US1841653A

US1841653A - Process for developing positive diazo prints

Info

Publication number: US1841653A
Application number: US299042A
Authority: US
Inventors: Lodewijk Pieter Frans Grinten; Karel Jan Josef Van De Grinten
Original assignee: Individual
Current assignee: Individual
Priority date: 1927-08-22
Filing date: 1928-08-11
Publication date: 1932-01-19
Anticipated expiration: 1949-01-19
Also published as: DE589875C; GB295993A; BE353508A; FR658977A; NL27513C

Description

Jan. 19, 1932. 1.. P. F. VAN DER GRINTEN ET AL 1,841,553

PROCESS FOR DEVELOPING POSITIVE DIAZO PRINTS Filed Aug. 11, 1928 Inve'n for-s:

L- P. F van Jar GrzQnZe-n and If. :11]. van cler- Grlnten By '0- Attorney Patented Jan. 19, 1932 UNITED STATES PATENT OFFICE LODHWIJ'K 2mm MS van mm GBINTEN AND KARE JAIN JOSE! van nan GBIN'IEN,

or v'nnno, umnnnnmns, Lmnnae, nnmnnmnns ASBIGNOBS TO FRANS VAN DER ORINTEN, OF VENLO,

PROCESS FOR DEVELOPING POSITIVE DIAZO PRINTS Application fled August 11, 1828, Serial No. 299,042, and in the Netherlands August 22, 1827.

It is common knowled e that the positive diazo printin process is used on two properties of the iazo compounds:

() Their sensitiveness to li ht. The diazo 6 compounds are decomposed probably and pn 1lzhe whole into phenols) by exposure to i (b) Their property of forming azo dyes with substances known as azo-dye compo- 10 nents.

Reaction (6 takes place mostly with the co-operation o alkalis. In the photographic diazo printing process, a film containing a diazo compound and generally disposed on aper is exposed to light under a transparent image, drawin or tracing, so that the diazo com ound is ecomposed on those areas of the lm which are reached by light.

An.azo dye is formed in the areas which are unaffected by light (and in which the diazo compound has remained unaltered) by treating the exposed film with an azo-dye component and alkali, while the areas which have been exposed to light remain colourless when treated in this manner. The image is simultaneously fixed, because after being subjected to this treatment (which may be also considered as a developing treatment) the image-forming areas (now containing a dye) as well as the background reached by light, are stable under any further action thereof. The positive diazorinting process does not involve a separate ing operation, which is necessary in most of the other photographic processes and which usually consists in removing either non-decomposed light-sensitive initial materials or certain substances formed by the action of light. In the positive photo graphic diazo printing process, the develop ing operation (which is simultaneously a fixing operation) consists exclusively in an addltion of substances. It is in fact sufiicient to add an alkali for developing purposes when the azo-dye components are initially embodied in the light-sensitive film, this being made possible in practice by using certain diazo compounds such as for example diazo anhydrides. The simplest known manner in which the alkali may be added is to subject the exposed sensitive film to the action of gaseous ammonia, the prints being disposed in a developing tank vcontaining ammonia vapour. The advantage of this method of proceeding is that developing baths are dispensed with, so that the pictures thus developed need not be dried.

This developing method has however the following disadvantages:

(a) The developing operation is comparatively lengthy, especially in the winter. At low temperature, the prints must remain in the ammonia-charged atmosphere for half an hour or more in order to be fully developed.

(1)) When no complicated mechanical apparatus is used, this developing operation is highly tedious because of the unpleasant and lIlJllI'lOllS alkaline vapours.

The developing tanks must therefore he often in the open and the prints developed smell of ammonia for a long time.

These two main disadvantages are the rea son why the diazo printing process with what is known as dry development is not used in practice as widely as the simplicity of the process might have warranted.

The above disadvantages are not to be found in the method of developing diazo prints in baths (described for example in Eders Handbuch der Photographic, 1899, pages 563-565, and in Photographisehe Korrespondenz, 1895, pages 284-285) because (a) the print may be developed in a few seconds, and (b) non-volatile alkalis may be used which evolve no offensive and injurious vapours.

This method however lacks the characteristic advantages inherent in dry development with the aid of vapours. Moreover, a difliculty involved in the use of baths is that the always more or less soluble azo-dyes merge one into the other, with the result that the images obtained are not sharp and the clearness of the background is affected.

The present process has the advantages of both the methods described in the foregoing while their disadvantages are entirely avoided. According to the present invention, an extremely thin layer of an alkaline liquid (which if necessary may contain an azo-d e component) is uniformly spread over the whole area to be developed. Friction may be avoided, in which case the procedure con sists in applying an extremely thin layer of the developing liquid on the surface to be developed. This makes it possible:

(a) To develop in a few seconds;

(6) To avoid offensive vapours by using non-volatile alkalis;

(c) To use a very thin layer of liquid, so that the prints remain dry and the colours do not merge;

(d) To use diazo compounds (by applying the alkaline developer together with the azodye components) which cannot be used (or can be used only under certain conditions) together with azo-dye components in the light-sensitive film, whereby the selection of diazo compounds is very large.

In the accompanying drawing, the single figure is a side view, partly in vertical section, of an apparatus for applying the developer.

This apparatus, which is of extremely simple character, comprises two vertically superposed and rubber-covered rolls a and b, the lower roll 5 revolving in a trough 0 containing the developing liquid and the upper roll bearing on the lower one by gravity or being pressed (hard when necessary) thereon by suitable means such as for example screws (0) acting upon the bearings of the roll. The lower roll is driven while the upper roll is preferably moved at the same peripheral velocity so that there is no friction at the line of contact.

The lower rubber roll 6 collects, while rotating. developing liquid from the trough c and l'fli-I V \'S it to the line of contact of the two rolls. Here the liquid is practically entirely retained and flows back uniformly.

This extremely simple apparatus comprises moreover a small table d disposed in front of the upper roll and fitted with a simple guiding and flattening device 8 to prevent creases from being formed. A stripper may be advantageously provided to prevent the paper from adhering to the rolls. This stripper may be constituted by blades f projecting as far as the grooves g of the rolls.

)Vhen a print is passed between the two rolls with the side to be developed facing dmvmvards, the said side is wetted by the developin liquid for a very short instant'and is pressed between the two rubber rolls immediately after. To this end, the print it is laid on the table (1 with the image side upwards and is pushed between the upper roll a and the flattening device 8; the roll a picks up the print and conveys it through the rolls a and b The print comes out at the other side between the rolls; it carries a sufficient quantity of developer and is practically dry. The chemical development reaction now takes place within a very short time (a few minutes at most) in the film thus treated. There is however no necessity to wait, because the print develops of itself without further supervision.

Four metres of prints may be easily developed per minute when the width is suitable (usually 100 cm.). This rate of operation may be considerably increased by using a very concentrated developing liquid; it is also possible however, to work, if required, at a slower rate by using more dilute developers.

For small installations this simple apparatus may be replaced by smaller, sim ler and cheaper means with the aid of whic it is likewise possible to provide the light print with a uniform thin layer of developing li uid.

he developers which may be used according to this invention are aqueous solutions of 35 alkalis or alkaline-reacting substances, mixed if necessary with azo-dye components such as phloroglucinol, resorcinol, resorcinie acids, naphthols, phenols, naphthol-sulphonic acids and the like. Should the light-sensitive film be devoid of substances preventing the prints from turning yellow, such substances may also be added to the developer.

The substances which prevent the prints from turning yellow may be incorporated in the light-sensitive film as well as in the developing liquid. As a general rule, reducing substances which are stable in an acid medium are preferably used in the. lightsensitive film and those which are stable in an alkali medium are used in the developing liquid.

The alkaline substances used may advantageously be potassium carbonate, sodium carbonate and ammonium carbonate (the latter not so much to be recommended because it has a smell of ammonia) preferably mixed with buffer salts such as secondary phosphates, secondary citrates and generally salts of polyvalent weak acids and the like.

Bufl'er salts are salts by which the intensity of the alkaline reaction is decreased without affecting the potential alkaline reaction, especially salts of polyvalent acids, such as phosphoric acid, citric acid and the like, and salts having a neutral reaction, such as secondary sodium phosphate; which salt, for instance, if added to an alkali solution, forms tertiary phosphate. Said salt has an alkaline reaction, but in the presence of an excess of secondary salt the concentration of the OH-ions, which causes the intensity of the alkaline reaction, is very considerably decreased with respect to the original alkali solution and yet its alkaline action (capacity 1 of neutralizing acids) remains the same.

In order that the printing may be as uniform as possible, a wetting agent such as alcohol, glycerine, Turkey-red oil and the like may be added to the developing liquid.

Ewample 1.-Prints obtained by exposing diazo-printing paper the light-sensitive film of which contains 1.dimethylamino.2.chlorobenzene.4.diazonium chloride, or 4.diethylamino-benzol-diazonium chloride are printed with a developer by bein guided between the rubber-covered rolls escribed in the foregoing. The said developer is an aqueous solution of 20 parts by weight of otassium carbonate, 30 arts by weight of 'sodium phosphate an 1.2 parts by weight of phloroglucinol, so that the print is developed. Positive images are thus obtained in dark to black colour on a light background. In the developer, the 1.2 parts by weight of phloroglucinol may be rep aced by 4 parts by weight of resorcinol, 5 parts by weight of fl-naphthol, 5 parts by weight of B-oxy-naphthoic acid anilide, 3 parts by weight of 2.7.dioxynapthaline and the like. These are then dissolved in quantities of soda lye sufficient for dissolution and yield images in various dark colours.

In a similar manner, the otassium carbonate may be replaced by so ium carbonate or ammonium carbonate while disodium phosphate may be replaced by disodium citrate or the like.

The following may be added to the developer to prevent t e print from turning yellow: 0.4% of formalin or 1% of urotropin and the like' or 5% of glucose, 2% of sodium lactate, 0.1% of pyrogallol.

The uniform spreading of the developer on the pa r is assisted with 5% of methylated alco 01 or 3% of glycerine or 1% of T urkey-red oil and the like.

Example Q.A solution is made, which contains 1.8% of 1.diethyl-aminobenzoL4.diazonium chlorostannate and 1% of potassium sulphate. The solution is spread on paper and the like, and dried. After exposure under a drawing of transparent paper, a thin layer of an aqueous solution of 5% of potassium carbonate, 0.5% of phloroglucinol, 0.5% of resorcinol, 10% of potassium chloride, 10% of sodium citrate, 10% sodium hyposulphate and 10% of glucose is uniformly spread over the whole surface of the rint with the apparatus shown. An entirely lack picture is obtained, which is very stable against any tendency to become yellow, which would not be the case without the reducing means (citrate, h posulphite and glucose).

Example 3. thin layer of a developing liquid constituted by an aqueous solution of 40 parts by weight of potassium carbonate and 60 parts by weight of disodium phosphate is spread as in Example 1 on prints obtained by exposing diazo printing papers containing 1.5 parts by weight of 2.7 .dioxynaphthaline and 3% of oxalic acid to 5 parts by weight of 1.dimethylamino.3.5.xylol.4.diazonium chlorostannate; or 0.5 parts by weight of phloroglucinol and 3% of oxalic acid, or 1.5 parts by weight of triketohexamethylenetrioxym, 0.3 parts by weight of hydroxylamine chloride and 2 parts by weight of tartaric acid to 5 arts by weight of 1.dimethylamino.3.5.x lo .4.diazonium chlorostannate; or the hy roxylamine compound of 0.2 parts by weight of phlorogluclnol and two parts by wei ht of tartaric acid to 1.5 arts by weight of dimethylaminobenzene.4. iazonium chlorostannate; or combinations of these BXamElES. All methods of printin described in xample 1 are also ap lica le to the present example.

mample 4.Prints obtained by exposing diazo prlnt papers made of diazo anhydrides with azo dye components are printed as in Examples 1, 2 or 3 and treated with a developer as in Example 3. All methods of printing described in Example 1 are applicable to this example.

What we claim is 1. The process for developing direct positive diazo prints which consists in impressing upon the surface to be developed an alkaline liquid containing an azo-dyestuif component and a reducing agent non-decomposable by alkali, in the form of a uniformly thin film.

2. The process for developing direct positive diazo prints which consists in impressing upon the surface to be developed an alkaline liquid containing an azo-dyestufi' component and a buffer salt, in the form of a uniformly thin film.

3. The process for developing direct positive diazo prints which consists in impressing an alkaline liquid containing an azo-dyestufl component in the form of a uniformly thin film upon an exposed surface having a diazo compound therein, said film containing the azo-dyestuff component in an amount not substantially in excess of that required to couple with the diazo compound.

4. The process for developing direct positive diazo prints which consists in saturating throu hout its entire area the exposed surface 0 said prints with a developing liquid containing a non-volatile alkaline substance by spreading said liquid on said surface in the form of a uniformly thin film, the quantity of the developing liquid con. tained in the film being substantially corre sponding to that required to effect development of said surface.

, 5. The process for developing direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid con taining a non-volatile alkali and a buffer salt by spreading said liquid on said surface in the form of a uniformly thin film, the quantity of the developin liquid contained in the film being substantia ly corresponding to that pequired to effect development of said surace.

6. The process for developing direct positive diazo prints which consists in saturating throu hout its entire area the exposed surface 0 said prints with a developing liquid containin a non-volatile alkaline substance and a re ucing agent non-decomposable by alkali by spreading said liquid on said surface in the form of a uniforml thin film, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of saidcsurface.

7. The rocess according to claim 6 wherein the red iicing a cut is a thiosulphate.

8. The process or developing direct positi ve (liazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkaline substance, an azo d estufi' com onent, and a reducing agent nonecomposab e by alkali by spreading said liquid on said surface in the form of a uniformly thin film, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said surface.

9. The process according to claim 8 wherein the reducing agent is thiosulphate.

10. The process for developing direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkaline substance and a wetting agent by spreading said liquid on said surface in the form of a uniformly thin film, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said surface.

11. The process for developing direct positive diazo prints containing a diazo compound of the type which can not be used together with azo-dycstutf components in the light sensitive layer which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkaline substance and an azo-dycstnff component by spreading said liquid on said surface in the form of a uniformly thin film, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said surface.

12. The process for developing direct positive diazo prints containing a diazo compound of the type which can not be used together with azo-dyestnll' components in the light sensitive layer which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkali, a buffer salt, and an azo-dyestufl' component by spreading said liquid on said surface in the form of a uniformly thin film, the quantity of the developing liquid contained in the film being stantially corresponding to that required to efi'ect development of said surface.

14. The process for developing direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkali and a buffer salt by momentarily wetting the exposed surface with an excess of said developing liquid and removing the excess immediately thereafter, so as to depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said surface.

15. The process for developing direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkaline substance and a reducing agent non-decomposable by alkali by momentarily wetting the exposed surface with an excess of said developing liquid and removing the excess immediately thereafter, so as to depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said surface.

16. The process for developing direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkaline substance and an azodyestuif component by momentarily wetting the exposed surface with an excess of said developing liquid and removing the excess immediately thereafter, so asto depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said Surface.

17. The process for developing direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkali, a buffer salt and an azodyestulf component by momentarily wetting the exposed surface with an excess of said developing liquid and removing the excess immediately thereafter, so as to depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect developmentof said surface.

18. The process for-developing direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with' a developing liquid containing a non-volatile alkaline substance, an azodyestufl' component and a reducing agent non-decomposable by alkali by momentarily Wetting the exposed surface with an excess of said developing liquid and removing the excess immediately thereafter, so as to depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said surface.

19. The process for developing direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkaline substance, and a wetting agent by momentarily wetting the exposed surface with an excess of said developing liquid and removing the excess immediately thereafter, so as to depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said surface.

In testimony whereof we affix our signatures.

Dr. LODEWIJK PIETER FRANS van der GRINTEN. Dr. KAREL JAN JOSEF van der GRINTEN.

Ring the excess immediately thereafter, so as to depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being sub stantially corresponding to that required to effect development of said surface.

18. The process fordeveloping direct positive diazo prints which consists in saturating throughout its entire area the exposed surface of said prints with a developing liquid containing a non-volatile alkaline substance, an azodyestuff component and a reducing agent non-decomposable by alkali by momentarily Wetting the exposed surface with an excess of said developing liquid and removing the excess immediately thereafter, so as to depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being substantially corresponding to that required to effect development of said surface.

19. The process for developing direct positive diazo prints which consists in saturating throughout its entire area the ex osed surface of said prints with a developlng liquid containing a non-Volatile alkaline substance, and a wetting agent by momentarily wetting the exposed surface with an excess of said develo ing liquid and removing the excess imme lately thereafter, so as to depose a uniformly thin film of said liquid to said surface, the quantity of the developing liquid contained in the film being substantially corresponding to that required to eflect development of said surface.

In testimony whereof we affix our signatures.

Dr. LODEWIJK PIETER FRANS van der GRINTEN. Dr. KAREI. JAN JOSEF van der GRINTEN.

DISCLAIMER 1,841,653.Lodewi'k Pieter Frans van der Grinten and Karel Jan Josef van der PROCESS FOR DEVELOPING POSITIVE Dmzo 19, 1932. Disclaimer filed September 12, runing Company, Inc.

Hereby enters its disclaimer of claims 7 and 9 of said patent.

Grinten, enlo, Netherlands. PRIN'rs. Patent dated Januar 1934, by the assignee, Charles [Qfl'icial Gazette October 9, 1934.]

DISCLAIMER 1,841,653.Lodewik Pieter Frans van der Grinten and Kar Grinten, enlo, Netherlands. PROCESS PRINTS. Patent dated Janua 19, 1932. Disclaimer filed September 12, 1934, by the assignee, Charles rum'ng Company, Inc.

Hereby enters its disclaimer of claims 7 and 9 of said patent. I Gazette October .9, 1934.]

el Jan Josef van der Fon DEVELOPING Posrnvn Dmzo