Weakly alkaline ascorbic acid developing composition, processing kit and method using same

A black-and-white developing composition includes as ascorbic acid developing agent, an auxiliary super-additive developing agent, borate buffer and a preservative. The composition pH is from 7 but less than 9. The composition can be formulated from two separately packaged parts that may be in dry or liquid form. The borate buffer is present to maintain the desired pH, and the two developing agents are present in desired molar ratios for optimal developing activity. Improved photographic properties are obtained while avoiding the use of environmentally unfriendly dihydroxybenzenes.

FIELD OF THE INVENTION 
This invention relates in general to photography and in particular to an 
improved ascorbic acid black-and-white developing composition that is free 
of dihydroxybenzene developing agents. It also relates to a developing kit 
and a method of using the developing composition. 
BACKGROUND OF THE INVENTION 
Photographic developing compositions containing a silver halide developing 
agent are well known in the art for reducing silver halide grains 
containing a latent image to yield a developed photographic image. Many 
useful developing agents are known in the art, with hydroquinone and 
similar dihydroxybenzene compounds being some of the most common. 
While dihydroxybenzenes (such as hydroquinone) generally provide 
development, with or without various known booster and nucleating 
compounds or auxiliary developing agents, they are disadvantageous from 
technical, ecological and environmental considerations. For example, 
hydroquinone solutions are not completely stable in air, being prone to 
aerial oxidation. The by-products of the instability are often insoluble, 
black, tarry materials that contaminate the processing solutions and 
equipment. 
The oxidation of hydroquinones also leads to higher pH which in turn leads 
to increased developer activity. Images can be thusly produced faster, so 
the processing time must be reduced. The net effect is less control of the 
process, and less desirable sensitometric properties in the processed 
materials. 
In addition, hydroquinones have become of increasing concern in recent 
years from the point of view of potential toxicity and environmental 
pollution. 
Another class of developing agents described in several publications, 
including U.S. Pat. No. 5,236,816 (Purol et al.), include ascorbic acid 
and various derivatives and salts thereof. Although developing 
compositions containing ascorbic acid are more environmentally friendly, 
they generally are at higher pH (at least 9.5), and contain various 
components that can also place considerable oxygen demand on the 
environment. 
Moreover, most developing compositions are formulated as concentrated 
liquid solutions so the user must dilute them to working strength. Such 
solutions cannot be concentrated significantly, because of the various 
components therein, without the use of auxiliary solvents that are 
preferably to be avoided. 
One way to reduce the packaging needs is to formulate the composition as a 
pre-measured solid. The user then dissolves the solid composition in the 
proper amount of water to provide a developer solution. In practice, this 
presents major problems in processing continuous tone black-and-white 
camera speed films. Because of the low pH of these solutions (7 to 9), the 
solid compositions are often not readily soluble in water at ambient 
temperature, and thus must be heated considerably to effect complete 
solution. The higher temperature however increases aerial oxidation of the 
developing agent and formation of undesirable by-products. Moreover, this 
is quite time consuming for the heating and subsequent cooling of the 
solutions. 
Yet there is a desire to be able to formulate such compositions in either 
dry or aqueous form while avoiding the problems noted above. It would also 
be preferable to minimize packaging and to provide a solid formulation 
that does not need to be heated to complete solubility and which does not 
diminish photographic properties of the processed black-and-white camera 
speed films. 
Although there have been some attempts to solve these problems in the art 
with ascorbic acid type developing agents, the results have not been 
totally satisfactory. For example, U.S. Pat. No. 5,098,819 (Knapp) 
describes the use of ascorbic acid developing solutions containing 
carbonate buffer to maintain the pH at from 9.75 to 10.6. This pH range is 
not desirable, and the reference does not address the solubility problems 
encountered with solid formulations formulated for lower pH. Similar 
liquid developer formulations are also described in U.S. Pat. No. 
5,498,511 (Yamashita et al.), U.S. Pat. No. 5,384,232 (Bishop et al.) and 
EP-A-0 603 586 (Parker et al.) which are directed to graphic arts imaging 
as opposed to continuous tone camera speed films. 
There is a need to provide a black-and-white developing composition that 
does not have the problems noted above, and that can be formulated in dry 
or aqueous form. 
SUMMARY OF THE INVENTION 
The present invention overcomes the problems noted above with an aqueous 
black-and-white developing composition that is free of dihydroxybenzene 
developing agents, the developing composition having a pH of greater than 
7 but less than 9, and comprising: 
an ascorbic acid developing agent, 
an auxiliary super-additive developing agent, 
borate as the sole buffer in an amount of at least 0,001 mol/l and 
a preservative, 
wherein the molar ratio of the ascorbic acid developing agent to the 
auxiliary super-additive developing agent is at least about 10:1. 
This invention also provides a photographic black-and-white developing kit 
having first and second separately packaged formulations, at least one 
formulation being packaged in dry form, and each formulation being free of 
dihydroxybenzene developing agents: 
wherein the first packaged formulation comprises an ascorbic acid 
developing agent, and a first preservative, wherein the molar ratio of the 
first preservative to the ascorbic acid developing agent is at least 4:1, 
and 
the second packaged formulation comprises an auxiliary super-additive 
developing agent, and a second preservative, wherein the molar ratio of 
the second preservative to the auxiliary super-additive developing agent 
is at least 4:1, 
provided that when the first and second packaged formulations are dissolved 
in 1 liter of water, the ratio of ascorbic acid developing agent to the 
auxiliary super-additive developing agent is at least about 10:1, and 
further provided that a borate buffer can be present as the sole buffer in 
either or both of the first and second packaged formulations in an amount 
sufficient to maintain a pH of from 7 and up to 9 when the first and 
second packaged formulations are mixed in water. 
Further, a method of processing to provide a black and white photographic 
image comprises: 
developing an imagewise exposed black and white silver halide photographic 
material with the aqueous black-and-white developing composition described 
above. 
The invention also provides a method of processing to provide a 
photographic image comprises: 
A) preparing a black-and-white developing composition that has a pH of from 
7 and up to 9, from the photographic developing kit described above, and 
B) developing an imagewise-exposed black-and-white silver halide 
photographic material with the black-and-white developing solution. 
The developing composition of this invention is free of hydroquinone and 
other dihydroxybenzene compounds. The composition can be readily 
formulated, shipped and stored as stable aqueous or readily soluble powder 
formulations because they have excellent long term stability. The powders 
readily dissolve in water at room temperature (that is, no heating is 
required). 
The compositions of this invention can be used in a variety of processors 
to develop various black-and-white films and papers and need no special 
replenisher. It has been observed that the properly replenished developer 
composition of this invention has less degradation by-products over time 
and can be used for a longer running time. It has also been unexpectedly 
found that the developing compositions provide up to one-third to one-half 
stop in real speed improvement over hydroquinone developing compositions. 
Granularity is also reduced, and most films show about 10% more 
enlargeability. 
Importantly, in aqueous formulations, the compositions are weakly alkaline, 
that is having a stable pH below 9, and thus avoid the problems of more 
highly alkaline developing compositions. 
All of these advantages are provided by formulating the composition to have 
a pH of at least 7 and up to, but less than 9, using a borate as the only 
buffer instead of the common carbonate or phosphate buffers or mixtures 
thereof. 
DETAILED DESCRIPTION OF THE INVENTION 
Ascorbic acid developing agents are described in a considerable number of 
publications in photographic processes, including U.S. Pat. No. 5,236,816 
(noted above) and references cited therein. Useful ascorbic acid 
developing agents include ascorbic acid and the analogues, isomers and 
derivatives thereof. They include, but are not limited to, D,L-ascorbic 
acid, sugar-type derivatives thereof (such as sorboascorbic acid, 
.gamma.-lactoascorbic acid, glucoascorbic acid, fucoascorbic acid, 
glucoheptoascorbic acid, maltoascorbic acid, L-arabosascorbic acid), 
sodium ascorbate, potassium ascorbate, isoascorbic acid (or 
L-erythroascorbic acid), and salts thereof (such as alkali metal, ammonium 
or others known in the art), endiol type ascorbic acid, an enaminol type 
ascorbic acid, a thioenol type ascorbic acid, and an enamin-thiol type 
ascorbic acid, as described for example in U.S. Pat. No. 5,498,511 
(Yamashita et al.), EP-A-0 585,792 (published Mar. 9, 1994), EP-A-0 573 
700 (published Dec. 15, 1993), EP-A-0 588 408 (published Mar. 23, 1994), 
WO 95/00881 (published Jan. 5, 1995), U.S. Pat. No. 5,089,819 and U.S. 
Pat. No. 5,278,035 (both of Knapp), U.S. Pat. No. 5,384,232 (Bishop et 
al.), U.S. Pat. No. 5,376,510 (Parker et al.), Japanese Kokai 7-56286 
(published Mar. 3, 1995), U.S. Pat. No. 2,688,549 (James et al.), U.S. 
Pat. No. 5,236,816 (noted above) and Research Disclosure, publication 
37152, March 1995. D- or L-, a mixture of D,L-ascorbic acid (and alkali 
metal salts thereof) or isoascorbic acid (or alkali metal salts thereof) 
are preferred. Sodium ascorbate and sodium isoascorbate are most 
preferred. Mixtures of these developing agents can be used if desired. 
The developing composition of this invention also includes one or more 
auxiliary super-additive developing agents, which are also well known 
(e.g., Mason, Photographic Processing Chemistry, Focal Press, London, 
1975). Super-additivity refers to a synergistic effect whereby the 
combined activity of a mixture of two developing agents is greater than 
the sum of the two activities when each agent is used alone in the same 
solution. 
Any auxiliary super-additive developing agent can be used, but the 
3-pyrazolidone developing agents are preferred (also known as "phenidone" 
type developing agents). Such compounds are described, for example, in 
U.S. Pat. No. 5,236,816 (noted above). The most commonly used compounds of 
this class are 1-phenyl-3-pyrazolidone, 
1-phenyl-4,4-dimethyl-3-pyrazolidone, 
4-methyl-4-hydroxymethyl-1-phenyl-3-pyrazolidone and 
1-phenyl-4,4-dihydroxymethyl-3-pyrazolidone. A most preferred compound is 
4-methyl-4-hydroxymethyl-1-phenyl-3-pyrazolidone. 
Less preferred auxiliary super-additive developing agents include 
aminophenols such as p-aminophenol, o-aminophenol, N-methylaminophenol, 
2,4-diaminophenol hydrochloride, N-(4-hydroxyphenyl)glycine, 
p-benzylaminophenol hydrochloride, 2,4-diamino-6-methylphenol, 
2,4-diaminoresorcinol and N-(beta-hydroxyethyl)-p-aminophenol. 
A mixture of different types of auxiliary super-additive developing agents 
can also be used if desired. 
Borate is used as the only buffer in this invention. It can be used in any 
suitable form, including boric acid, sodium metaborate, potassium 
metaborate, sodium tetraborate, potassium tetraborate and other forms 
readily apparent to one skilled in the art. Mixtures of such compounds can 
be used if desired. Borate is not required in the developer composition, 
but is preferably present at up to 0.2 mol/l and more preferably at from 
0.001 to 0.16 mol/l. 
The developing composition also includes one or more preservatives or 
antioxidants. Various conventional black-and-white preservatives can be 
used including sulfites. A "sulfite" preservative is used herein to mean 
any sulfur compound that is capable of forming or providing sulfite ions 
in aqueous alkaline solution. Examples include, but are not limited to, 
alkali metal sulfites, alkali metal bisulfites, alkali metal 
metabisulfites, amine sulfur dioxide complexes, sulfurous acid and 
carbonyl-bisulfite adducts. Mixtures of these materials can also be used. 
Examples of preferred sulfites include sodium sulfite, potassium sulfite, 
lithium sulfite, sodium bisulfite, potassium bisulfite, sodium 
metabisulfite, potassium metabisulfite and lithium metabisulfite. The 
carbonyl-bisulfite adducts that are useful include alkali metal or amine 
bisulfite adducts of aldehydes and bisulfite adducts of ketones. Examples 
of these compounds include sodium formaldehyde bisulfite, sodium 
acetaldehyde bisulfite, succinaldehyde bis-sodium bisulfite, sodium 
acetone bisulfite, beta-methyl glutaraldehyde bis-sodium bisulfite, sodium 
butanone bisulfite, and 2,4-pentandione bis-sodium bisulfite. 
The developing composition can contain other additives including various 
metal ion sequestering agents (such as complex phosphates, hydroxy acids 
and aminocarboxylic acids), antifoggants, non-super-additive developing 
agents, development restrainers, development accelerators, swelling 
control agents, stabilizing agents, and development boosters in 
conventional amounts. Examples of such optional components are described 
in U.S. Pat. No. 5,236,816, U.S. Pat. No. 5,474,879 (Fitterman et al.), 
Japanese Kokai 7-56286 and EP-A-0 585 792 (all noted above). Particularly 
useful sequestering agents include ethylenediaminetetraacetic acid, 
diethylenetriaminepentaacetic acid, 1,3-propylenediaminetetraacetic acid, 
1,3-diamino-2-propanoltetraacetic acid, ethylenediaminodisuccinic acid and 
ethylenediaminomonosuccinic acid. The sequestering agents can be present 
in an amount of from 0 to about 0.02 mol/l. 
The developing compositions are free of hydroquinone and other 
dihydroxybenzene compounds, meaning that they are either completely free 
of such compounds, or contain so little of such compounds that those 
compounds provide no silver halide developing activity. 
The pH of the developing composition of this invention is weakly alkaline, 
that is at least 7 and up to, but not including 9. Preferably, the pH is 
from 8 to 8.5, and more preferably, it is from 8.0 to 8.4. 
When formulated in an aqueous solution, the developing composition includes 
the essential components in the following amounts: 
the ascorbic acid developing agent at from about 0.01 to about 0.1 mol/l, 
and preferably from about 0.02 to about 0.07 mol/l, 
the auxiliary super-additive developing agent at from about 
2.5.times.10.sup.-4 to about 2.5.times.10.sup.-2 mol/l, and preferably 
from about 5.times.10.sup.-4 to about 2.times.10.sup.-3 mol/l, 
borate buffer in an amount of up to 0.2 mol/l, and preferably from about 
0.001 to about 0.16 mol/l, and 
preservative at from about 0.4 to about 1.6 mol/l, and preferably from 
about 0.4 to about 0.8 mol/l. 
The molar ratio of the ascorbic acid developing agent to the auxiliary 
super-additive developing agent is at least about 10:1, and preferably, it 
is from about 20:1 to about 50:1. 
As noted above, the developing composition can be formulated as an aqueous 
solution that can be used directly as the working solution or as the 
developer replenisher, or it can be in a concentrated solution that is 
suitably diluted. 
Alternatively, the composition can be prepared as a dry powder, pellets, 
granules or tablets using conventional procedures. 
Preferably, the present invention provides a black-and-white developing kit 
having at least two separately packaged formulations, at least one 
formulation being packaged in dry form. Each packaged formulation is free 
of dihydroxybenzene developing agents as described above 
The first packaged formulation comprises an ascorbic acid developing agent, 
and a first preservative, wherein the molar ratio of the first 
preservative to the developing agent is at least 4:1, and preferably from 
7:1 to 20:1. 
The second packaged formulation comprises the auxiliary super-additive 
developing agent and a second preservative, wherein the molar ratio of the 
second preservative to the auxiliary super-additive developing agent is at 
least 4:1, and preferably from 50:1 to 200:1. 
Moreover, when the first and second packaged formulations are dissolved in 
water for use in processing, the ratio of the ascorbic acid developing 
agent to the auxiliary super-additive developing agent is at least 10:1, 
and preferably from about 20:1 to about 50:1. 
The borate can be present in either or both packaged formulations (or 
neither, if separately added) in an amount sufficient to maintain a pH of 
from 7 and up to 9 when the two formulations are mixed in water. 
Preferably, the borate buffer is in the second packaged formulation. 
Preferably, the first and second preservatives are sulfite ions that can be 
supplied from the same or different compounds. At least one of the 
formulations also contains a sequestering agent or any other desired 
additive. 
At least one of the separately packaged formulations is in dry form, such 
as a fine powder or granules. Preferably, both separately packaged 
formulations are in dry form. The formulations can generally be dissolved 
in water in any suitable fashion. 
Preferably, the separately packaged formulation containing the auxiliary 
super-additive developing agent and optional borate buffer is dissolved in 
water first, followed by the separately packaged formulation containing 
the ascorbic acid developing agent. Generally, the first dissolved 
formulation is more alkaline (generally from 9.5 to 11) than the second 
dissolved formulation, but the final pH of both dissolved formulations is 
within the desired range. 
The developing compositions of this invention are useful for forming 
black-and-white silver images by development of light-sensitive silver 
halide photographic elements of various types including, but not limited 
to, microfilms, aerial films, black-and-white motion picture films, 
duplicating and copy films, and amateur and professional continuous tone 
black-and-white films. Preferably, the amateur and professional 
black-and-white films are processed using this invention. The processed 
materials can have any suitable silver halide emulsion known for this 
purpose, the details of which are described in Research Disclosure, 
publication 36544, pages 501-541 (September 1994), and U.S. Pat. No. 
5,384,232 (noted above). Research Disclosure is a publication of Kenneth 
Mason Publications Ltd., Dudley House, 12 North Street, Emsworth, 
Hampshire PO10 7DQ England (also available from Emsworth Design Inc., 121 
West 19th Street, New York, N.Y. 10011). Preferred emulsions useful in the 
invention include silver bromide and silver bromoiodide emulsions (having 
up to 15 mol % iodide, based on total silver). 
In processing the photographic elements, the time and temperature for 
development can be varied widely. Typically, the temperature will be in 
the range of from about 18 to about 40.degree. C., and the time will range 
from about 180 seconds to about 20 minutes. More preferably, the 
temperature can be in the range of from about 20 to about 25.degree. C., 
and the time at from about 3 to about 10 minutes. 
The developing composition of this invention can be used as its own 
replenishing solution. 
Following development, the photographic materials can then be processed 
with one or more additional steps that are known in the art using 
conventional processing solutions. Such additional steps include 
development stop, fixing, washing and drying. The Research Disclosure 
publication, noted above, describes the components of such processing 
solutions. Typical fixing solutions include a fixing agent, such as a 
thiosulfate or thioether, and one or more low pH buffers, and sequestering 
agents. Suitable fixing times and temperatures can be used. 
After fixing, the photographic elements are generally washed to remove 
silver salt dissolved by fixing, at suitable times and temperatures. 
Processing according to the present invention can be carried out using 
conventional tanks, trays and automated processing machines holding 
processing solutions. Alternatively, it can be carried out using what is 
known in the art as "low volume thin tank" processing systems using either 
rack and tank or automatic tray designs. Such processing methods and 
equipment are described, for example, in U.S. Pat. No. 5,436,118 (Carli et 
al.) and publications cited therein.

The following examples are provided to illustrate the practice of this 
invention, and are not meant to be limiting in any manner. All percentages 
are by weight unless otherwise indicated. 
EXAMPLE 1 
Preferred Developing Kit 
The following developing kit having two dry powder formulations was 
prepared and used to prepare an aqueous black-and-white developing 
composition, as follows: 
Part A (Dry Formulation): 
Sodium sulfite 10 g 
Diethylenetriaminepenta-acetic acid, pentasodium salt 1 g 
Sodium metaborate (8 mol) 4.0 g 
4-Hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone 0.2 g 
Part B (Dry Formulation): 
Sodium sulfite 75 g 
Sodium metabisulfite 3.5 g 
Sodium isoascorbate 12 g 
Part A was dissolved completely in 850 ml of water at room temperature, 
having a pH of 10.19 .+-.0.05. Part B was then dissolved in the solution 
at room temperature, and water was added to 1 liter. The final pH was 
8.20.+-.0.05. 
EXAMPLES 2-5 
Aqueous Developing Compositions 
The following components were formulated into liquid developer compositions 
of this invention: 
______________________________________ 
Example 2 
Example 3 
Example 4 
Example 5 
______________________________________ 
Water 800 g 800 g 800 g 800 g 
Sodium hydroxide (50%) 
12.35 g 16.5 g 0 0 
Diethanolamine (with 
75 g 100.0 g 15.3g 23 g 
16% sulfur dioxide) 
4-Hydroxymethyl-4- 
0.55 g 0.73 g 0.67 g 1.0 g 
methyl-1-phenyl-3- 
pyrazolidone 
Diethylenetriaminepenta- 
2.5 g 3.3 g 1.67 g 2.5 g 
acetic acid, pentasodium 
salt (40%) 
Sodium metabisulfate 
18.8 g 25.1 g 0 0 
Ascorbic acid 
8.0 g 10.7 g 10.0 g 15.0 g 
Sodium sulfite 
0 0 36.0 g 54.0 g 
Sodium bicarbonate 
0 0 13.3 g 20.0 g 
Water was added to 1 
liter; pH = 8.0 
______________________________________ 
EXAMPLE 6 
Processing of Black-and-White Films 
Several commercially available black-and-white camera speed films were 
processed according to the present invention using the following 
processing protocol: 
______________________________________ 
Development 20 .degree.C. 
Various times 
Stop bath 20 .degree.C. 
30 seconds 
Fixing 20 .degree.C. 
3-10 minutes 
Washing 20 .degree.C. 
5-20 minutes 
Drying 
______________________________________ 
A rectangular stainless steel tank, outfitted with a nitrogen sparger for 
agitation, was used with 8 liters of solution for film processing. During 
development, nitrogen burst agitation was used one second for every 
fifteen seconds. The same tanks were used for the stop bath, fixing and 
washing. The stop bath and fixing solution had the same agitation as the 
developer solution, but the washing solution was continuously agitated 
with nitrogen bursts. 
Film samples were exposed with a 1-B sensitometer with 55K color 
temperature and 21-step carbon tablet with a density range of from 0-4 in 
equal 0.2 increments. The time of development series ranged from 3 to 15 
minutes. The samples were evaluated on a visual channel of a densitometer, 
and the data in the following Table I were interpolated from points thusly 
generated. 
Development was carried out using the developer composition described in 
Example 1 or commercially available "Control" developers described below. 
The films were fixed using conventional KODAK RAPID FIXER.TM., and washed 
with water. 
The two "Control" developers were KODAK D-76.TM.Developer and KODAK 
T-MAX.TM. Developer both containing hydroquinone. 
The various black and white films processed in this manner were 
commercially available from Eastman Kodak Company. 
The results of processing the various films are shown in Table I below. The 
data show that, in comparison to standard hydroquinone-containing 
developers, such as KODAK D-76.TM. or KODAK T-MAX.TM., developers of this 
type can duplicate results without having to rely upon hydroquinone. Films 
processed in these developers show enhanced speed, image quality, and tone 
reproduction at a desired process rate. 
TABLE I 
__________________________________________________________________________ 
Log E 
at Time to 
Time to 
ANSI* 
Exposure 
CI 0.56 
CI 0.82 
Dmin at 
Dmin at 
Film Developer 
0.62 
Index 
(Normal) 
(+3 Stops) 
CI 0.56 
CI 0.82 
__________________________________________________________________________ 
KODAK Example 1 
-2.18 
125 6.6 10.5 0.20 
0.23 
TMAX Example 2 
-2.23 
125 6.4 16.0 0.22 
0.26 
100 .TM. 
Example 3 
-2.22 
125 5.6 11.0 0.22 
0.25 
Example 4 
-2.14 
100 4.3 8.6 -- -- 
Example 5 
-2.20 
125 4.1 7.5 -- -- 
D-76 -2.10 
100 6.7 10.2 0.22 
0.27 
T-MAX 
-2.26 
160 6.7 11.6 0.23 
0.27 
KODAK Example 1 
-2.75 
400 6.3 9.5 0.23 
0.26 
TMAX Example 2 
-2.84 
500 7.5 12.0 0.24 
0.27 
400 .TM. 
Example 3 
-2.84 
500 6.4 10.0 0.24 
0.26 
Example 4 
-2.90 
640 5.1 8.0 -- -- 
D-76 -2.76 
500 7.6 11.0 0.24 
0.25 
T-MAX 
-2.79 
500 6.0 9.5 0.26 
0.30 
KODAK Example 1 
-3.00 
800 8.0 12.0 0.27 
0.31 
TMAX Example 2 
-3.15 
1250 9.0 14.0 0.35 
0.39 
P3200 .TM. 
Example 3 
-3.16 
1250 8.0 12.0 0.33 
0.38 
D-76 -3.00 
800 9.6 14.0 0.33 
0.38 
T-MAX 
-3.05 
1000 7.4 11.3 0.34 
0.40 
KODAK Example 1 
-2.80 
500 7.0 11.0 0.27 
0.29 
TRI-X- 
Example 2 
-2.80 
500 7.5 16.0 0.28 
0.30 
PAN .TM. 
Example 3 
-2.80 
500 6.6 13.5 0.29 
0.31 
Example 4 
-2.83 
500 5.4 10.5 -- -- 
D-76 -2.65 
400 6.5 12.0 0.26 
0.28 
T-MAX 
-2.77 
500 6.7 12.0 0.32 
0.36 
KODAK Example 1 
-2.37 
200 6.5 12.0 0.33 
0.35 
PLUS- Example 2 
-2.28 
160 12.0 -- 0.32 
-- 
X-PAN .TM. 
Example 3 
-2.33 
160 8.4 -- 0.32 
-- 
D-76 -2.20 
125 5.6 12.0 0.30 
0.32 
T-MAX 
-2.34 
160 6.2 -- 0.42 
-- 
__________________________________________________________________________ 
*Log E at ANSI 0.62 was calculated according to the standard ISO method. 
Exposure Index (EI) was determined from this using the ISO method and 
tables See American National Standards Institute, ISO 6, Publication No. 
1993(E)!. 
"CI" refers to Contrast Index as defined in "KODAK Professional Black and 
White Films", Kodak Publication F5, Eastman Kodak Company, 1990, pages 
14-24. 
The invention has been described in detail with particular reference to 
preferred embodiments thereof, but it will be understood that variations 
and modifications can be effected within the spirit and scope of the 
invention.