Title of Invention	AN IMPROVED COLOUR REVERSAL PROCESS FOR PRODUCING COLOUR PRINTS
Abstract	This improved color reversal process for producing color prints from adiposities consists of sequential treatment of the exposed film with a first developed a color developer and a bleach and fix composition. By this process color reversal prints can be obtained directly without the formation of internegatives.

Full Text

This invention relates to an improved colour reversal process for producing colour prints. This indegenously developed technology, is particularly,but not exclusively applicable in generating colour prints from colour diapositive films/slides without the step of preparing internegatives therefrom. This process finds direct application in developing satellite/aerial diapositive images produced in film recorders using a white light source. The improved process avoids the intermediate stage of internegative formation which not only simplifies the operation, but also avoids quality deterioration of prints. Commercially, the improved process is applicable in producing colour prints from 35 mm slides. The colour reversal process of the subject invention is carried out in three sequential processing steps using three different compositions for developing and fixing. These compositions are herein after termed as : (a) First developer (b) colour developer and (c) Bleach and Fixer composition. The above compositions are prepared by admixing _■■,. _i * t i i i ■ T my n * i» i l.. . _ *. i. . ^ i i i i H w M i nj i i K _i_ 1/ -~4 \f x i _i_ -« I_I i_ *~>. •_" ' ' 'r* ili i L* iS. A. *i . i 1 1 *!* L L i.T: '_ ' 1 *7* w *T* .'- ' ' ' ' *"* ' ' ' *"• *~* ' - ' r" composition described herein under. The range of individual chemical compounds are stated thereagainst. A. Frist. developer: (Quantity in gms) 1. Sodium Hexameta Phosphate 1-2.5 (Calgon') 2. Anhydrous Sodium Sulphate 27 - 35 3. Hydroquinone 10 - 20 4. Anhydrous Sodium Carbonate 27 - 35 5. 1-Phyny1-3-pyrozolidone 0.09 - 0.11 (* Phenidone') R Potassium Bromide 3 'i 7. Sodium Thiocyanate 0.5 to 1.5 The above quoted chemicals are admixed to prepare one litre of aqueous solution. The second composition used in the improved process is the colour developer and has the following chemical compounds dissolved in one lilre of water. B. Colour developer: (Quantity in gms) 1., Sodium Hexameta Phosphate 0.5 - 2.5 ( Caigon ) 2. Hydroxyiamine sulphate 3.1 -3.8 3. Anhydrous Sodium Sulphite 2-4 4. Anhydrous Sodium Carbonate 30 - 35 5. Potassium Bromide 0.2 to 0.6 6. Benzyl Alcohol (50%) in ml 25 - 35 7. N-Ethyl-(B hydroxyethyl)-3-methyl P-phenyline diamine sulphate 3.8 - 5 The third composition is used as a bleach and fix reagent and has the following chemicals dissolved to make one litre of aqueous solution. c. Bleach and Fixer; (Quantity in gms) 1. NaFe3 EDTA (Sodium Ferric 35 - 65 ethyline diamine tetra acetic acid) 2- Ethylene Diamine Tetra Acetic Acid (EDTA) 5-8 3. Potassium Iodide 0. 9-2 4. Ammonia solution Sp.gravity 0.91 (in ml. ) 10-25 5. Ammonium Thiosulphate 100 - 200 6. Anhydrous sodium sulphate 7-12 7. Potassium Thiocynate 1-2 8. Acetic Acid (Glacial) in ml. 10 - 20 The colour reversal process according to this invention is carried out in three sequential steps. The first step involves treatment of the exposed film with the first developer composition. During this process step, the exposed silver halides in each of the emulsion layers are converted into metallic silver. The chemical reaction involved in the conversion of silver halides to metallic silver in this stage is given herein under. The most critical step in the process of the subject invention is the treatment of the film with the first developer as it decides the colour balance Dmax and Drain. Another significant improvement: is that no dye formation occurs at this stage. The film is then taken out, washed and subjected to the next stage of development by treating the same with the colour developer. During this step, the remaining undeveloped silver halide grains of each of the emulsion layer is reduced to positive silver. Colour developing agent in the composition dyes and colours each sensitised area or layer in hues of red, green and blue. The chemical reaction taking place in this second stage of processing is given below: The film exposed to the colour developer for a period of 3 to 4 minutes is taken out and washed and is then treated with the bleach and fixer composition. Bleaching and fixing actions are combined when reversal papers are used to produce prints. Silver is converted into silver halide by the bleaching component through rehalogenation. The silver halide is then removed by the fixing components in the composition. After a period of 3 to 4 minutes, the prints are taken out, washed, and dried. • ' •'• This invention therefore relates to an improved colour reversal process for producing colour prints directly from diapositives without the formation of internegatives said process comprising the steps of treating exposed films or slides sequentially with (a) a first developer, (b) a colour developer and (c) a bleach and fixer composition, wherein the first developer consists of : 1. Scdiura Hexameta Phosphate 1 - 2.5 gms ( 'Calgon' ) 2. Anhydrous Sodium Sulphate 27 - 35 " 3. Hydroquinone 10 - 20 " 4. Anhydrous Sodium Carbonate 27 - 35 " 5. l-Phynyl-3-pyrozolidone 0.09-0.11" ( A Phenidone' ) 6. Potassium & Bromide 3-4 " 7. Sodium Thiocyanate 0.5-1.5 " dissolved in one litre of distilled water; the colour developer consists of: 1. Sodium Hexameta Phosphate 0.5 - 2.5 gms. ('Calgon') 2. Hydroxylamine sulphate 3.1-3.8 " 3. Anhydrous Sodium Sulphite 2-4 " 4. Anhydrous Sodium Carbonate 30 - 35 " .5. Potassium Bromide 0.2 to 0.6 " 6. Benzyl Alcohol (50%) in ml 25 - 35 M 7. N-Ethyl-(B hydroxyethyl)-3-methyl P-phenyline diamine sulphate 3.8—5 " dissolved in one litre of distilled water, and the bleach and fixer composition consists of: 1. NaFe3 EDTA (Sodium Ferric 35-65 gms ethyline diamine tetra acetic acid) 2. Ethylene Diamine Tetra Acetic Acid (EDTA) 5-8 3. Potassium Iodide 0.9-2 " 4. Ammonia solution Sp.gravity 0.91 (in ml.) 10-25 " 5. Ammonium Thiosulphate 100-200" 6. Anhydrous sodium sulphate 7-12 M 7. Potassium Thiocynate 1-2 " 8. Acetic Acid (Glacial) in ml. 10 - 20 M dissolved in one litre of distilled water. * WE CLAIM : 1. An improved colour reversal process for producing colour prints directly from diapositives without the formation of internegatives said process comprising the steps of treating exposed films or slides sequentially with (a) a first developer, (b) a colour developer and (c) a bleach and fixer composition, wherein the first developer consists of : 1. Sodium Hexameta Phosphate 1 -2.5 gms ( Saigon' ) 2. Anhydrous Sodium Sulphate 27 - 35 3. Hydroquinone 10-20 " 4. Anhydrous Sodium Carbonate 27 - 35 " 5. l-Phynyl-3-pyrozolidone 0.09-0.11" ('Phenidone') 6. Potassium & Bromide 3-4 M 7. Sodium Thiocyanate 0.5-1.5 " dissolved in one litre of distilled water; the colour developer consists of: 1. Sodium Hexameta Phosphate 0.5 - 2.5 gms. ('Calgon') 2. Hydroxylamine sulphate 3.1 - 3.8 " 3. Anhydrous Sodium Sulphite 2-4 " 4. Anhydrous Sodium Carbonate 30 - 35 " 5. Potassium Bromide 0.2 to 0.6 M 6. Benzyl Alcohol (50%) in ml 25 - 35 7. N-Ethyl-(B hydroxyethyl)-3-methyl P-phenyline diamine sulphate 3.8-5 dissolved in one litre of distilled water, and the bleach and fixer composition consists of: 1. NaFe3 EDTA (Sodium Ferric 35-65 gms ethyline diamine tetra acetic acid) 2. Ethylene Diamine Tetra Acetic Acid (EDTA) 5-8 3. Potassium Iodide 0.9-2 " 4. Ammonia solution Sp.gravity 0.91 (in ml.) 10-2 5 " 5. Ammonium Thiosulphate 100-200" 6. Anhydrous sodium sulphate 7 - 12 " 7. Potassium Thiocynate 1-2 " 8. Acetic Acid (Glacial) in ml. 10 - 20 " dissolved in one litre of distilled water. 2. The process as claimed in claim 1, wherein the film is washed free of contaminants after each of the sequential step in a known manner. 3. The process as claimed in any of the above claims, wherein the film is exposed to the first developer for a period of 1 to 2 minutes at a temperature range of 35 to 4 0°C. 4 . The process as claimed in any of the above claims, wherein the film is exposed to the colour developer for a period of 3 to 4 minutes at a temperature range of 37.5 to 39°C. 5. The process as claimed in any of the above claims, wherein the film is exposed to the bleach and fixer composition for 3 to 4 minutes at a temperature range of 30 to 39 °C. 6. The process as claimed in claim 1, wherein the first developer, the colour developer and the bleach and fixer compositions have specific gravity ranging from 1.054 to 1.062; 1.030 to 1.038 and 1.095 to 1.105 respectively at 27 °C. 7. The process as claimed in any of the above claims, wherein the first developer, the colour developer, and the bleach and fixer composition have pH ranging from 9.8 to 10.2; 10.1 to 10.4 and 5.5 to 6.0 respectively at 25 °C. 8. An improved colour reversal process for producing colour prints, substantially as herein described.

Documents:

566-mas-95 abstract.pdf

566-mas-95 claims.pdf

566-mas-95 correspondence-others.pdf

566-mas-95 correspondence-po.pdf

566-mas-95 description (complete).pdf

566-mas-95 form-1.pdf

566-mas-95 form-26.pdf