Radiation imagery chemistry: process – composition – or product th – Silver halide colloid tanning process – composition – or product
Patent
1994-01-11
1996-05-21
Baxter, Janet C.
Radiation imagery chemistry: process, composition, or product th
Silver halide colloid tanning process, composition, or product
430598, G03C 106
Patent
active
055188621
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a silver halide photographic material providing a negative image with a remarkably hard gradation, a high sensitive negative image, and a good dot image quality, or a silver halide photographic material for forming a direct positive photographic image, specifically to a photographic material containing a novel compound as a nucleus forming agent for silver halide.
TECHNICAL BACKGROUND
The addition of a hydrazine compound to a silver halide photographic emulsion or a developing solution is known in U.S. Pat. Nos. 3,730,727 (the developing solution in which ascorbic acid and hydrazine are combined), 3,227,552 (hydrazine is used as an auxiliary developing agent for obtaining a direct positive color image), 3,386,831 (.beta.-monophenylhydrazide of aliphatic carboxylic acid is contained as a stabilizer for a silver halide light-sensitive material), and 2,419,975, and The Theory of Photographic Process written by Mees, the third edition (1966 ), p. 281.
Among them, it is disclosed particularly in U.S. Pat. No. 2,419,975 that a hydrazine compound is added to obtain a negative image with a hard gradation.
It is described in the same patent specification that the addition of the hydrazine compound to a silver bromochloride emulsion and a development in a developing solution having as high pH as 12.8 provide a very hard gradation photographic characteristic with gamma (.gamma.) exceeding 10. However, the strong base developing solution having pH close to 13 is susceptible to an air oxidation and is instable. Accordingly, it can not endure storing and use for a long time.
An ultra high gradation photographic characteristic with gamma exceeding 10 is very useful for the photo-graphic reproduction of a continuous image with a dot image useful for a printing plate making or the reproduction of a line drawing either in a negative image or a positive image. There has so far generally been used for such the purpose, the method in which a silver bromochloride emulsion having a silver chloride content exceeding 50 mole% preferably 75 mole% is used to carry out a development in a hydroquinone developing solution having the effective concentration of a sulfurous acid ion set at a very low level (usually 0.1 mole/liter or less). However, because of the low sulfurous acid ion concentration in the developing solution in this method, the developing solution is very unstable and can not endure a storing exceeding three days.
Further, since these methods require to use the silver bromochloride emulsion having the relatively high silver chloride content, a high sensitivity has not been able to obtain. Accordingly, it has strongly been desired to use a high sensitive emulsion and a stable developing solution to obtain a ultrahard gradation photographic characteristic useful for the reproduction of a halftone dot image and a line drawing.
In U.S. Pat. Nos. 4,224,401, 4,168,977, 4,243,739, 4,272,614, and 4,323,643, the silver halide emulsions providing the very hard gradation negative photographic characteristics with a stable developing solution are disclosed. However, it has been known that the acylhydrazine compounds used therein have several defects.
That is, it is known that these conventional hydrazines generate a nitrogen gas during a development processing, and these gases are concentrated in a film to form bubbles and damage a photographic image. Further, they are eluted in a development processing solution to exert an adverse affect to a photographic material.
It has so far been known as the means for preventing the elution to the development processing solution to increase the molecular weight of a nucleus forming agent to provide it with an anti-diffusion character. However, it has come to be known that the problem on an aging stability is involved in a conventional anti-diffusible nucleus forming agent. That is, the aging of a coating solution containing the nucleus forming agent generates a deposit in the coating solution to deteriorate a filtering performance and furthe
REFERENCES:
patent: 4767692 (1988-08-01), Inagaki et al.
patent: 4798780 (1989-01-01), Hall et al.
patent: 5155015 (1992-10-01), Jimbo
Baxter Janet C.
Fuji Photo Film Co. , Ltd.
LandOfFree
Silver halide photographic material does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silver halide photographic material, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silver halide photographic material will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2036964