope 1

34 2. Normative References 1

35 3. Terms and Definitions 1

36 4. General Collection and Preservation of Friction Ridge Impressions 3

37 4.1 Preservation of Friction Ridge Impressions 3

38 5. Development and Enhancement of Friction Ridge Impressions 3

39 5.1 Development Techniques 4

40 5.2 Processing Order 4

41 5.3 Friction Ridge Processing Methods 4

42 6. Latent Impressions 5

43 6.1 Detection 5

44 6.2 Documentation 5

45 6.3 Enhancement 5

46 6.4 Collection 5

47 7. Patent Impressions 5

48 7.1 Detection 6

49 7.2 Documentation 6

50 7.3 Enhancement 6

51 7.4 Collection 6

52 7.5 Techniques and Enhancements for patent blood impressions 6

53 8. Plastic Impressions 7

54 8.1 Detection 7

55 8.2 Documentation 7

56 8.3 Enhancement 7

57 8.4 Collection 7

58 9. Friction Ridge Processing Methods 7

59 9.1 Surfaces 8

60 9.2 Methods 8

61 10. Friction Ridge Collection and Preservation 12

62 10.1 Photography 12
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

3

63 10.2 Lifting 12

64 10.3 Difficult Surfaces 13

65 Annex A (informative) Sequential Processing Chart 14

66 Annex B (informative) Bibliography 15

67

68
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

1

69 1. Scope

70 This document delineates standards and recommendations for collecting and preserving friction 

71 ridge impressions. This document does not apply to the collection of known impressions or the 

72 process of source attribution.

73 2. Normative References

74 The following reference is indispensable for the application of the Standard. For dated 

75 references, only the edition cited applies. The latest edition of the referenced document 

76 (including any amendments) applies for undated references.

77 OSAC 2021-N-0015, Guiding Principles for Scene Investigation and Reconstruction 

78 See Annex A, (informative) Bibliography, for other references.

79 3. Terms and Definitions

80 For purposes of this document, the following definitions and acronyms apply:

81 NOTE: In a situation that involves a potentially criminal act, definitions in sections 3.1 through 

82 3.14 would be preceded by "crime" (e.g., crime scene investigator).

83 3.1

84 contamination

85 The undesirable introduction of a substance to an item at any point in the forensic 

86 process. (ISO/FDIS 21043-1:2018[E])

87 NOTE This includes the undesirable transfer of a substance within an item or between items, 

88 also referred to as cross-contamination. 

89 3.2

90 detection

91 The process of identifying the presence of friction ridge impressions.

92 3.3

93 development

94 The process of making an impression visible and, in most cases, is also the equivalent of locating 

95 the impression. 

96 3.4 

97 examination quality photograph

98 A photograph taken following a specific protocol for the purpose of conducting a comparative 

99 forensic examination.

100 3.5

101 friction ridge collection
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

2

102 The process of transitioning a developed friction ridge impression into a tangible form for 

103 transport and laboratory analysis. Collection may or may not be the same as preservation.

104 3.6

105 friction ridge impression

106 An impression from the palmar surfaces of the hands or fingers or from the plantar (sole) 

107 surfaces of the feet or toes. (OSAC Lexicon)

108 3.7

109 friction ridge processing 

110 The procedure of performing a series of techniques to visualize the impression of the raised 

111 portion of the epidermis on a surface. 

112 3.8 

113 friction ridge preservation

114 The process of maintaining the impression in the best possible condition.

115 3.9

116 forensic light source (FLS)

117 A filtered light source that may be fixed or tunable to a variety of spectral ranges. (OSAC 

118 Lexicon)

119 3.10

120 processing method

121 Any technique for friction ridge enhancement.

122 3.11

123 scene

124 A place or object that is subject to and/or requires forensic examination. (ISO/FDIS 21043-

125 1:2018)

126 NOTE A crime scene is a common description of a scene where a presumed crime has been 

127 committed. The scene can also be a person or an animal.

128 3.12

129 scene investigation 

130 The act of identifying, documenting, preserving, and collecting physical evidence from a scene. 

131 3.13

132 scene investigator 

133 An individual, however, named, who is responsible for performing elements of a scene 

134 investigation that may or may not involve a potentially criminal act.

135 3.14

136 technique

137 The method for carrying out a particular task.

138
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

3

139 4. General Collection and Preservation of Friction Ridge Impressions

140 Friction ridge impressions are unique and persistent throughout a lifetime, absent an injury to the 

141 skin or upon decomposition after death. Friction ridge impressions are chance impressions that 

142 can be left on a surface in the form of fingerprints, phalanx (joint) impressions, palm prints, or 

143 plantar (foot) impressions. When friction ridge skin comes into contact with a surface, an 

144 impression or a portion thereof may be left behind that may be compared to a specific source. 

145 Friction ridge impressions may be visible to the naked eye or may need various development and 

146 enhancement methods in order to be observed and collected. The three categories of friction 

147 ridge impressions are latent, patent, and plastic.

148 There are several factors involved in the deposition and development of friction ridge 

149 impressions, which include, but are not limited to: skin conditions, environmental factors, 

150 handling of the evidence at the time of collection, and the manner in which the evidence is 

151 packaged.

152 These methods often depend upon the impression's composition and the surface on which it is 

153 deposited. Reagents and developmental techniques for friction ridge impressions are generally 

154 intended to be used in combination and in sequential order. Adherence to correct processing 

155 methods increases the probability of developing the best quality friction ridge impression and

156 minimizes the potential of destroying impressions and/or evidence upon which they were 

157 deposited. The collection method employed for a friction ridge impression will be dependent on 

158 the development method utilized. The investigator should consider additional evidence 

159 collection, such as DNA and trace evidence, before selecting a friction ridge processing method. 

160 In some circumstances, it may be better to collect an item for more extensive friction ridge 

161 processing in a controlled laboratory environment rather than attempting to process the item on 

162 scene.

163 OSAC 2021-N-0015, Guiding Principles for Scene Investigation and Reconstruction, shall be 

164 used in conjunction with this document because OSAC 2021-N-0015 provides the foundational 

165 principles upon which additional specific requirements, such as this document, will be based.

166 4.1 Preservation of Friction Ridge Impressions

167 4.1.1 Friction ridge impressions shall be handled, collected, packaged, and preserved in a 

168 manner that prevents contamination, tampering, alteration, or loss of evidence. 

169 NOTE: The use of gloves does not always prevent the transfer of friction ridge detail from the 

170 analyst to the evidence.

171 4.1.2 To prevent damage to friction ridge impressions, items should be handled in areas not 

172 normally touched or on surfaces incapable of yielding legible ridge detail (e.g., the 

173 textured surfaces of handguns). 

174 4.1.3 If processing can result in the destruction of the friction ridge impressions, the scene 

175 investigator should consult with a specialist. 
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

4

176 5. Development and Enhancement of Friction Ridge Impressions

177 It is important to note that not all processes are used in every situation. Discretion in the choice 

178 of development and enhancement techniques will remain with individual agencies and 

179 practitioners both at the scene and in the laboratory.

180 The following are examples of factors that can influence the choice of development techniques:

181 ● Type of friction ridge residue suspected (e.g., blood, oil, sweat)

182 ● Type of substrate

183 ● Texture of surface

184 ● Condition of surface (e.g., clean, dirty, tacky, sticky, greasy) 

185 ● Environmental conditions during and following friction ridge deposition 

186 ● Location of processing

187 ● Length of time since the evidence was handled

188 ● Consequences of destructive processing methods 

189 ● Subsequent forensic examinations (e.g., DNA or chemical analysis) 

190 ● Sequential ordering of reagents 

191 5.1 Development Techniques 

192 5.1.1 Friction ridge impression development can be achieved with a wide array of optical, 

193 physical, and chemical processes. If viable ridge detail is visibly present, documentation 

194 should be completed before additional developmental techniques are implemented. 

195 Friction Ridge Impressions should be documented at each stage of processing.

196 5.2 Processing Order

197 5.2.1 Processing should generally begin with the least destructive technique. Visual inspection 

198 and the least intrusive methods should be utilized prior to the use of any methods that can 

199 alter the impression or substrate. Visualization of friction ridge impressions through the 

200 use of optical or lighting methods is considered non-destructive and should be attempted 

201 prior to each subsequent processing method. Refer to Appendix B for an outline of 

202 processing methods. 

203 NOTE: Forensic Light Sources, particularly near the UV range, can damage DNA.

204 5.3 Friction Ridge Processing Methods
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

5

205 a) Friction Ridge Processing can encompass dusting and other enhancement methods.

206 b) Friction Ridge Processing is used to develop friction ridge impressions through a 

207 chemical reaction that occurs between the impression residue components and the 

208 selected reagent. Residue can be secreted through eccrine or sebaceous components. 

209 Other residues can be deposited on friction ridge skin, such as blood, paint, etc. 

210 i. Reagent checks should be performed and documented based on departmental 

211 policies prior to the use of evidence. 

212 ii. Adherence to recommended friction ridge processing techniques ensures the best 

213 opportunity to develop all friction ridge detail on an object and minimizes the 

214 chance of destroying the friction ridge impressions.

215 6. Latent Impressions

216 A latent impression (i.e., impression) is one where the ridge detail is not visible to the unaided 

217 eye and requires additional processing to observe and collect ridge detail. 

218 6.1 Detection

219 Some latent impressions are transient and are subject to environmental conditions. Locations and 

220 evidence should be examined as soon as feasible with appropriate optical (i.e., lighting 

221 techniques such as the forensic light source (FLS)), physical, or chemical processes designed to 

222 enhance the contrast of friction ridge impressions. 

223 6.2 Documentation

224 6.2.1 Latent impressions should be documented at each stage of processing and before 

225 collection. Scene notes should be taken outlining the locations, compositions, orientation, 

226 and features of any discovered impressions.

227 6.2.2 The scene investigator should document the technique(s) used to capture the impression 

228 to aid the examiner in determining if the image is reversed. 

229 6.3 Enhancement

230 6.3.1 Most latent impressions can be enhanced using physical and chemical processes. If the 

231 item can be processed at the scene, the scene investigator should apply the appropriate 

232 development technique. If possible, the item should be enhanced in a controlled 

233 environment. 

234 NOTE: See the Friction Ridge Processing Methods section below.

235 6.4 Collection
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

6

236 6.4.1 If possible, the scene investigator should collect the item, and the item should be 

237 processed in a controlled environment. If the item is processed at the scene, the ridge 

238 detail should be collected using appropriate methods, such as a photograph and/or lift. 

239 7. Patent Impressions

240 A patent impression is one where the ridge detail is partially or wholly visible to the unaided eye. 

241 Examples include but are not limited to an impression in blood, paint, ink, mud, or dust. 

242 7.1 Detection

243 7.1.1 Some visible impressions are transient and are subject to temporary or environmental 

244 conditions. Locations and evidence should be examined for patent impressions as soon as 

245 feasible. A variety of lighting techniques may assist in the visualization and may enhance 

246 the contrast of the friction ridge impressions.

247 7.2 Documentation

248 7.2.1 Patent impressions should be documented through photography. Scene notes should be 

249 taken outlining the locations, orientation, compositions, and features of any discovered 

250 impressions.

251 7.3 Enhancement

252 7.3.1 Most patent impressions can be enhanced using similar processing methods to those of 

253 latent impressions.

254 NOTE: See the Friction Ridge Processing Methods section below. 

255 7.4 Collection

256 7.4.1 An item containing a patent impression should be photographed before collection. 

257 a. After photography, if possible, the complete item should be collected. 

258 b. If collection is not possible, the relevant section of the item containing the impression 

259 should be collected.

260 7.5 Techniques and Enhancements for patent blood impressions

261 7.5.1 Friction ridge impressions in blood can be produced when blood is transferred from a 

262 subject to a surface or when friction ridges come into contact with existing blood.

263 7.5.2 Universal precautions should be employed when handling items with suspected 

264 biological pathogens, such as blood or other potentially infectious material. 

265 7.5.3 Friction ridge impressions in blood and other biological substances should be enhanced in 

266 a manner that minimizes the possibility of contaminating a DNA profile. It is up to the 
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

7

267 discretion of the scene investigator to determine if DNA samples should be collected 

268 before proceeding with friction ridge development.

269 7.5.4 Forensic light sources (FLS) can be used for creating sharper background contrast and 

270 enhancing ridge detail visualization and are considered the least destructive method of 

271 development. Chemical enhancements using stains, tests, and protein dyes, such as 

272 Amido Black and Leucocrystal Violet, can also be used to further visualize blood and 

273 blood-based ridge detail.

274 NOTE: Some chemical enhancements, such as luminol, can potentially damage the friction ridge 

275 detail and are not recommended for enhancement of friction ridge impressions in blood. 

276 8. Plastic Impressions

277 A plastic impression is formed by the contact of friction ridge skin with a soft or pliable 

278 substance (e.g., wax, putty, etc.) that subsequently retains a three-dimensional image of the 

279 impression. 

280 8.1 Detection

281 8.1.1 Locations and evidence should be examined for plastic impressions as soon as feasible. 

282 Oblique lighting may be needed to detect ridge detail. Some plastic impressions are 

283 transient and are subject to temporary or environmental conditions.

284 8.2 Documentation

285 8.2.1 Plastic impressions should be documented through photography. The investigator should 

286 document the technique(s) used to capture the impression to aid the examiner in 

287 determining if the image is reversed. 

288 8.3 Enhancement

289 8.3.1 Various lighting techniques can be used to visualize the ridge detail of plastic 

290 impressions. 

291 8.4 Collection

292 8.4.1 An item containing a plastic impression should be photographed prior to collection. The 

293 use of a silicone casting material can be used to collect plastic impressions if the item is 

294 unable to be collected. 

295 NOTE: Some chemical enhancements, such as luminol, can potentially damage the friction ridge 

296 detail and are not recommended for enhancement of friction ridge impressions in blood. 

297 9. Friction Ridge Processing Methods
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

8

298 The processing method will be determined based on the surface upon which the friction ridge 

299 impression is located. Surfaces can be separated into three classes: Non-Porous, Porous, or Semi300 Porous.

301 Many items of evidence consist of more than one physical property (e.g., a porous envelope with 

302 a glassine window). In those situations, the scene investigator should apply the processing 

303 methods using sequences appropriate for the relevant areas in a manner that does not negatively 

304 impact other areas of the evidence.

305 9.1 Surfaces

306 9.1.1 Non-Porous surfaces typically are non-absorbent and repel moisture. Non-porous 

307 surfaces may also appear polished. Examples include rubber, glass, metal, and lacquered 

308 or painted wood. 

309 9.1.2 Porous surfaces typically are absorbent and do not repel moisture. Examples include 

310 paper, cardboard, and wood. 

311 9.1.3 Semi-porous surfaces are typically characterized by the ability to both repel and absorb 

312 moisture depending on the absorbency of the surface. Examples include glossy 

313 cardboard, glossy magazine covers, cellophane, latex gloves, and some finished wood. 

314 9.2 Methods

315 9.2.1 Non-porous, Porous, and Semi-porous surfaces containing ridge detail can be further 

316 processed using a variety of physical and chemical processes. This document discusses 

317 some of those processing methods but does not include a discussion on all processing 

318 methods. 

319 9.2.2 Processing methods that will be discussed are: powder, cyanoacrylate processing, dye 

320 stains, small particle reagent, adhesive-side powder, 1,8-Diazafluoren-9-one (DFO), 

321 ninhydrin, and 1,2 indanedione. 

322 NOTE: Refer to Appendix B for a sequential processing chart

323 a. A positive control should be utilized to ensure the functionality of any processes used

324 b. The scene investigator should consider photographing or scanning items before and after 

325 the application of the processing methods to record changes resulting from the processing 

326 methods. 

327 c. If background interference is a concern when selecting a physical or chemical processing 

328 method, an area of the surface away from the friction ridge impression should be tested.

329 d. An FLS can assist in visualizing impressions that are not visible with other processing 

330 methods.
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

9

331 e. The FLS may be used on any surface in which a fluorescing reagent/process has been 

332 used and needs to be visualized, such as fluorescent powders and dye stains. The FLS 

333 should not be used without viewing through the proper filters/goggles, as the scene 

334 investigator may not be able to visualize the fluorescence, and eye injury may occur.

335 9.2.3 Powder processing 

336 i.Powder Processing is a physical method in which powder particles adhere to residues in 

337 the friction ridge impression.

338 a. A variety of powder processing methods can be utilized, such as magnetic or non339 magnetic, both available in a variety of colors (including fluorescent). 

340 b. The scene investigator should choose a brush (e.g., magnetic or non-magnetic such as 

341 fiberglass, feather, camel hair, etc.) based on the type of powder(magnetic or non342 magnetic powder) being used and the surface of the object. Disposable brushes and 

343 powders should be used in cases where cross-contamination of DNA is a concern. 

344 c. The scene investigator should dispense the powder into a secondary container and apply 

345 the powder with a brush to the surface of the object.

346 d. Apply the powder in a circular motion, with only the brush touching the surface. As 

347 friction ridges begin to develop, brush in the direction of the ridge flow. 

348 ii. When using the magnetic brush, engage the magnet to adhere powder to the end 

349 of the brush and apply the powder to the surface for ridge development without 

350 allowing the magnetic wand to make contact with the surface. When the magnet is 

351 disengaged, the powder is released from the wand. The scene investigator should 

352 not use magnetic powder on iron-containing surfaces. 

353 iii. When using a non-magnetic brush, the scene investigator should avoid placing the 

354 brush directly into the original powder container to not contaminate the powder. 

355 e. After documenting the friction ridge impressions with photography, the scene 

356 investigator should use a lifter (e.g., hinge lifter, gel lifter, tape, etc.) to remove the 

357 developed ridge detail from the surface. 

358 f. The scene investigator should place the developed ridge detail on a backing card that 

359 creates contrast and document details of the lift: case information, date, location of lift, 

360 orientation, etc. 

361 g. If the ridge detail is unable to be lifted, the scene investigator should photograph the ridge 

362 detail and collect the item or cut a section from the surface.

363 9.2.4 Cyanoacrylate processing

364 i.Cyanoacrylate, also known as superglue fuming, is a preservation technique sensitive to 

365 components of friction ridge impressions. Basic equipment includes an enclosure, 
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

10

366 humidifier, aluminum dish, a heat source, and cyanoacrylate. Proper ventilation is 

367 required for containment and to minimize the risk of exposure. 

368 a. Preparation

369 i. Place the items for development in the enclosure in a manner that will allow for 

370 the free flow of air around the item. 

371 ii. Place liquid cyanoacrylate in the aluminum dish. 

372 iii. Place the aluminum dish on a heating surface in the enclosure and add a positive 

373 control (i.e., test print) for visualization into the chamber. 

374 iv. Activate your heating element, and if a humidified enclosure is available, set the 

375 humidity between 70% and 80% for best results. 

376 v. Secure or seal the enclosure and fume the items.

377 b. Timing

378 i. Fuming time varies depending on the size of the enclosure, the item, and your 

379 equipment. The scene investigator should visually monitor impression 

380 development through positive controls to ensure the item is not over-processed. 

381 ii. After the fuming cycle is complete, the scene investigator should ensure adequate 

382 ventilation of the vapors before removing items from the enclosure.

383 iii. Items should then be removed from the enclosure and viewed for possible ridge 

384 detail. 

385 iv. If necessary, the fuming process can be repeated.

386 c. The developed friction ridge detail can be collected and preserved by photography. 

387 i. Different lighting techniques can be utilized, including oblique, reflected, and 

388 transmitted lighting techniques, to enhance visualization. 

389 ii. Powders and dye stains may be applied to enhance the contrast between the 

390 friction ridge and the surface. Refer to Appendix B for the Sequential Processing 

391 Chart.

392 9.2.5 Dye Stains 

393 ii.Dye stains are effective for enhancing ridge detail developed with cyanoacrylate. Dye 

394 stains can be applied through various methods and aid the scene investigator in further 

395 visualizing ridge detail. Dye stains include, but are not limited to, Basic Yellow 40, 

396 Rhodamine 6G (R6G), Ardrox, and RAM. 
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

11

397 a. The scene investigator should select the dye stain that will create the greatest ridge 

398 contrast with the background surface. 

399 b. Impressions that are inherently fluorescent or have been processed with a fluorescent 

400 powder or dye stain, should be photographed using light from the forensic light source 

401 (no ambient light) and an appropriate filter on the camera. If using UV light, a barrier 

402 filter would not be needed.

403 9.2.6 Small Particle Reagent (SPR) 

404 iii.SPR can be used for the development of friction ridge detail on wet, non-porous surfaces 

405 and adhesive tape surfaces. SPR can also be effective on liquid accelerant-soaked 

406 surfaces. SPR can be applied through a spray method or a dish method. SPR may also be 

407 used for post-cyanoacrylate processing. 

408 a. Ridge detail developed with SPR can be lifted or photographed for collection purposes. 

409 The scene investigator should immediately photograph the results of SPR processing, 

410 regardless of the collection method, due to the fragile nature of the solution. After 

411 photography, the developed ridge detail can be preserved with lifters. 

412 9.2.7 Adhesive Side Powder

413 a. The scene investigator should consider the color of the adhesive side of the surface before 

414 selecting a processing technique to obtain the greatest contrast. Dark-colored adhesive 

415 surfaces may include but are not limited to masking, duct, or electrical tape. Light416 colored adhesive surfaces may include but are not limited to packing tape, surgical tape, 

417 or painter's tape.

418 b. The scene investigator should visually examine the adhesive surface with a light and an 

419 FLS. After visual examination, the scene investigator should determine which color 

420 sticky side powder to be used. 

421 c. The sticky side powder is painted on the adhesive surface of the tape with a camel-hair 

422 brush. The scene investigator should allow the sticky side powder to settle for 30 to 60 

423 seconds before rinsing it off with a slow stream of cold tap water. Allow the item to dry. 

424 The procedure can be repeated if needed. 

425 d. Ridge detail developed with sticky side powder should be photographed for collection 

426 and preservation. The scene investigator should submit the adhesive surface containing 

427 the ridge detail for evaluation. The scene investigator should consider processing 

428 techniques for the surface of the non-adhesive side of the tape to determine proper 

429 sequencing.

430 9.2.8 DFO,1,2 Indandione, and Ninhydrin 

431 iv.DFO,1,2 Indandione, and Ninhydrin are reagents that react with amino acids. Friction 

432 ridge impressions may be created by the deposition of sweat when friction ridge skin 

433 comes into contact with a surface. Sweat contains amino acids, and when friction ridge 
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

12

434 skin comes into contact with porous or semi-porous items, amino acids are absorbed into 

435 the surface. Amino acids are deposited on porous or semi-porous surfaces, such as paper, 

436 checks, letters, cardboard, etc. 

437 a. The scene investigator should visually examine the porous or semi-porous item to 

438 determine which reagent should be used. 

439 b. Ridge detail developed with these reagents should be photographed for collection and 

440 preservation. 

441 c. The scene investigator should submit the porous or semi-porous surface containing the 

442 ridge detail for evaluation. 

443 d. The scene investigator should consider the destruction of any inks on the surface of the 

444 items prior to applying the reagents. 

445 10. Friction Ridge Collection and Preservation

446 10.1 Photography

447 10.1.1 Friction ridge impressions should be photographed before they are collected because they 

448 can be damaged or destroyed when lifted.

449 a. Photographs should be taken in a non-compressed file format, such as a RAW or TIFF 

450 format. 

451 b. Location and orientation photographs should be taken of the friction ridge impression 

452 prior to close-up photographs. 

453 c. A tripod or copy stand should be used. 

454 d. In close-up photographs, the film/digital sensor plane should be parallel to the friction 

455 ridge impression. 

456 e. A scale should be placed next to the impression, and both the scale and the impression 

457 should fill the frame of the photograph.

458 f. Uneven or curved surfaces require greater depth of field (and/or focus stacking 

459 techniques).

460 g. A variety of lighting techniques should be utilized to capture the best friction ridge detail, 

461 including oblique, reflected, transmitted, and FLS. 

462 h. Impressions that are inherently fluorescent or have been processed with a fluorescent 

463 powder or dye stain, should be photographed using light from the forensic light source 

464 (no ambient light) and an appropriate filter on the camera. If using UV light, a barrier 

465 filter would not be needed.
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

13

466 10.2 Lifting

467 10.2.1 Depending on the development process utilized, friction ridge impressions can be lifted 

468 from surfaces after photography using a variety of different methods to make a 

469 permanent record which can be used for comparison to known impressions or entered 

470 into AFIS. Substances that can be lifted include, but are not limited to, powder, dust, and 

471 pollen. Patent impressions may need additional processing before lifting. 

472 a. To collect friction ridge impressions, the scene investigator should use a lifting medium, 

473 such as clear tape, hinge, or lifters. 

474 b. For best results, the scene investigator should wear gloves and anchor one side of the tape 

475 or lifter onto the surface next to the ridge detail and then slowly roll the tape or lifter onto 

476 the surface using even pressure to ensure that it adheres fully to the surface. 

477 c. For curved surfaces, it may be best to place the lifting medium on the center of the ridge 

478 detail and smooth outward.

479 d. The tape or lifter should be removed in a smooth motion to prevent start/stop lines from 

480 appearing on it. The tape or lifter should then adhere to a suitable lift backing. 

481 e. The lift backing should be labeled with, at a minimum, the case number, the date the 

482 impression was lifted, the scene investigator who lifted it, an identifying number, and the 

483 location, description, and orientation of where the impression was lifted.

484 10.3 Difficult Surfaces

485 10.3.1 Silicone-based casting materials may be used to lift friction ridge impressions from 

486 difficult surfaces, such as textured or curved surfaces, to obtain a three-dimensional, 

487 permanent flexible mold. The scene investigator should refer to the manufacturer's 

488 instructions for the application technique. The recovered lift should be placed into a 

489 properly labeled evidence envelope for preservation. 

490
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

14

491 Annex A

492 Sequential Processing Chart

493 *SGF=Superglue Fuming (Cyanoacrylate)

494 NOTE: Guidance related to application, formulation, and optimization of specific processing 

495 techniques can be found in the Fingerprint Source Book.

496 vi.

497 vii.

498
OSAC 2023-N-0020 Standard for the On-Scene Collection

and Preservation of Friction Ridge Impressions 

15

499 Annex B

500 (informative)

501 Bibliography

502

503 This is not meant to be an all-inclusive list, as the group recognizes other publications on this 

504 subject may exist. When this document was drafted, these were some of the publications 

505 available for reference. Also, any mention of a particular software tool or vendor as part of this 

506 bibliography is purely incidental, and any inclusion does not mean that the authors of this 

507 document are endorsing it.

508 1] National Institute of Justice, The Fingerprint Sourcebook. Washington, DC: U.S. Dept. of 

509 Justice, Office of Justice Programs, National Institute of Justice, 2011.

510 2] Organization for Scientific Area Committees for Forensic Science. OSAC Lexicon.

511 https://lexicon.forensicosac.org/

512 3] Organization for Scientific Area Committees for Forensic Science. Guiding Principles for 

513 Crime Scene Investigation and Reconstruction. OSAC 2021-N-0015. 2021. 

514 4] Organization for Scientific Area Committees for Forensic Science. Standard for On-Scene 

515 Collection and Preservation of Physical Evidence, proposed standard.

516 5] United States Federal Bureau of Investigation. The Science of Fingerprints: Classification and 

517 Uses. Project Gutenberg, 2014.