Radiation imagery chemistry: process – composition – or product th – Post imaging processing – Stabilizing
Reexamination Certificate
2000-08-18
2001-09-04
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Post imaging processing
Stabilizing
C430S432000, C430S463000, C430S933000
Reexamination Certificate
active
06284444
ABSTRACT:
FIELD OF THE INVENTION
This invention relates to the processing of photographic materials and to a processing system therefor.
BACKGROUND OF THE INVENTION
In the processing of photographic materials such as paper and film it has sometimes been found that a stain appears in the developed material. The staining is due primarily to retained sensitising dye. The risk of a staining is greater in the case of rapid processes which have been developed employing short cycle times and in which the durations of the individual stages of development, bleach-fix and wash are correspondingly short.
PROBLEM TO BE SOLVED BY THE INVENTION
Certain chemical compounds, known in the art as stain reducing agents, have been previously used for reducing staining and it has been proposed to add a stain reducing agent to the developer liquid. However it has been found that when a short wash time is employed, for example about 15 seconds, that a stain is produced on the developed material. The inventor of the present invention has found that when the concentration of stain reducing agent in the developer solution is increased, the stain is initially reduced but after about 4 weeks is found to increase substantially. Furthermore, they have found that stain reducing agents are not very soluble in the developer solution and tend to precipitate. The stain reducing agent can be added to the bleach-fix solution with the effect that the stain is reduced but here the stain reducing agent is even more prone to precipitate than in the developer. If the stain reducing agent is added to wash water or stabiliser-replenisher it is soluble to a high degree and prevents stain initially but is present in the entire wash and thus retained in the photographic material.
A solution to this problem has now been invented in which the stain reducing agent is added to the first wash or stabiliser tank only and not to subsequent wash or stabiliser tanks. Stain reducing agent is more soluble in this solution than in the developer or bleach-fix and hence the amount in solution is enough to prevent staining. In a preferred embodiment of the invention the wash or stabiliser tanks are run at elevated temperature sufficient to remove the stain reducing agent from the photographic material.
SUMMARY OF THE INVENTION
According to the present invention there is provided a process for the processing of an imagewise exposed photographic material which has been subjected to development and bleach-fixing which process comprises a plurality of sequential washing steps and where a stain reducing agent is employed wherein the photographic material is contacted with an effective amount of the stain reducing agent in the wash liquid in a first washing step and the photographic material is subjected to a following washing step to remove the stain reducing agent.
ADVANTAGEOUS EFFECT OF THE INVENTION
The advantage of the invention is that staining is kept to a low level.
REFERENCES:
patent: 5006456 (1991-04-01), Morigaki et al.
patent: 5009983 (1991-04-01), Abe
patent: 5236804 (1993-08-01), Tanaka et al.
patent: 6174658 (2001-01-01), Yamazaki
patent: 549175 (1973-06-01), None
Eastman Kodak Company
Le Hoa Van
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