PERMANENT COLOR PHOTOGRAPHIC PICTURE

Abstract: A permanent color photographic picture obtained by forming a latent image on a base plate durable against high­ temperature baking utilizing the art of light-sensitive resin, forming an image according to dry development using a toner containing an inorganic pigment, and baking at high tempera­ ture; and a process for obtaining the picture. This process involves an easier baking step than that in conventional wet process development, and is extremely advantageous for producing permanent color photographic picture. A very excellent image quality can be attained by subjecting the light-sensitive element to an image portion-swelling step prior to the development step, and color images can be obtained, if desired, by providing the baking step merely once in the last stage of the whole processing. In this case, suffi­ ciently good color reproduction can be attained by selecting a proper combination of pigments. The resulting permanent image is absolutely different from the obtained by conven­ tional printing art in that it has good resolution and gradation as well as good color reproduction.

Description: Permanent Colour Photograph Echzrt Description This invention relates to a permanent colour photograph. More particularly this invention relates to a colour photograph which contains no organic materials and can be conserved permanently, and also relates to a method of manufacturing the same. Background of the Invention Recently, photography has made great progress together with an increase of a demand for photographs, especially colour photog > . However, as a photographic image was formed in an organic materials, and as colour images were reproduced using organic dyes, the conservation of the photographic images are limited in spite of the improvements on their heat- and moisture-resisting properties or light resistance, or despite the development of a method to protect their surface with a resin layer such as an acrylic resin layer. In order to solve this problem, it has been known to print an image in intaglio or with screen on a ceramic plate using inorganic pigments and fire the plate to produce a permanently preservable reproduction. According to this method, however, it was impossible to obtain the same resolution and tone reproduction as those in photographic reproduction. Especially this problem was serious in compara tively small images. These known printing techniques had a restricted application since they needed printing apparatuses and special techniques. Moreover, firing temperatures for colour reproduction had to be adjusted individually depending on each pigment, and the firing process had to be repeatedly carried out beginning with a pigment which needed the highest firing temperature. The whole procedure was, therefore, complicated and colours to be reproduced were limited. It has been also known to form an image by hardening a non-image part of a light hardening element and developing the unhardened and tacky image part with a toner, or to form a colour image by providing further the light hardening element over the obtained image and repeating the same procedure as above (e.g., U.S. Patent No.3,649,26B). In this case, it is possibl to develop an image using inorganic pigments so that the colour of the image obtained would not change or fade. However, since substances which support the pigments are organic matter, the obtained image can not be permanently preserved as they are. Another known method is to expose imagewise photosensitive resin provided on a ceramic plate, develop the image with a slurry containing inorganic pigments and fire it to produce a monochromatic permanent photograph. When many layers of an image are formed and fired according to this method, solvent molecules constituting a slurry remain in the photosensitive resin and evaporate during the firing process to destroy the image. It is, therefore, impossible to form a colour image by a single firing process. Besides, no combination of pigments that can give a preferable colour reproduction by a single firing process has been known so far. The present inventors made various studies to solve the above-mentioned problems and discovered that, when particles of inorganic pigments are let adhere to a photosensitive element which has been exposed imagewise beforehand (dry development) and the developed image is fired under certain conditions, the photosensitive element disappear very easily and a permanent photographic image of good quality can be obtained. The inventors also discovered a combination of pigments having almost the same melting points which are able to reproduce excellent colour. Accordingly, the primary object of this invention is to provide a permanent colour photograph which causes no colour fading and/or changing and has an excellent resolution, tone- and colour reproduction to give an image of good quality. Another object of the present invention is to provide an easy process for producing a permanent colour photograph which causes no colour fading and/or changing and has an excellent resolution, tone and colour reproduction. The third object of this invention is to provide a firing process which is suitable for producing a permanent colour photograph with an image of good quality using a ph,o tosens i t i ve element. Disclosure of the Invention The present invention provides a permanent photograph having a colour image which comprises inorganic pigments on a base plate consisting of an inorganic material and/or metal, and method for providing it. It is characterized by the following two processes: (A) A process for forming a colour image by repeating at least the procedures (a)-(c) (a) providing a photosensitive element on a base plate consisting, at least, of an inorganic material and/or metal, (b) exposing imagewise the photosensitive element through a directly screened lithographic film, and (c) dry developing the image with a toner containing inorganic pigments, and ( process-òr- c for dissolving the p; ;hotosensltive element and at the same time fusing the inorganic pigments to the base plate by firing at higher than 400'C, at least2 after the final develop ment in the above. The base plate used in this invention can be of any materials so far as it can stand heating at higher than 4000c . They are, for example, china and porcelain materials1 other ceramic materials, inorganic materials such as a glass plate having a high melting point, or plates of iron, aluminium, copper and other metals or alloys. Plates of inorganic materials and those of copper or silver are prefer able sWinc-e inorganic pigments that are to form an image can directly fuse to them. From the economical viewpoint, plates of inorganic materials are more preferable. In the case of iron or aluminium plates, it is desirable to provide an under coat-ing -over the plates to fix the pigments effectively on the plates, or to mix the pigments with additives mainly containing silica in order to make the thermal expansion coefficient of an image part and that of the base plate almost--the same. A base plate can be coated with a photosensitive element using a brush or a roller, or it can be soaked in a solution containing the element and dried by hanging. Other usual methods to provide a photosensitive layer on a printing plate, such as spraying the plate with a solution containing a photosensitive element or sprinkling the solution over the plate with a wheeler, can also be used. As a photosensitive element, in this invention, any of the photosensitive compounds that rapidly change their chemical and/or physical properties when they are exposed to light are usable, e.g. a high molecular compound having reactive groups which undergoes polymerization or crosslinking reaction when exposed, a mixed compound of a nonreactive polymer and a monomer which can carry out a photopolymeriza- tion react-i-on, -or a high--mo-lecular compound containing polymer and an agent that crosslinks said polymers. Examples of such photosensitive compounds are gelatin or albumin mixed with diazonium salt or dichromate, photosensitive resins such as cinnamic acid ester of polyvinylalcohol which has a photosensitive cinnamoyl group, the so-called photosensitive rubber solution having a photosensitive azide group, photosensitive nylon having a photosensitive acryloyl group, unsaturated polyester containing a crosslinking agent such as acrylamide, nonreactive macromolecules such as cellulose ethylate mixed with acrylic acid derivatives which carry out a photopolymerization reaction, or quinone diazides which become soluble in an alkaline solution when exposed to light. If metals are contained in such a photosensitive element, they might obstruct a colour reproduction of an image after its firing. Therefore, the elements containing no metals are preferable-for example2 photosensitive compounds mainly consisting of photo-hardening resins such as polyvinyl cinnamate group (e.g., KPR marketed by Eastman Kodak Company, TPR by Tokyo Ohka Kogyo Co., Ltd., SPR by Sambo Chemical Research Lab.), polyvinyl cinnamyridene acetate group (e.g. KOR marketed by Eastman Kodak Company), polyvinyl p-azidobenzoate group (e.g., FPER marketed by Fuji Yakuhin Kogyo Co., Ltd.). It is possible to add, if necessary, the so-called well-known sensitizer to the above-mentioned photosensitive compounds in order to improve their sensitivity, and to provide an adhesive layer between the base plate and the photosensitive layer so that development is carried out effectively. In this invention, when photo-hardening compounds are used as a photosensitive element, imagewise exposure is carried out using a positive film, while in the case of using photo-decomposing compounds, a negative film is used. Especially to obtain a colour image, it is necessary to use a directly screened and colour separated negative or positive film. As to then exposure, although any kinds of light sources that are generally applied for an exposure of photosensitive resin can be used, e.g., a high pressure mercury lamp or an ultra high pressure mercury lamp, especially the so-called metal halide lamp are desirable. In addition to an ordinary imagewise exposure with these lamps a certain amount of full exposure improves the tone reproduction of a shadow part. The present invention2s development after the exposure can be carried out using a toner containing inorganic pigments without any previous treatment when tackiness of the surface of a photosensitive element is varied by its exposura. However, not only when the element does not show any change of tackiness on its surface after its exposure, but also even when the tackiness varies, it is desirable to develop images with a toner after maintaining the exposed p-late in an atmosphere of solvent vapor or after spraying the exposed photosensitive element with a solvent to make the image part swell so that the said part's toner acceptability can be adjusted. These processes may be effective to secure uniform development and to obtain an image of good quality with an excellent resolution and tone reproduction. Therefore, in the case that a photo-hardening element is used, it is preferred to maintain the plate in an atmosphere of a solvent or spray the element with the solvent that can make the nonhardened element of an image part swell or dissolve. While, if a photosensitive element of which solubility varies due to photolysis caused by its exposure is used, it is preferable to use the solvent that can make the exposed part of the element swell or dissolve. However, in the latter case, it is possible to develop an unexposed part by using a solvent that can make the said part swell but can not swell an exposed part. Thus, when quinone diazide, of which solubility varies as a result of its photolytic reaction, is used, both wegative and posit-ive films- -are able Xto-use¯by- choosing a solvent in the swelling treatment before development. Also, not only a positive image but also a negative one can be easily obtained. To be more concrete, when quinone diazide is exposed using a negative film, a positive image can be obtained by making an image part swell with steam after the exposure and developing the exposed part with a toner, while a negative image can be also obtained b > making a non image part swell with vapor of an organic solvent after the exposure and developing the said part with a toner. In this invention an adjustment of the photosensitive element's toner acceptability is carried out at 5 C ¯ 60 C, preferably at 1O.C 40t , though the temperature depends on the kind of a photosensitive element and of a solvent used. A solvent (utilize adjusting the above-mentioned ability before development) ca-n be suitably chosen from those that can make an unexposed part of the photosensitive element swell if the element used is photo-hardening type element. On the other hand, if the element used is that of photodecomposing type, a solvent that can make either an exposed part or an unexposed part swell can be selected. When, for instance, photosensitive resin belonging to polyvinyl alcohol group having a cinnamoyl group is used as a photosensitive element, such a solvent as xylene, toluene, ethyl acetate or n-butyl acetate can be used for making the element swell for the purpose of adjusting its toner acceptability before development. Especially, n-butyl acetate is preferable in the present invention. Also, it is possible to use a mixture of two or more of these solvents, or to prepare a mixture with other solvents that can adjust the swelling effect. Thereby a subtle control of the said toner acceptability becomes feasible. In the present invention the desirable thickness of a photosensitive element to be applied on a base plate is 0.5 preferably 10 .lu.,.. If p. If a lay-er of the element i-s too thin, sufficient image density can not be obtained. While, if the layer is too thick, it tends to become uneven and to cause an image lacking in uniformity. Thick layer also results in a undesired prolonged time for drying the photosensitive element, for adjusting tts toner acceptability before development, or for firing it to dissolve the photosensitive element and let inorganic pigments of the image part fuse on the base plate. The development of this invention can be carried out by sprinkling or spraying a slurry containing pigments over a photosensitive element after its exposure, or by wiping the image, which has been made swollen with a solvent or its vapor, with a piece of cloth or fur holding a powdered toner. In the former case, it is necessary to disperse pigments in a dispersing agent (e.g., an alcoholic dispersant such as methanol, isopropyl alcohol or n-butyl alcohol) which is able to adjust the image density. Then, a process for adjusting the toner acceptability of an image part can be omitted. However, the use of a slurry makes the development procedure complicate and tends to cause an uneven image. Moreover, when a many layered image is to be fired, evaporation of a solvent contained in a slurry may destroy the image. On the other hand, development using a powderd toner gives better results. Dry development is a method in which a dry piece of cloth or fur is used -either in an atmosphere of solvent vapor for making the image part swell or in an atmosphere substantially without the presence of the vapor, or the method to develop the image by passing through a developing room where the toner is being flown in a stirring atMosphere. Therefore, uniform development with an excellent resolution is attainable with dry development. if the development is carried out under a suitable pressure or if the stirring of the atmosphere is controled. The results are especia l ysa tisfac tory- wbn these developments are carried out in an atmosphere of the solvent vapor which can swell image parts. Consequently, the concept of dry development 5 10 15 20 25 in the present invention includes the development using a toner adsorbing the solvent vapor in an atmosphere of said vapor which makes an image part swell. Since pigments used in this invention can be any of thole which do not dissolve akay under heating at higher than 5ao all inorganic pigments are usable. In this case, colouring technique in the field of industrial art is referred to. To give fine magenta colouring after heating at higher than 500 C, the corresponding overglaze colour used in the ceramic art is particularly suitable. Therefore, it is preferable to use the overglaze colours for cyanic, yellow and black colouring that are necessary for a colour image reproduction, as they contain pigments which have nearly the same melting points to that of said overgraze colour for magenta. This is important in carrying out a firing process, especially in producting a permanent colour photograph by a single firing process which will be described later. It is well-known that overglaze colours are comprised of leadglass frit as a flux and pigments of inorganic metaloxides as a colouring substance. In this invention frits that contain no feldspar, especially those of K2 O, PbO-SiO system and Nan 0, PbO-Si02 system are preferred. As to pigments, the followings are desirable: as cyan colouring a mixture of KAIHEKI and TANSUISHOKU which contain cobalt oxide as a substance giving cyan colour, as yellow colouring OHSHOKU which contains antimony oxide and/or cadmium as a substance giving yellow colour, as magenta colouring SHOENSHI which contains Cassius purple and gold as substances giving magenta colour, and if necessary MARON may be added into SHOENSHI, and as black colouring TSUYAGURO. The mixing ratio of KAIHEKI and TANSUlSHOKU (KAIHEKI/TAKSUISHOKU) is 3/21/6, preferably 1/1-1/5, and that of MARON and SHOENSHI (MARO,'N/SH0ENSHI) is 1/15-1/2, preferably 1/101/3. Examples of the pigments used in the present invention are as follows: (1) OHSHOKU (unit: weight%) EMI10.1 <tb> <SEP> Pigment <SEP> (1) <SEP> (2) <SEP> (3) <SEP> (4) <tb> <SEP> Component <SEP> (1) <SEP> (2) <SEP> (3) <SEP> (4) <tb> <SEP> SHIRATAMA <SEP> 39.0 <SEP> 40.0 <SEP> 30.0 <SEP> 36.3 <tb> <SEP> TOHNOTSUCRI <SEP> 47.0 <SEP> 44.0 <SEP> 56.0 <SEP> 45.4 <tb> SINOOKA <SEP> 12.0 <SEP> 13.0 <SEP> 13.8 <SEP> 7.3 <tb> BENIGARA <SEP> 0.8 <SEP> 0.8 <tb> <SEP> TOHJIROME <SEP> 1.2 <SEP> 2.2 <SEP> 0.2 <SEP> 11.0 <tb> (2) SHOENSHI EMI10.2 <SEP> Pigment <tb> <SEP> Component <SEP> (1) <SEP> (2) <SEP> (3) <tb> <SEP> SHIRATAMA <SEP> 71.0 <SEP> 16.0 <SEP> 62.5 <tb> TOHNOTSUCHI <SEP> 1 <SEP> 4. <SEP> 5 <SEP> 3 <SEP> 4. <SEP> 0 <SEP> 1 <SEP> 2. <SEP> 5 <tb> HINOOKA <SEP> 1 <SEP> 4. <SEP> 5 <SEP> 1 <SEP> 2. <SEP> 5 <tb> <SEP> BENIGARA <SEP> 1 <SEP> 6. <SEP> 0 <SEP> 1 <SEP> 2. <SEP> 5 <tb> <SEP> Borax <SEP> @ <SEP> <SEP> 3 <SEP> 4. <SEP> 0 <tb> <SEP> Pure <SEP> gold <SEP> small <SEP> amount <tb> ( 3 ) TSUYAGURO (nearly equal to Gloss Black) EMI10.3 <tb> SHIRATAMA <SEP> 5 <SEP> 8. <SEP> 0 <tb> TOHNOTSUCHI <SEP> 2 <SEP> 0. <SEP> 0 <tb> SHIROSIDORI <SEP> 2 <SEP> 2. <SEP> 0 <tb> Chemical composition of the above listed component are as follows: HINOOKA: SiOZ 99.89% TOHNOTSTCHI: PbO 86.42% CO2 . . . . . 11.60% H2O . . . . . 2.00% SHIRATAMA: SiO2 49.05%, CaO 0.62% PbO . . . . 36.91%, K2O . . . . 11.85% Fe2 O3 + At2O3 . . 0.50%, Na 20 . . . 0,65% BENIGARA (nearly equal to Indian Red): Si02 . . . . . 7.51%, Fe2O3 . . . . 88.57% Al203 . . . . 1.49%, H20 . . . . 2.31% TOHJIROME: almost pure antimony oxide SHIROMIDORI: basic copper carbonate (4) MARON Cassius Purple Base . maroon base containing 1.555g of gold maroon base . purple base containing tin and gold in a ratio: tin/gold = 1/4 Ag2CO3 . . . . . . 1.037g Amount of the solvent and the type of the base . 373.2g of maroon Composition of the solvent ; . maroon solvent minium . . . . . . 6 parts flint glass . . 2.5 parts Boric acid . . . 8 parts (5) KAIHEKI gray Cobalt Oxide . . . . . 20.0% aluminium hydroxide . . . . 74.8% Zinc Oxide 5.2t Colour base of KAIHEKI can be prepared by heating a mixture of above materials at 1300 C in an oxidizing atmosphere. Some of the flux to obtain excellent colour of KAIHEKI using above colour base is shown below: Example of the flux used for KAIHEKI minium . . . . . . . 50% boric acid 38.8% zine oxide . . . . . . . 2.5% potassium carbonate 8.7% (6) TANSUISHOKU TANSTISHOKU is prepared by adding zircon andior copper carbonate to light KAIHEKI so as to make the colour near to the so-called turquoise blue. An example of the composition for TANSUISHOKU is: base frit . . . . 86.5%, antimony oxide . . . . 1.0% tin oxide . . . . 7.5%, copper oxide . . . . 0.6% kaoline . . . . 4.0%, cobalt oxide . . . . 0.1% An example of a preferable composition for the above base frit is: minium 34.0%, feldspar 12.0% quartz . . . . 24.0% limestone . . . . . 7.0% borax . . . . 18.0% kaoline . . . . . 5.0% Sinc-e the particle diameter r o tht torfr usud in this nvention is about 0.28#30@, inerganie pigments or their mixture can tf ued as they are. Th i diameter determines the resolution of an image finally obtained, Which is posse hle hy 175 line pairs/inch. In the present method the surface cf said particles can be covered wi th resin or treated k i th a surface active agent so that they can easily adhere to the swollen image part. Such an adjustment of the adhesive abilits of the tener is important not only for improving the gradient of an image but also for improving the working process of the preseal invention smoothly. The surface active age can @e from any cationie, anionic or non ironic ones d denuding Cr 1 k e kind of the pigments and/or photosensitive element te he used. Non ionic surface active agents, especially polyox@ ethylene alkyl ethers, are suitable for the pigments that impart cyan and yellow, and the same surfactant group, especially polyoxyethylene sorbitane laurates, are suitable for those that impart magenta and black. For the pigments that impart cyan, yellow and black, an addition of caproic acid is also quite effective. Furthermore, it is preferable to maintain powdered toner in solvent vapor which can shell an image part of a photosensitive element, since the solvent adsorbed on the surface of pigments improves the toner's adhesion to an image part and results in obtaining an image of excellent and uniform gradation. Generally speaking, a mixing of at least cyan, yellow and magenta is necessary for the colour reproduction of an image. An adition of black improves the coi@@@ reproduction and many other colours are needed for securing its accuracy. In the present invention, piamenis of e@@ colour are applied on an image part one colour after anether. Therefore, the colour reproduction is carried out by repeating the preparating the photosensitive Ia er exposing with separate colour separation records, and toner developing in sequence. In this case, if flesh colour is chosen as a standard of colour reproduction, it is preferable to form images in an order of cyan, yellow, magenta and black respectively. Excessive pigments adhered during a developing process can be removed off by washing them with a solution or by wiping them with a piece of dry cloth or fur. The former method gives a good image with a low fog density. but if the firing is not carried out after each image formation washing process using a solution is not suitable1 since molecules such as those of water and other solvents (which have penetrated into the photosensitive element) evaporate due to the heat generated during the second or later drying or exposing processes. This evaporation may cause blisters and the image may be destroyed. Therefore1 it is preferable to select the latter method wiping off with a piece of cloth or fur etc., especially chamois is preferred. The colour image obtained as above is fired with its base plate at higher than 400 C and a permanent colour photograph is obtained. When a piece of glass of which softening point is about 400t is used as a base plate, the firing temperature is about 40O't. In this case, although pigments may not melt completely, they are fixed on the plate as its surfase is softened by heat. Adhesion between the base plate and the pigments can be strengthened by adjusting their heat expansion coeficient-for example1 by adding a suitable additive to the pigments (e.g., fine powder of the base glass) to make their coefficient of thermal expantion near to that-of the base plate. If such a material as a ceramic plate which has an extremely high melting point is used as a base plate, the firing process is to be carried out at higher than 500C, , prefera,bly at higher than 550 C, which is high enough -to¯melt pigments and let other firmly fix to- the base plate. It is possible to increase the firing temperature to around 1300C when pigments with high melting points, e.g., so-called underglaze colours used in the industrial arts, are chosen. However, in order to reproduce good magenta colour by using overglaze colours, firing is to be carried out at 500t h 850'C, preferably at 600'c -- 750 C. During this firing process organic matters other than the pigments dissolve away completely. It is not good to raise the temperature rapidly, since the pigment will come off to damage the image to be formed. Therefore, the firing process should be carried out particularly carefully until the temperature reaches to a degree where a photosensitive element dissolves away. Since most of the photosensitive elements dissolve away at around 200 0c , the desirable rate of temperature increase from the room temperature to about 200t is less than about 4t/min., preferably less than about 3%/minute. The most reliable method for producing a permanent colour photograph is to provide a photosensitive element newly over the surface of the firstly prepared permanent photograph and repeat the same procedure as the first one. Thus, colour images at least in cyan, magenta and yellow, and preferably black, are prepared and permanent photograph is obtained. But this process is complicated as each monochromatic permanent photograph is placed one over another. In the case that pigments having nearly the same melting points are used: firing processes can be reduced to only once after the final developing treatment to avoid above complication. The first method for this is to harden non image part of a photosensitive element sufficiently by exposing the whole element after its developing treatment, then new photosensitive element is applied over the resultant surface for a new colour image. The second method is to use a thermosetting compound as a photosensitive element. In this cases said element, after its de-vel-opment, may be heated to certain extent so that the obtained image should not get any adverse effect when new photosensitive element is recoated on the first image. These two methods can be practiced in combination as well. Thus, it is possible to simplify the whole procedure by replacing each firing process after the developing treatment with a whole exposing process and/or a heating process. Another method for avoiding the complication of the firing process is to provide an intermediate layer between each photosensitive element layer as will protect the already formed image from any effect of the application of a new photosensitive element. When a photosensitive resin which is nsol ubl e in water but soluble in an organic solvent. such as cinnaic acid ester of polyvinyl alcohol, is used as a photosensitive element, the surface of the element after its development is coated with a film of water soluble polymer such as polyvinyl alcohol or polyvinyl pyrolidone, then the photosensitive element is newly applied over said film. On the other hand, when a photosensitive element mainly consisting of water soluble photosensitive resin is used, a water insoluble polymer (such as ethyl cellulose) may be provided as an intermediate layer. Among the above-mentioned methods for avoiding the complication of the multi-firing-process, the method to use the thermosetting photosensitive element is particularly desirable in view of its practicability and excellent image reproduction. Thermosetting photosensitive elements usable in the present invention are, for example, photosensitive polymers having an ethylenically double bond that can conduct thermopolymerization, a photosensitive element including monomers having an ethylenically double bond which is able to polymerize by heat, or photosensitive element that can conduct thermal crosslinking. In the case that multicolour images are melted to fix the image on a base plate by a single firing, it is important to pay particular attention to the destruction of the image caused by an organic matter when it dissolves away. Such a risk may be reduced by disolve the polymer of upper layer faster than that of lower layer substancially; which may be realized by heating the layered element in an oxygen rich atmosphere, or by using polymer having smaller polymerization degree as polymer which is contained in photosensitive element to be newly applied or as polymer to be provided as an intermediate layer, than that of the previous layer. DESCRIPTION OF THE MOST PREFERRED EMBODIMEN'T The following examples are provided to illustrate present invention, but are not to be construed as limiting present invention in any way. Example 1 A photosensitive element mainly consisting of cinnamic acid ester of polyvinyl alcohol was applied on a ceramic plate with a size of Ilcmxllcr to have a thickness of about 5 p on dry base. Then the element was exposed to a metal halide ultra high pressure mercury lamp ( lkw ) with a distance of 50cm during 75 seconds through a directly screened positive film, then whole surface was exposed for 2 seconds through a filter having a transmission rate of 10%. The obtained ceramic plate was exposed to saturated vapor ( 25 C) of n-butyl acetate for 5 minutes to make the image part of the element swell and developed with a soft cloth carrying as pigments a mixture of KAIHEKI and TANSUISHOXU ( KAIHEKIITANSUISHOKU = about 0.80 ; both are produ-ced by ISEHISA Co., Ltd.) of overglaze colours used in the industrial arts. Excessive pigments were removed with chamois leather. The resultant cyan image formed on the ceramic plate had a good- reso-lution -a-nd gradation. The above ceramic plate was placed in a furnace of an oxidizing atmosphere at the room temperature. The tempera ture was raised to 200t in a rate around 2C/minute, then further raised to 650t so that it reached after 70 minutes. As a result, the layer of the photosensitive element had dissolved away completely and the pigments had fixed firmly into the base plate. The obtained permanent photograph had a tolerable cyan image with a reproduction of resolution and gradation as good as those in ordinary photographs. The same whole process as above was repeated to prepare a yellow image over the cyan one using OHSHOKU produced by Colour Shop KAJITA & Company and obtained a permanent photograph of an image in cyan and yellow. A magenta and a black images were formed over the cyan and yellow images in the same procedure as above respectively using SHOENSHI and TSUYAGURO-both produced by ISEHISA Co., Ltd.. The resultant permanent colour photograph had an image with an excellent resolution and gradation. Also, its colour reproduction was almost satisfactory. Example 2 A permanent colour photograph was prepared in the same manner as in Example 1 except that a mixture of (a) KAIHEKI and (b) TANSUISHOKU (a/b = about 0.79) for cyan, TANOHSHOKU for yellow, a mixture of (c) HANA-MARON and (d) SHOENSHI (c/d = about 0.3) for magenta, and TSUYAGURO for black (All pigments were products by Colour Shop KAJITA & Co..) were used. Colour reproduction of the obtained image was highly satisfactory and its resolution and gradation were as good as those in Example 1. Example 3 A permanent co,lour photograph was prepared in the same manner as in Example 2excep-t-that- the heating at -1 10- fo-r 15minutes was carried out for hardening the photosensitive element instead of all the firing processes except the last one The obtained inage was as fine as that in Bxample 2 and was good enough to be appreciated as a photograph. Example 4 A permanent colour photograph was prepared in the same manner as in Example 3 except the followings: heating processes for hardening the photosensitive element were omitted, but a thin film of polyvinyl pyrolidone having a thickness of about 1 E, were prepared among photosensitive layers, then the temperature was raised from the room temperature to about 200 C at an almost constant rate for about 2 hours and 50 minutes, and further fired during 1 hour and 10 minutes to reach about 65O'c. The resultant colour image was as fine as that obtained in Example 3. Example 5 A permanent colour photograph was prepared in the same manner as in Example 3 except that an photosensitive element mainly consisting of polyvinyl para-azide benzoate (FPER manufactured by Fuji Yakuhin Kogyo Co., Ltd.) was used instead of the one mainly consisting of cinnamic acid ester of polyvinyl alcohol. The obtained image was good and satisfactory enough. Industrial Applicability The colour photograph obtained in the present invention does not contain any organic matters in its base plate or in its image so that it can be preserved permanently. Especially the colour of the image does not change or fade as it consists of inorganic materials. Also, since lithographic films are used for colour reproduction, the image has a resolution and gradation as good as those in ordinary photographs. The permanent photograph is, therefore, not on 1 a fine cbject for appreciation but also highly useful as a recording material to be preserved for a long time. It is also highly satisfactory in respect of colour reproduction. Especially when it is a comparatisel- small photograph, its excellent resolution and gradation make it worthy of appreciation and give it a new value. The present invention offers a means which can provide such a valuable permanent photograph as above without using expensive printing equipments. Since this means can produce permanent photograph comparatively easily, the present invention contributes to spread the permanent photograph. According to the present invention, by giving a single firing treatment to the recorded material in multi layers, the information is able to preserve for ever. ln this respect the present invention has a great industrial applicability, providing not only visual image information but also a new multi-dimensional medium for permanently recording the information.

Claims: What is claimed is: 1. A permanent colour photograph having a colour image of inorganic pigments on its base plate, which is characterized by forming said image according to two processes, one of which is to form a colour image by repeating procedures providing a photosensitive element on a base plate consisting at least of an inorganic material and/or metal, exposing said element imagewisely through direct screened and colour separated lithographic film, developing image parts of said element with a toner containing inorganic pigments, and the other of which is, after at least the final image formation procedure, to fire said element on said base plate by heating the whole up to higher than about 400t so as to fire said element away and to fuse the inorganic pigments to said base plate. 2. A permanent colour photograph claimed in Claim 1, which is characterized by using a mixture of KAIHEKI and TANSUISHOKU for cyan colouring, OHSHOKU for yellow colouring, a mixture of MARON and SHOENSHI for magenta colouring and TSUYAGURO for black colouring, which are selected from overglaze colours in ceramic art. 3. A method for producing a permanent colour photograph, which is comprised of (A) a process for forming a colour image by repeating each procedure of (a) providing a photosensitive element on a base plate comprised of an inorganic material and/or metal, (b) exposing said photosensitive element imagewisely through a direct screened and colour separated lithographic film, (c) adjusting the toner acceptability of image parts of said element by exposing the element to solvent vapor which is able to make said element swell, and then (d) developing said element with a toner containing inorganic pigments and removing the excessive toner, and -(B)- at least after -the- -final colour image formation: a process firing the formed image with said base plate by heating the whole up to higher than about 400c. 4. A method for producing a permanent colour photograph claimed in Claim 3, which is characterized by carrying out said firing process in an oxidizing atmosphere and with a heating rate of less than about 4t /minute from the room temperature to about 200t. 5. A method for producing a permanent colour photograph claimed in Claim 3 or in Claim 4, which is characterized by using a thermosetting photosensitive element as the photosensitive element and heating it at about 200t instead of said firing processes except the one carried out after final development. 6. A method for producing a permanent colour photograph claimed in Claim 3 or in Claim 4, which is characterized by providing-between each layer of said element an -intermediate layer which will not be affected by an application of new photosensitive element. 7. A method for producing a permanent colour photograph claimed in Claim 5 or in Claim 6, which is characterized by carrying out said firing process only after the final colour image formation. Claims after amendment under Article 19 (1). What is claimed is: 1. A permanent colour photograph having a colour image of inorganic pigments on its base plate, which is characterized by forming said image according to two processes, one of which is to form a colour image by repeating procedures providing a photosensitive element on a base plate consisting at least of an inorganic material and/or metal selected from silver and copper, exposing said element imagewisely through direct screened and colour separated lithographic film, developing image parts of said element with a toner containing inorganic pigments, and the other of which is, after at least the final image formation procedure, to fire said element on said base plate by heating the whole up to higher than about 400 c so as to fire said element away and to fuse the inorganic pigments to said base plate. 2. A permanent- colour photograph claimed---in Claim 1, which is characterized by using a mixture of KAIHEKI and TANSUISHOKU for cyan colouring, OHSHOKU for yellow colouring, a mixture of MARON and SHOENSHI for magenta colouring and TSUYAGURO for black colouring, which are selected from overglaze colours in ceramic art. 3. A method for producing a permanent colour photograph, which is comprised of (A) a process for forming a colour image by repeating each procedure of (a) providing a photosensitive element on a base plate comprised of an inorganic material and/or metal selected from silver and copper, (b) exposing said photosensitive element imagewisely through a direct screened and colour separated lithographic film, (c) adjusting the toner acceptability of image parts of said element by exposing the element to solvent vapor which is usable to make said element swell, and then (d) devetloping--said element with a toner cr-- --'-ning inorganic pigments and removing the excessive toner, and (B) at least after the final colour image formation, a process firing the formed image with said base plate by heating the whole up to higher than about 400t . 4. A method for producing a permanent colour photograph claimed in Claim 3, which is characterized by carrying out said firing process in an oxidizing atmosphere and with a heating rate of less than about 4t /minute from the room temperature to about 200t. 5. A method for producing a permanent colour photograph claimed in Claim 3, which is characterized by using a thermosetting photosensitive element as the photosensitive element and heating it at about 200t instead of said firing processes except the one carried out after final development. 6. A method for producing a permanent colour photograph claimed in Claim 3, which is characterized by providing between each layer of said element an intermediate layer which will not be affected by an application of new photosensitive element. 7. A method for producing a permanent colour photograph claimed in any Claim of Claim 4 to Claim 6. which is characterized by carrying out said firing process only after the final colour image formation. Brief statement for amendment under Article 19 (1) 1. As for claims 1 and 3, general expression of metal was restricted to " silver and copper" based on the description at 26th#28th line on page 3. The quality and property of permanent photograph obtained in this invention strongly depend on kind of metal used in base plate. Therefore, this amendment is made to remove misunderstanding that this invention is obvious from other techniques concerning other metals. 2. As for claims -57, formal mistake were amended.

Inventors: ARIGA, NAGATOSHI, TOMITA, SEIJI
Applicants: KABUSHIKIKAISHA ARIGA SHASHINKAN
Application year: 1982
Main classification: G03C5
IPC codes: B44C1, G03F7