US3674490A - Process for the production of photographic images - Google Patents

Abstract

PHOTOGRAPHIC IMAGES ARE PRODUCED BY IMAGEWISE PRODUCTION OF NUCLEI FOR THE DECOMPOSTITION OF PEROXY COMPOUNDS IN THE PRESENCE OF REACTION COMPONENTS FOR A COLORFORMING OXIDIZING REACTION. THE IMAGE DYE CONSISTS AT LEAST IN PART OF THE DYE OBTAINED BY THE OXIDIZING REACTION.

Description

United States Patent 3,674,490 PROCESS FOR THE PRODUCTION OF PHOTOGRAPHIC IMAGES Reinhart Matejec, Leverkusen, Germany, assignor to Agfa-Gevaert Aktiengesellschaft, Leverkusen, Germany No Drawing. filed Dec. 2, 1969, Ser. No. 881,610 Claims priority, application Germany, Dec. 11, 1968, P 18 13 920.3 Int. Cl. G03c 5/24, 7/00, 1/00 US. Cl. 96-48 R 14 Claims The invention relates to a new process for the production of photographic images by catalytic decomposition of peroxy compounds of imagewise distributed noble metal nuclei.

A Wide variety of processes is known for the production of photographic images. The conventional photo graphic processes in which silver halide emulsion layers are exposed and developed with conventional developer substances have for a long time been of greatest practical importance but they have their limitations regarding sensitivity and sharpness of the image so that there have been many attempts to develop new processes which make use of both physical and chemical principles.

It is among the objects of the invention to provide processes for the production or intensification of monochrome or multicolored photographic images in a simple and economical manner.

I now have found a process for the production of photographic images including the following steps:

1) Imagewise exposure of light-sensitive layers to produce nuclei for the decomposition of peroxy compounds in imagewise distribution, the nuclei being of noble metals of the Groups Ib and VIII of the Periodic Table of Elements.

(2) Treatrnent with peroxy compounds which are catalytically decomposable at these nuclei in the presence of reagents for a color-forming oxidation reaction.

Photochemical decomposition of noble metal compounds to form the free metals has been known for a long time. Thus, gold compounds are photochemically decomposed to form gold nuclei. The same applies to noble metal compounds of the eighth group of the periodic system. The noble metal compounds are preferably salts of the noble metals with organic acids such as citric acid, tartaric acid, oxalic acid, salicylic acid, lactic acid, benzoic acid, mucic acid, etc., as well as halides, cyanides, thiocyanates and the like. See, for example, the relevant chapter in the work by J. Plotnikow Allegemeiue Photochemie, publishers W. de Gruyter & Co., Berlin- Leipzig, (1936), and the work by A. Hay Handbuch der Wissenschaftlichen und Angewandten Photographic, publishers Springer-Verlag, Vienna (1929), volume 3. For the process according to the invention, compounds of this type may be incorporated in layers in concentrations of to 10 g./m. preferably 10- to 10 g./m. Upon the photochemical decomposition nuclei are formed on which the color-forming reactions described below can be carried out.

3,674,490 Patented July 4, 1972 'ice In the light-sensitive layers of the type described above the noble metal compounds are themselves sufficiently sensitive to light so that catalytically active noble metal nuclei are formed in sufficient quantities in the exposed areas. However, one can also use for the process according to the invention layers in which other substances undergo an imagewise change on exposure so that the noble metal compounds which are present at the same time in the layer or which are added subsequently are converted in the exposed areas into noble metal nuclei which are then capable of catalytically decomposing peroxides. Layers of this type are known per so. They are layers which contain photo-conductive compounds such as zinc oxide, titanium dioxide, bismuth oxide, tin dioxide, lead oxide, halides, sulfides or selenides of these metals and others. In this connection, I refer to the publication by A. Goetz et al. in Rev. Mod. Physics 20 (1948) 131 and the publication by G. M. Schwab et al. in Photographic Science, Focal Press London/New York (1963), page 343 or British Pat. No. 1,043,250.

Layers which are particularly suitable are those which contain zinc oxide or titanium dioxide embedded in any binders but in particular in hydrophilic binders, such as silica gel, polyvinyl acetate, partially hydrolysed polyvinyl acetate, polyvinyl alcohol, cellulose esters, carbonymethyl cellulose or natural binders such as gelatin.

The noble metal compounds are added to these layers before or after exposure. The noble metal compounds need not themselves to be light-sensitive. The noble metal compounds are reduced in the exposed areas of the layers so that noble metal nuclei which are capable of catalytically decomposing peroxy compounds are formed in imagewise distribution.

The process of the invention exhibits particular utility for intensifying conventional photographic silver images which have been produced with conventional silver halide emulsion layers and in particular images in layers of this type which have a low silver content. For this purpose the imagewise exposed silver salt emulsion layer is first developed in a conventional way. The silver image thus formed is capable of the catalytically decomposing the peroxy compound.

If desired, the catalytic activity of the surface of the developed silver image may be still further increased by taking suitable measures after development and before treatment with the peroxy compound. Such increases in the catalytic activity of the developed silver image may be achieved, for example, by depositing traces of catalytically more active noble metals (e.g. Au, Pt, Pd, Ru, Os) on the surface of the image silver or by brief oxidative pretreatment of the image silver, for example with peroxy compounds preferably inorganic peroxy compounds, e.g. with dissolved or gaseous H 0 dissolved perborate, percarbonate or the like.

A certain increase in the catalytic activity of the developed image silver also occurs if additional silver ions are deposited on the surface of the silver image from the solution phase by brief physical after-development. The silver surface is then purified by displacement of adsorbed, inactivating substances (e.g. emulsion stabilizers), and its catalytic activity is increased.

Due to the high catalytic activity of silver, silver oxide or noble metal nuclei on the decomposition of peroxide, even invisible traces of the noble metal in particular of silver initiate the color-forming oxidation reaction. In other words, parts of the image become visible which would remain invisible if processed only according to conventional photographic processing of exposed silver halide emulsion layers. The relative gain in sensitivity lies between 5 and 10 DIN.

For instance a low sensitivity fine grained silver halide emulsion layer which upon conventional processing has a sensitivity of about 13 DIN can be exposed as an emulsion with a sensitivity of 20 D'IN if processed according to the present invention, without any loss of details or density in the resulting image.

The gain in photographic sensitivity by the process of the invention is particularly high if silver salt emulsion layers with the conventional higher silver content are used.

But images of high density and contrast can be obtained also using light-sensitive silver salt emulsion layers especially silver halide gelatin emulsion layers which have a silver content of only about 0.05-0.3 gram silver per square meter in the form of light-sensitive silver salt. Apart from the considerable economic advantage this leads to images of exceptionally high sharpness because light scattering in layers having a low silver halide content is reduced as compared with conventional silver halide layers, which have a much higher silver halide content.

In general, the fixing or bleach fixing process can be omitted for layers which have an extremely low silver halide content since the photolytic coloration in daylight of layers which have an exceptionally low silver content is much less than that of conventional layers which have a much higher silver content.

The process of the invention can be performed with silver salt emulsion layers of common composition, for example silver halide, gelatin emulsion layers, which however may contain as already mentioned above for less silver salts. The silver salt emulsion layers used for the process of the present invention may contain the usual additives such as spectral or chemical sensitizers, accelerators, stabilizers, hardening agents, wetting agents, and so on.

The process according to the invention may be used both for intensifying black-white silver images and for intensifying color photographic images.

Peroxy compounds which are suitable for the process according to the invention are preferably inorganic peroxy compounds, e.g. hydrogen peroxide, perborates, percarbonates or persulfates, the last mentioned peroxy compounds preferably in the form of their alkali metal salts. Organic peroxy compounds, e.g. benzoyl peroxide, may also be used.

The treatment with the peroxy compounds is perrformed in the presence of reagents which yield very deeply colored oxidation products so that the image which was previously invisible or hardly visible becomes clearly visible.

These reagents may be organic compounds which yield an image dye on oxidation, preferably (1) amino and/or hydroxy substituted aryl compounds, in particular those of the benzene or naphthalene series or (2) amino and/or hydroxy substituted heterocyclic aromatic compounds, such as 5- or 6-membered heterocyclic rings, in particular rings with nitrogen as a ring member, for example rings of the pyrol, pyridine, pyrazole, imidazole, triazole, pyridazine, pyrimidine or pyrazine series, whereby these heterocyclic rings contain anellated benzene rings, such as indol, indazole, quinazoline, quinoxazaline, acridine or phenazine. The compounds are preferably water soluble.

The following are given as examples: Phenol, aniline, pyrocatechol, resorcinol, hydroquinone, 0-, mand p-phenylenediamines, N,N dimethyl phenylenediamine, N,N-diethyl-phenylenediamine, CN,-N-ethylmethyl-phenylenediamine, o-, mand p-aminophenols, p-methylaminophenol, 2,4-diaminophenol-(1), 1,7-, 1,5- or 2,3-dihydroxy-naphthalene, 1,6,7-trihydroxynaphthalene, 1,2-diamino-naphthalene, 1,8-diaminonaphthalene, benzidine, 2,2'-dihydroxybenzidine, 2,4-diamino diphenylamine; 3,8- dihydroxy quinoline, S-hydroxyquinoline, 2-hydroxycarbazol, l-phenylpyrazolone-( 3 etc.

The amino, hydroxy or aminohydroxy compounds may also be substituted, e.g. with halogen, sulfonic, alkyl, aryl, alkoxy or aroxy nitro, keto, aldehyde groups, carboxy or carbamoyl. The following are given as examples: 2,5- dichloro-p-phenylenediamine, l-hydroxy-2-aminobenzine- 4-sulfonic acid, -1 amino 2 hydroxybenzene-4-sulfonic acid, 3-amino 5 sulfosalicyclic acid, 1,6,7-trihydroxynaphthalene-3-sulfonic acid, 1,8 dihydroxynaphthalenedisulfonic acid-(3,=6)-benzidine-2,2'-disulfonic acid, benzidine-3,3'-disulfonic acid, 4-methylphenol, Z-phenylphenylenediamine-( lA), 2-methoxyphenol, 2-amino-4-phenoxyphenyl-(l), 4-nitro-pryrocatechol, 2,4-diaminobenzaldehyde, l-carboxy-pyrocatechol-(3,4). More substituted compounds are listed in Example 6.

In some cases, mixtures of several such compounds show a much stronger dye formation on oxidation than the individual components. Thus, for example, a mixture of o-phenylenediamine and pyrocatechol results in increased dye formation. A mixture of N,N-diethyl-phenylenediamine and pyrocatechol yields a deeper and more neutral black dye than the individual compounds. Even components which do not form a dye upon oxidation on their own, such as tetrabromohydroquinone or tetrabromopyrocatechol, may enhance dye formation when added to other hydroxy, amino or aminohydroxy compounds.

Oxidation of the aromatic amino, hydroxy and/ or aminohydroxy compounds yields monomeric or polymeric dyes which are related to quinonimines and azines. Some examples of this oxidative dye formation are described in H. R. Schweizers work Kiinstliche Organische Farbstoffe und ihre Zwischenprodukte, publishers Springer-Verlag, Berlin, Gtittingen, Heidelberg (1964), pages 222, 275, 281 and 293; N. I. Woroshow Grundlagen der Synthese von Zwischenprodulrten und Farbstotfen, publishers Akademie-Verlag, Berlin (1966), pages 703 to 789', A. Schaeffer Chemie der Parbstotfe und deren Anwendung (Technische Fortschrittsberichte, volume 60), publishers Theodor Steinlropfi-Verlag, Dresden-Leipzig (1963), pages 59 et seq.

Apart from dye precursors, one may, of course, also use leuco dye compounds and vat dyes which can be oxidized to dyes. For examples, of these see H. R. SchWeizer Kiinstliche Organische Farbstofle und Zwischenprodukte, Springer-Verlag, Berlin-Giittingen, Heidelberg (1964), pp. 250 and 320.

Oxidisable organic compounds of the type which yield the image dye only in a sequence of reactions with other compounds are also suitable for use in the process of the invention. In principle, any reaction system which yields dyes on oxidative coupling may be used. Special reference may be made here to the so-called color-forming photographic developers of the phenylenediamine or aminopyrazolone series (see, e.g. C. E. K. Mees and T. H. James, The Theory of the Photographic Process," 3rd edition, MacMillan Co., New York (1966), page 382; H. R. Schweizer, Kiinstliche Organische Farbstofie und ihre Zwischenprodukte, Springer-Verlag, Berlin-Gottingen-Heidelberg (1964), page 295). Isocyclic and heterocyclic hydrazines can also be coupled oxidatively with suitable components to yield dyes ,(see e.g. H. Hiinig et al., Angew. Chem. 70 (1958) 215; S. Hiinig, Chimia 15 (1961) 133 and Angew. Chem. 74 (1962) 818). The color-forming photographic developed substances are catalytically oxidized on the imagewise distributed noble metal nuclei or noble metal particles by the peroxy compounds. Their oxidation products may then react with known photographic color couplers which are also present to form dyes. Any color couplers are suitable for this purpose, for example those of the phenol or naphthol series as cyan couplers, those of the pyrazolone indazol series as magenta couplers and those of the benzoyl-acetanilide series as yellow couplers.

EXAMPLE 1 A gelatin layer (thickness of layer 25 m.) on a cellulose trlacetate support is treated with a saturated aqueous solution Of Na [Pd (C204) 2] 5 After drying and imagewise exposure with ultraviolet light, the layer is treated for two minutes at 20 C. in the following developer bath:

Solution 1: 5 cc. of glacial acetic acid are added to 500 cc. of water. 3 g. of S-aminobenzidene hydrochloride and 2 g. of pyrocatechol are then dissolved in this solution. Solution 2: 10 g. of sodium acetate are dissolved in 500 cc. of water. 25 cc. of 30% aqueous H are then added.

The two solutions are mixed before use.

Nuclei of palladium metal are formed on the exposed areas of the layer during exposure. On development, these nuclei catalytically decompose the hydrogen peroxide present in solution 2 and the amine and phenol of solution 1 are imagewise oxidized to yield a brownish-black negative image of the original. The image dye is fast to diffusion.

After development, the layer is washed and dried.

EXAMPLE 2 A transparent support of cellulose triacetate is coated with a solution which contains 6 ml. of a 10% aqueous solution of polyvinyl alcohol and 2 g. of TiO of particle size 0.3 to 0.4 m. and 0.1 mg. of erythrosin as spectral sensitizer in 400 cc. of water. The layer is then dried.

Processing The dry layer is exposed in a sensitometer customarily used in the art behind a grey step wedge and then treated for 10 minutes with a aqueous solution of NaAuCl It is then washed and treated for 2 minutes in a bath of the following solutions at 20 C.

The three solutions are mixed before use.

The developed material is washed for half a minute and dried. A blue-violet negative image of the original is obtained.

Similarly satisfactory results are obtained by treating the exposed layer with a 5% aqueous solution of silver nitrate instead of a solution of Na(AuCl EXAMPLE 3 A silver iodobromide gelatin emulsion layer (4.5 mols percent of Agl) which must be as free as possible from fog, is applied onto a support of polyethylene terephthalate. Conventional silver content of about g. silver per square meter. Layer thickness approximately 10 After imagewise exposure (0.5 second with X-rays between fluorescent intensifying foils), the layer is treated for 5 minutes in the following developer at 20 C.:

G. p-Methylaminophenol 3.5 Hydroquinone 9.0 Na SO anhydrous 60.0 Na CO 40.0 KBr 1.0 In 1 liter of H 0.

After a brief washing, the layer is then fixed for 5 minutes in a bath of the following composition:

G. Na S O -5I-I O 250.0 NaHSO 20.0 In 1 liter of H 0.

After another brief washing, the layer is treated for 5 minutes in a solution which contains 25 g. of sodium percarbonate and 200 cc. of 30% aqueous H 0 in 1 liter of H 0. The catalytic activity of the surface of the developed silver is thus increased.

The layer is then treated for 2 minutes in the following bath:

Solution 1: 10 g. of pyrocatechol in 200 ml. water.

Solution 2. 10 g. of 1,7-dihydroxy naphthalene in 800 ml. water and added thereto 20 g. of sodium carbonate and 20 ml. of a S-N-sodium-hydroxide solution.

Solultion 3: 14 g. sodium perborate in 1 liter of water.

Solutions 1, 2 and 3 are mixed before use and the pH- value is adjusted to 12.

The layer is finally rinsed and dried. The treatment with the last-mentioned bath may be performed in daylight. The contrast of the original silver image is greatly enhanced by the after treatment. The sensitivity of the material is apparently also strongly increased since one either obtains much more image detail for the same exposure followed by conventional photographic processing or the exposure time required to obtain the same quality of final image is much less (factor 10 to 100) than would be required if exposure were followed by conventional photographic processing.

Instead of the intermediate treatment with sodium percarbonate which increases the catalytic activity of developed silver, the intermediate treatment may be carried out e.g. with a 2% aqueous sodium perborate solution, a 1% aqueous PdCl solution, a 1% aqueous PtCl solution or a 1% aqueous AuCl solution. A brief treatment with gaseous H 0 at a temperature of about C. (especially in the form of a mixture with gaseous NH also increases the catalytic activity of the image silver.

EXAMPLE 4 10 ml. of a silver bromide gelatin emulsion which is as free as possible from fog are added to 250 cc. of a 5% gelatin solution. 50 ml. of a 10% aqueous solution of the cyan color coupler:

SOQH

are stirred into this solution. The mixture is applied to form a layer of about 20' m. in thickness. Silver content unusually low, approximately 0.08 g./m.

After drying, the layer is exposed in a sensitometer for 1 second behind a grey step wedge and then treated with a color-forming developer for 2 minutes in the conventional manner in the following bath:

G. N,N-diethyl-p-phenylenediamino sulfate 2.8 Na SO anhydrous 2.0 Ethylenediamino tetraacetic acid sodium 2.0 IQBr 2.0 Hydroxylamine sulfate 1.2 K 'CO 75.0

To 1 liter of H 0.

A very weak, negative cyan dye image which contains image silver is obtained.

The layer is then treated for 5 minutes in a solution which contains 20 g. of sodium perborate and cc. of 30% H 0 to 1 liter of H 0. The catalytic activity of the silver image surface is thereby increased.

The layer is then treated for 5 minutes in the following bath:

Solution 1: 15 g. of phenylhydrazine-2-sulfonic acid sodium are dissolved in 500 cc. of 0.1% aqueous acetic acid.

Solution 2: 7 g. of sodium perborate and 40 g. of sodium acetate are dissolved in 500 cc. of water. 50 cc. of 30% of H are then added.

8 per square meter 0.1 g. of silver in the form of silver halide.

The above layer is arranged between two intensifying foils of calcium tungstate and exposed to X-rays behind The two Solutions? mixed befPre a stepwedge of aluminum. Thereafter the exposed layer i cyan Image consldefably Increased is developed for one minute at a temperature of 20 C. tensity by this after treatment. With phenylhydrazme-3- with the following developing bath: sulfonic acid sodium instead of the phenylhydrazine-Z- sulfonic acid sodium a red image is obtained. p Methy1aminopheno1 5 th 'Ihefidyet image is considerably increased in intensity by Sodium sulfite 40 is a er rea men H dm uinone 6 The layer is finally washed and dried. Since the layer g g carbonate 40 has a very low silver halide content, no fixing is neces- Potassium bromide 1 sary- 1 Water up to 1 liter.

EXAMPLE 5 5 Fixation is not necessary since the coloration by photo- Acolor photographic lti-l d t i l hi h lytic formation of silver in the low silver halide content prises a red-sensitive silver halide emulsion layer conlayer p exposure to y t 1S neghgrbletaining a cyan color coupler, a green-sensitive silver halide Afte? development layer 18 "Ff 2 mmutes 1n emulsion layer containing a magenta coupler, a filter 20 a Solution of the followlng composltlon: layer containing tartrazine as yellow filter dye, and a blue- 50 f 30% aqueous H202 sensitive silver halide emulsion layer containing a yellow 20 of Sodium perborate (or g. Sodium percarbonate), coupler 1s exposed behmd a grey step wedge a sodium carbonate to adjust a pH-value of 10, water up light intensity which is about one-tenth of the amount reto 1 liter quired for conventional processing. The material is then 25 developed for 8 minutes in the conventional manner in Thereafter the layer 15 contacted Y a the color-forming developer of Example 4. mg s fa F i f comams a $9 The layer is treated three times in succession for 1 ppm] is e m e O owmg a 6 or m com minute each alternately with a 2.5% sodium percanbonate 22223 gg jg g fig g g i eacih i solution and the color development solution indicated 30 Per liter p e s e ea g soulon 223:1: gi t; i i ii r iie i gig 1s mtenslfied by this alter. Upon treatment with the last mentioned bath negative After brief intermediate washing and bleach fixing in 31522 the color Shown m the ionowmg table are the followmg bath: The conventional black-and-White development of the Soluti 1; 50 g, N s o i 500 H 0, imagewise exposed silver halide emulsion layer and the soluti 2; 25 K F (cN) i 500 m H (The dye iormation by the catalytic oxidation of the colortwo solutions mixed before use), the layer is washed fermms compounds e311 be accelerated y mereasmg the d 1 -1 1 temperature of the baths. The development and the colorforming treatment can be performed for example at tem- EMMPLE 6 peratures between 40 and 60* C.

A high speed silver bromo iodide gelatin emulsion con- The dye forming oxidation process can be stopped and taining 10% by weight of silver halide, silver iodide the image can be stabilized for storage by aftertreatment content 1 mol percent is applied onto a cellulose triwith an aqueous solution of Na SO NaHSO or acetate support and dried. The emulsion layer contains formaldehydebisulfite.

In combination with pyrocatechol Coloriormer Color color (3H Blaekish brown.

0E Black Black;

l CH;

CH; CH; D0.

Brown Blackish brown;

TABLEContinued In combination with pyrocatechol Colorformer Color color Brown Blackish brown.

( 151 Blackish brown...

()3 Brown D0. @0 OH:

OH do D0. 14 02H:

011 Black Do:

| H1 O(|)H (1)13 Brown.

(|)H Brown Do. @0 OH:

in! do .Blackish brown.

OH Black Black.

()H Blaokish brown... Blackish brown.

CHr-CH=G a OH Black Black:

TABLEContinlued In combination with pyrocatechol Colorformer Color color (I)H Blue Bluish black.

I 0 OH:

?H Greenlsh black..-- Black.

(IE Black Do.

011 .....do Violet black.

Brown Brownish yellow. OH

Blackish brown-.. Blacklsh brown. 3

Brown Browm nofi jon OH ----.d0 Blaeklah brow!- 01 011 ..do Do.-

0H 011 .do........... Brown:

CH: CH: "410 D0;

..do.......... Do: HO OH ()H Black Black;

HO OH OH ----do-. Do:

OH OH TABLE-Coutim1ed In combination with pyrocatechol Colorformet Color color (3H0 Brownish black..- Brownlsh black: @011 (300E .----do D0. BOO-OH (DO-NH: -.-.-do Do. HOQ-OH OH ('10 OH -do Do.

(IJOOH (300E Brown Brown. H0-Q0HQ0H CH; OH;

HO 0H 0 CH- OH:

C0011 C0011 Brownish red.. Do.

HO OH I C10-Cl COOH OH OH COOH Brown Do.

I --OH Black Black.

TABLE-Continued In combination with pyrocatechol Coloriormer Color color Greenish black-.. Black. 0 0 OH Yellow Yellowish green; 0 O OH 0 0 0H Brown Brown:

C 0 0H Blacldsh brown;

0B Brown Do;

8 OIH (I)H -.-..do Brown. @s 0311 (HI -...-d0 Do; s 03H (Hi Blue black Do.

H08 (iHI Violet black Brownish black. 8 Dani-m S 0 11 n; .....de Do.

011 -do Violet black:

Brownish black... Brownish black;

TABLEContinued In combination with pyrocatechol Colorformer Color color (I311 (1H Black Black.

(i7H ...-.do Do.

HO S 0 1H 0H (|)H Blackish brown..- D0.- HO; S 03 S 03H GaH; .....do K- Do;

H O S O H NH: Brownish black.

.3 Yellow brown; NH-

........... Brown;

Brown Brownish black.-

IIIHQ (10. D0

blIH, Reddish brown z L Blacklsh brown Blackish browm D0;

TABLE-43011 tinned In combination with pyrocatechol Colorformer Color color NH, Blackish brown.-.. Reddish brown.

NH-CHO NIH-C O-CHI Browmsh redun- Brown:

Brown. H De:

.--. do......:....- Brown:

.-...do..... Do.-

.-=..dO.=. Do;

.....do. Brownish black:

.-...-::.. Brown:

Black Black:

Blacklsh brown--- Do:

Black- 3:. 3.1.. D 0;

TABLE-Continued In combination with pyrocatechol Colorfonnet Color color ?O;H Btownish b1ack.:- Brownish black:

S 0 H 10.....:::::: D0:

zzzzjomnzzzzz Black: HEN NH:

Cl Bmekish browm: Do: HzN=-NH-=G o=0m omugourzzzzz-z: Brown:

HgN NH:

N O a Reddish brown. D0: HzN- N H-C 0-011! Brow Do: GHQ-C 0-HN NIL-G 0-=-CHr-C 0-011; 5 0-011.

0H| Light red.....:-.:: Black:

?H; Brown. Blackish brown:

CH; Yellow broWn...:-: D0:

NH, Brown. Brown:

(1H :1: .do Blackish brown:

N H-OHO l NH,

CH .d0-...-..:::': D0:

NH-C 0- OH,

TABLE-Continued In combination with pyrocatecllol color Color Colorformer I NH-CO-COOH Black. .113; .2 I; Black.

NHQ

l NHQ Brownmfimufl Browuish black.

.nudocnwulum Brown 1 Nil,

CzHs

Yellow brown N Hr" Brownwnumn Yellow brown:

TABLE-Continued In combination with pyrocatechol Colorformer Color color 0 H Brown Brown. H2N@- Call: NH;

11711: Black w Black;

IIIH do Do.

I NH: 3

NHI NH; 410 DU.

NH: d0.:. ..r.-.:: D0.

-..do Do; HaN NH;

Bluckish brown... Blackish brown; H2N- NH:

CHa Brown Blackish brown:

N0: .--..d0 Brown:

.....110 Do: HaN NHCO0OOH CHa CH: ..d0 Black.-

.....do.. Brown: IzIH 0-8 0: H 0 3 S S 0 3H NH: Black Black.

TABLE-Continued In combination with pyrocatechol Colorformer Color color OH Brown Brown.

w $11 .....(10 Black.-

OH, OH .n Du.

011 do Brownish black.

OH Violet black \iolut black.

OH NH:

O CH:

Brownish black.-. Brownish black.

".wdo

Blackish brown.-. Black.

TABLEContinued In combination with pyrocatechol ColorIormer Color color Blackish brown. Blackish brown.

35 TABLE-Continued In combination Colorful-met Color 331%;- pymeatechol C 0 0H NH: 7:. Black; EGGS o NH-c 0Q 0H; :m. .do 121:: Do

()CzHa Brown Brown:

NH-G 0-011:

0 C m Yellow brown... Yellow bro'wu:

NHW

HQN

OH OH .-d0 Do.

BIN NH;

0H 0H Brown.... Brown:

E G O NH Black Black:

S 0 H .....do....... Do. HzN-Q-NH NH:

CH: CH: .-.d0 Do. EhN NHQNH,

NH: Brownish black... Brownish black:

SOaH

IiIH: -----d0 D0:

SOIH

NH: ....-.fl0 Do: