Radiation imagery chemistry: process – composition – or product th – Post imaging processing – Using web or gel
Reexamination Certificate
2001-05-10
2002-11-12
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Post imaging processing
Using web or gel
C430S373000, C430S413000
Reexamination Certificate
active
06479223
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method of producing a photographic image. More particularly, the invention involves the photographic processing of silver halide materials. It applies particularly to processes which do not include washing stages which remove materials from the imaging layers. It is particularly useful for chromogenic colour development where the developer must not be allowed to remain in the image.
BACKGROUND OF THE INVENTION
Processing of photographic materials in automatic processing equipment is normally carried out using tanks of solution through which the processed material is passed. The solutions are modified as they carry out the chemical processes. The effects of this modification are compensated for by replenishment of the tanks with replenisher solutions which add chemicals that have been used during processing. Care has to be taken to replenish tank solutions accurately so that the chemical concentrations are maintained at a constant level so that consistent performance can be ensured.
Solution is lost from the tanks when the processed material leaves the tank. Also, replenisher solutions are added to the tanks in larger quantities than are removed with the processed material thus producing liquid effluent. The solution removed from the tank by over-flow and by being carried out by the processed material allows the removal of chemicals introduced by the chemical processes occurring during processing.
Single-use processing systems involving the use of small volumes of solution have been described ( Research Disclosure September 1997 p638 ). These can involve the application of solutions to the surface of materials in a way which results in a uniform amount of solution being applied. The uniform application of developer to the surface of colour negative paper using ink-jet methods has been described in EP A 94201050.5. U.S. Pat. No. 3,869,288 describes the separate application of developer solution components by spraying droplets. U.S. Pat. No. No. 5,200,302 describes a method of processing involving coating developer to produce a film of processing solution of thickness “at most 20x” that of the dry gel thickness. Uniform application results in low density areas being treated with the same chemical amounts as maximum density areas. This results in inefficient chemical use and possibly in the production of higher than required density in minimum density areas.
U.S. Pat. No. 5,121,131 describes the use of an ink-jet writer to lay down a solution of bleach in an image-wise manner on a material with a uniform, silver-containing layer to produce an image in silver after the bleaching action of the solution has taken effect.
The use of the image information to control the amount of solution applied so that it is applied in an image-wise manner has also been described in U.S. Pat. No.5,701,541 for high silver papers. Processing involves bleaching and fixing to remove silver and silver halide followed by washing to remove all the soluble chemicals left in the coating including developing agent from the developer solution and the dissolved silver halide.
Removal of any material including developer, which will cause the image to be modified on keeping is necessary and a suitable treatment is therefore required. Removal of chemicals is usually performed by a washing stage involving the use of multiple tanks containing water or stabilising solution. These are often replenished by clean water or solutions added to the last of the sequence of tanks with overflow from the last tank replenishing the previous tank and so on until overflow emerges from the first wash/stabiliser tank. In this way, effluent is reduced but the effluent from the wash stage usually forms the majority of the liquid effluent from the process.
Low silver materials have been described which use small fractions of the amount of silver needed to provide the oxidation of developer resulting from development of the silver halide crystals when that oxidised developer is used to provide the image dye in sufficient amount for high image densities via reaction with colour-forming couplers. These low silver materials are processed in the presence of oxidising agents such as hydrogen peroxide in development amplification processes commonly referred to as Redox Amplification or RX processes. In such processes the developed silver image is used to catalyse in an image-wise manner, the production of oxidised developer and hence image dye. Such materials are appropriate for print production.
These were described in combination with the ink-jet application of developer in EP A 94201050.5. The amounts of silver coated in papers processed with RX solutions can be so low that silver can be left in the images without serious loss of quality.
The amounts of silver can also be sufficiently low to allow the retention of undissolved silver halide though it may be necessary to take steps to prevent the production of photolytic silver as described in U.S. Pat. No. 5,246,822 and U.S. Pat. No. 5,441,853.
U.S. Pat. No. 4,469,780 describes image production without washing by developing silver halide material, intensifying and treating with dilute acid-to-neutral buffer solution. Intensification with hydrogen peroxide or other oxidants is used to produce the image and no bleach or fix stages are present to remove silver or silver halide. The minimum image densities after processing are used as the criteria for the effectiveness of the post-development stages.
Colour developer can be removed by chemical treatment as described in a co-pending simultaneously filed patent application by the present applicant or by lamination with a cover sheet containing carbon as described in PCT GB99/04319. In addition, silver or silver halide can be removed by processes enabled by laminating the imaging material with a cover sheet.
It is very desirable to provide as simple and rapid a process as possible and one which requires a simple processing machine with minimal maintenance and which produces little or no effluent. Single-use processing can be used to avoid replenishment but uniform application of processing solutions results in wastage of chemicals because high levels of developer solution are applied whether image density is required or not. The higher than necessary levels of developer provide not only greater difficulty removing the developer but the excess developer produces higher than desired densities in low density image areas.
Normally, removal of unused developer by washing stages is performed and is effective but this produces liquid effluent. The other methods of extraction or destruction of developer are more limited in capacity. It is desirable to minimise the amount of material used to perform the function of extraction or destruction. When developer is applied uniformly, the amounts needed to be removed from the areas of minimum density (Dmin areas) are high. In particular, if methods such as lamination with carbon or the application of chemical treatments are used, the difficulty of removal is greatest where the largest amounts of developer exist. Further, the areas where this occurs are precisely those areas where the problems caused by any density increase are of greatest impact, namely in Dmin areas.
The use of RX processing can allow the retention of silver and silver halide in the image if coated silver levels are sufficiently low. This greatly simplifies the process cycle. However, the avoidance of stages, after development, used for the purposes of silver and silver halide removal, eliminates the opportunity for removal of developer from the coating during these stages, in particular from the low density areas. The problem of removal of developer components from Dmin areas is therefore more serious when these silver-removal stages are eliminated.
The problem to be solved therefore is to provide a process cycle involving a development stage and a subsequent treatment which produces much less liquid effluent than a multi-tank counter-current wash/stabiliser stage. Preferably, no effluent is pro
Evans Gareth B.
Fyson John R.
Hewitson Peter
Kapecki Jon A.
Eastman Kodak Company
Le Hoa Van
LandOfFree
Method of producing a photographic image does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method of producing a photographic image, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method of producing a photographic image will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2987144