JPS5846008B2 - Decontamination method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for removing yellow to orange-yellow stains that occur when a photographic image is subjected to a reduction process using a photographic reduction liquid containing a ceric compound as a main ingredient.

Reducing power in photographic processing is a method of reducing image density by dissolving and removing metallic silver forming an image or existing as fog as a soluble silver salt. Although power reduction is also performed on images, the present invention deals with the case of metallic silver.

Farmer's reducing agent, which uses potassium ferricyanide and sodium thiosulfate, is well-known as a reducing agent for photography.However, the used solution of Farmer's reducing agent is extremely unstable and cannot withstand storage, and if it is discarded, it becomes a pollutant. It cannot be disposed of because it may liberate.

For this reason, it is hardly used at present.

In addition to Farmer's reducing solution, reducing solutions using dichromates and permanganates are also known, but these are not used for the reasons mentioned above and because they are associated with environmental pollution.

For the above reasons, ferric salts and thiosulfates (Belicki
type) or a reducing solution using a ferric salt of aminopolycarboxylic acid and thiosulfate or thiourea (in color photographic processing, it is called a bleach-fix solution type or BF type).

) is used.

However, Belicki-type and BP-type reducing fluids have a low oxidizing power, so the processing time is long, and they have a softening characteristic in which the power is reduced better when the silver concentration is high than when the silver concentration is low. Therefore, it is not recommended for use in plate making.

For the above reasons, power reducing fluids based on ceric compounds that do not cause environmental pollution, have strong oxidizing power, and have inversely proportional power reducing characteristics are being reconsidered, and this type is gradually becoming mainstream.

However, even with the above-mentioned advantages, reduction fluids based on ceric compounds have drawbacks.

The problem is that the film or print that has been subjected to the reduction treatment becomes yellow or orange-yellow colored and contaminated.

It is particularly noticeable in transparent parts of film, and in white parts of prints.

It is unclear why this contamination occurs or the current treatment, but unlike the case of Farmer's reducing solution, it is not removed even after a long period of water washing.

Contamination can be avoided to some extent if the entire film or print is reduced, but if the pressure is reduced partially, the area to which the reducing fluid is attached will turn yellow to orange-yellow due to the contamination.
Since the film is wrapped, it is not suitable for viewing, and in the case of film and photographic prints, it produces extremely unfavorable results and cannot be used in the production of printing plates.

Furthermore, as mentioned above, this contamination is not removed by washing with water and tends to become more concentrated when dried, so this is even more so.

Continuing research into ways to remove this contamination resulted in the following: dithionite and its alkali metal salts, aqueous hydrogen peroxide, organic and inorganic peroxides or hydrogen peroxide compounds, hydroxylamine and its inorganic or organic acid salts. It has been found that yellow to orange-yellow stains can be removed by treatment with an aqueous solution of hydrazine and its inorganic acid salts, thiourea, ethylene thiourea, mercaptocarboxylic acid and its alkali metal salts, and alkylaminoalkylthiols.

These substances may be used alone or in a mixture of two or more kinds, and it is preferable to use them in an acidic state.

The main substances that are effective in removing pollution are as follows:
Among ring dithionates, sodium dithionite,
Potassium ring dithionate may be used as an organic or inorganic peroxide or hydrogen peroxide addition substance as long as it decomposes or releases hydrogen peroxide in solution. Examples include sodium perborate, peroxide, etc. Examples include sodium oxide, sodium percarbonate, and benzoyl peroxide.

Examples of inorganic or organic acid salts of hydroxylamine include hydroxylamine sulfate, hydroxylamine hydrochloride, and hydroxylamine oxalate; examples of inorganic acid salts of hydrazine include hydrazine sulfate and hydrazine hydrochloride; examples of mercaptocarboxylic acids include thioglycolic acid and thiomalic acid. , mercaptopropionic acid, mercaptobutyric acid, etc. Examples of the alkylaminoalkylthiols include mercaptoethylamine, diethylaminoethanethiol, dimethylaminopropanethiol, and the like.

Since a solution containing only the above-mentioned contamination-removing substance becomes cloudy after treatment, the occurrence of cloudiness can be prevented by adding tartaric acid, aminopolycarboxylic acid, pyrophosphoric acid, and polymerized phosphoric acid to the solution.

Naturally, these anti-turbidity substances have similar effects even if they are alkali metal or ammonium salts, and they may be used alone or in combination.

The most typical aminopolycarboxylic acid is ethylenediaminetetraacetic acid (EDTA), but others include cyclohexanediaminetetraacetic acid, dihydroxyethylglycine, diethylenetriaminepentaacetic acid, diaminopropanoltetraacetic acid, hydroxyethylethylenediaminetriacetic acid, and glycol ether diamine. Examples include tetraacetic acid nitrilotriacetic acid, metaphenylenediaminetetraacetic acid, and the like, and their alkali metal or ammonium salts can also be used in the same manner.

The decontamination liquid may be used immediately after the decontamination treatment is performed using the decontamination liquid, or after rinsing or washing with water after the decontamination treatment.

After that, it may be washed with water and dried.

This makes it possible to obtain films and prints free from yellow to orange-yellow stains.

This will be explained in detail below using examples.

Example 1 Fujiris orthofilm, type V, (VO-100
) was used to expose the image through a contact screen, and then the halftone image obtained using Lith-sensitive material developer D-85 and fixer F-6 was treated with the following ceric compound reducing solution and stain removal solution. I did it.

For processing, the halftone image that had been thoroughly washed with water was processed with a ceric compound reducing solution for 30 seconds at 20°C, and (A) 20
Rinse with water for 5 minutes at °C and dry immediately.

(B) Immerse in decontamination solution immediately after reducing force.

The time was 30 seconds at 20°C, followed by washing with water and drying.

(C) After power reduction treatment, rinse treatment for 30 seconds at 20°C, then treatment with decontamination solution, washing with water, and drying.

0 Washed and dried without any reduction treatment.

As a result of the above processing, the transparent part in (4) took on a yellow color, whereas in (B) and (C), it was colorless and transparent, as in (2), and the effect was It was very clear.

Also, using Fuji phototypesetting paper Wp (PL-3owp),
After printing (exposure) with a phototypesetting machine, use D-72 developer and F-6
The character images obtained using the fixer were processed in the same manner as described above.

The result was that in (4) the white background appeared yellow, whereas in (B) and (C) it was almost colorless, the same as in (D), and the effect was extremely clear. there were.

Regarding the above-mentioned substances, the same materials as in Example 1 were treated by the same method, and as a result, the same contamination removal effect as in Example 1 was obtained for all the above-mentioned substances.

That is, in processing method (4), the transparent part of the film and the white part of the phototypesetting print turned yellow, whereas in the processing method (BXC), the transparent part of the film and the white part of the phototypesetting print turned yellow. The white background portion of the phototypesetting print was colorless, which was the same as the treatment method (D), and the stain removal effect was extremely clear.

The decontamination solution became slightly warm after being left for a while.

As a result of the treatment in the same manner as in Example 1, when no decontamination solution was applied, it turned yellow, whereas when treated with decontamination solution, it was colorless, and the effect was very clear. Ta.

In addition, EDTA disodium and tartaric acid EDT are included in the decontamination solution.
A: Those that did not contain ammonium, sodium hexametaphosphate, and sodium pyrophosphate exhibited a slight temperature after treatment, whereas those containing them remained transparent and showed no turbidity even after being left standing. .

Claims (1)

[Scope of Claims] 1. A photographic reducing solution containing a ceric compound as a main ingredient is used to reduce the power of the image, and the resulting image is treated with dithionite and its alkali metal salts, hydrogen peroxide, and organic and inorganic peroxide. one or two types of hydrogen peroxide adducts, hydroxylamine and its inorganic or organic acid salts, hydrazine and its inorganic acid salts, thiourea, ethylenethiourea, mercaptocarboxylic acids and their alkali metal salts, and alkylaminoalkylthiols. A contamination removal method characterized by treatment with a solution containing the above. 2 Tartaric acid and its alkali metal or ammonium salts,
It is characterized by treatment with a solution additionally containing one or more of aminopolycarboxylic acid and its alkali metal or ammonium salt, pyrophosphoric acid and its alkali metal or ammonium salt, and polymerized phosphoric acid and its alkali metal or ammonium salt. A method for removing contamination according to claim 1.