US2879160A - Composition for developing surface disturbances on a photographic film - Google Patents

Description

COMPOSITION FOR DEVELOPING SURFACE DIS- .TURBANCES ON A PHOTOGRAPHIC FILM Isaac Moyer Hunsherger, Yellow Springs, Ohio, assignor to Antioch College of Yellow Springs, Greene County, Ohio, a corporation of Ohio No Drawing. Application September 9, 1954 Serial No. 455,073

4 Claims. (CI. 96-66) This invention relates to amethod of developing surface disturbances on unexposedphotographic film. More particularly it relates to a method of producing fingerprints on unexposed photographic film and to a novel chemical compound which, when added to certain photographic developers, produces this result.

A great amount of work has been done ,in recentyears in connection with photographic developers in an effort to find substances which, when added to the photographic developer, enhance the effective film speed so that acceptable negatives may be obtained from underexposed .film. Thus, it is known to add hydrazine dihydrochloride to a high alkali metol hydroquinone developer for the purpose of increasing the effective film speed. (Metol is a trade name for methyl-para-aminophenol sulfate.)

In connection with research along these lines, I have discovered that a particular hydrazine compound produces certain novel and completely unexpected results, in thatsurface disturbances on the emulsion surface, produced by pressure or the like, are developed on the film and that these results are obtained with additions of minute quantities of the particular compound in question to the appropriate photographic developer.

It is therefore an object of the present invention to provide as an article of manufacture a compound which may be added to a photographic developer for developing rates Patent sults have been obtained with Eastman FD-81 D-42 Water to make 1 liter.

(Elon is a trade name for methyl-para-aminophenol sulfate.)

The particular hydrazine compound which produces the results above outlined is p-sec-amylphenylhydrazine (otherwise designated as p-(1-methylbuty1)phenylhydrazine). The hydrochloride ofthis compound is added to the high alkali metol hydroquinone developer in the very small concentration of 1" .l0- moles per liter, which amounts to only 2.1 mgs. per liter of developer. When the D-19 developerisnsed without the hydrazine compound, no fingerprintis developedbut With the small concentration of the hydrazine compound added, clear and legible fingerprints are obtained.

The fingerprint or other surface disturbance is accomplished on the emulsion surface of the film in total darkness and the film is developed without exposure to light.

surface disturbances on an unexposed photographic film. t

Excellent results have been obtained by development for eight minutes in a tank with mechanical agitation using D-l9 developer containing 2.1 mgs. per liter of p-secamylphenylhydrazine hydrochloride. 'The development time depends upon the 'type of film and the developer used. The film must'be fogged by development, and'optimum fog appears to 'be between 0.70 and 1.6.

I have noted that fingerprints develop more legibly if the hands .have not been'freshly washedand dried. Similarly, a rubber stamp impression on a photographic emulsion will develop more legibly and clearly, if the rubber stamp has been surface coated with any of such substances as pure butyric acid, butyric acid in dilute aqueous solutions, distilled water, tap water, pelargonic acid, hydrochloric acid, ethyl alcohol, etc. Since butyric acid is present in perspiration, this may be why clean dry fingers do not produce as good a print as fingers which are not freshly washed and dry.

I have made similar tests using rubber stamps coated V with a film of the various compounds mentioned above speed panchromaticfilm and press .the finger against the emulsion side of the film in total darkness. I then develop the film in a metol hydroquinone developer .to which I have added a minute quantity of the hydrazine compound, which will be described hereinafter. Upon development very legible fingerprints are obtained and contact prints made from such negatives show fingerprints of high quality.

With the particular compound to be described herein after, successful results can be obtained with any of the high speed panchromatic photographic films. In my experience I have been able to develop fingerprints on films known commercially as Ansco Triple S Pan Sheet Film," Eastman Kodak Aerographic Tri-X, Super-XX, Plus- X and Verichrome films; however the best results have been obtained with Ansco Triple S Pan Sheet Film and Eastman Kodak Aerographic Tri-X. Similarly, I have obtained best results with a high alkali metol hydroquinone developer manufactured by Eastman Kodak, Inc. under the name of D-19, although reasonably good rewith development in D49 containing no p-sec-amylphenylhydrazine. I found that if the developing temperature was raised from 68 F. to 80 F. and if the -development time was increased 'fromabout 8 minutes to about 20 minutes so as to attain the desired high fog level, clear images of the stamp were obtained on development. Interestingly, however, the stamped area on the negative was darker, i. c. more silver grains, so that in the contact prints the stamped areas were lighter than the surrounding area. When p-sec-amylphenylhydrazine was added to the developer, exactly the reverse effect was produced. In other Words, the stamped area of the negative was lighter and on the contact print the stamped area was darker.

While I do not wish to be bound by my theory, I believe that one of the functions of the coating, either on the rubber stamp or on the finger, is to retard in some way the development rate of that area of the film which I was disturbed by the stamp. The reversal effect with dred hydrazine compounds which I have tested over a three-year period, p-sec-amylphenylhydrazine is the only one which produces legible fingerprints although some of the other compounds do, to some extent, produce develop ment of abrasions and scratches to varying degrees. The structurallyvery closely related t-butylphenylhydrazines atjfaconcentration of 1 10- M in D-l9 displayed some activity in developing impressions made by rubber stamps coated with a variety of the substances mentioned above. However, the t-butylphenylhydrazines showed no'activity'whatever in developing fingerprints on negatives even "though theorthoInieta, andypara isomers were tested. at concentrations of l 10- and 1X 10 M in .*D-19.-'- 1 a T he particularhydrazine derivative here involved has beenv unreported in the literature up to the present time. Itmay be preparedby diazotization of p-sec-amylaniline followed byreduction of the diazonium salt with stannous chloride and hydrochloricacid' Thus, 22.5 g. offreshly distilled (from zinc dust) p'- sec-'amylanilineis' mixed with 51 ml. of concentrated hydrochloric acid and diazotized at below zero degrees C.

with 9.5 g. of sodium nitrite 45 ml. of water. On stirring the-mixture for an additional half hour, its surface becomes dark red.

Reduction is. accomplished at below zero degrees C. by adding '90 g. of stannous chloride dihydrate in 94 ml. of concentrated hydrochloric acid. The original light tan slurry gradually assumes the consistency of thick dough.

After overnight refrigeration, the slurry is filtered as completely as possible and the collected semi-solid material is-treated with an excess of sodium hydroxide, The now bright yellow product is extracted into ether and the dried and cooled extract is treated with dry hydro.- gen chloride. Since'the impure hydrochloride separates,

partly as a yellow solid and partly as a cherry red viscous liquid, it is converted back to the free base and the latter is distilled at 2 mm. of mercury'from a pear-shaped flask attached to a small fractionatin'g column. After considerable low boiling forerun, 9.4 g. (which is 38% of the theoretical yield) of; the viscous yellow hydrazine di soniorncrnon NHNHaHGl Two 4 The molecular formula of the compound is C I-1 N 01. The calculated neutral equivalent is 214.8 and the neutral equivalent as found is 215. The calculated percentage of nitrogen was 13.05 and the percentage of nitrogen found was 13.09. One gram of this hydrochloride salt is sufiicient for preparing over 400 liters of the modified high alkali metol hydroquinone developer.

Since the fingerprints are developed on the film without exposing the film to light before development, it appears that. the addition of p-sec-amylphenylhydrazine hydrochloride to a high alkali metol hydroquinone developer reveals at latent sensitivity in the film, but I am unable to explain 'the'reasons for this result. It is apparently not related to the ability of the hydrazine to increase emulsion speed, for other hydrazines which are equally potent in increasing film speed fail to show the fingerprint activity.

While there may be many applications where it is desired to render a photographic fihn sensitive as described above, one very useful purpose, as has been pointed out above, is for the production of fingerprints. The method outlined herein is simpler and more pleasant than the ink method currently being used. The ridges of the finger form the dark lines on the contact print, so that a print taken according to the present invention, matches exactly with one taken'by the conventional ink method. Furthermore, the prints of a large number of people may be obtained in a very short time and the film strips may then be developed immediately or transported to a laboratory for development. Also, large numbers of prints can be permanently stored on a single film strip.

Having now fully described my invention, what I'claim as new and-desire to secure by Letters Patent is: 1'. A photographic developer containing monomethyh para-aminophenol-sulfate, hydroquinone and a minute quantity of p-sec-amylphenyIhydraZine hydrochloride."

2. A photographic developer containing monomethylpara-aminophenol-sulfate, hydroquinone, and p-sec-amyl phenylhydrazine hydrochloride in a concentration of about 2 mg. per liter.

3. A high alkali photographic developer containing monomethyl-para-aminophenol-sulfate, hydroquinone and a minute quantity of p-sec-amylphenylhydrazine hydrochloride.

4. A high alkali photographic developer containing monomethyl para aminophenol-sulfate, hydroquinone and p-sec-amylphenylhydrazine hydrochloride in a concentration of about 2 mg. per liter.

" References Cited in the file of this patent UNITED STATES PATENTS

Claims (1)

1. A PHOTOGRAPHIC DEVELOPER CONTAINING MONOMETHYLPARA-AMINOPHENOL-SULFATE, HYDROQUINONE AND A MINUTE QUANTITY OF P-SEC-AMYLPHENYLHYDRAZINE HYDROCHLORIDE.