The photos are stuck together. How can we separate them without affecting the photos?

1. Pretreatment of contaminated films

Before various types of remedial treatment are carried out on stained negatives and photos, a film hardening treatment should be carried out in advance, because strong acid is sometimes used in the treatment solution, which may cause the danger of melting the film.

formula of film hardening solution

4% formaldehyde (formalin) 1ml

5g anhydrous sodium carbonate

Add water to 1ml

Usage: soak the stained negative or photo in clear water, then soak it in the film hardening solution for three minutes (temperature is 2℃), take it out, then throw it into clear water and rinse it briefly.

ii. treatment of various stains

(1) oxidation pollution

yellow (or yellowish brown) oxidation pollution is mostly caused by oxidation products of the developer. The reasons are: (1) the sodium sulfite in the developer is insufficient; (2) The developer used is too old; (3) insufficient agitation during development; (4) Fixing solution does not have enough acid to neutralize the alkaline developer remaining on the negative or photo.

Therefore, it is possible to prevent the occurrence of this oxidation pollution by neutralizing the alkalinity with an acidic solution before fixing.

There are yellow or yellow-brown stains on the negative film due to oxidation pollution. If it is all, it has no obvious influence on enlargement and printing. If it is partial, it is not suitable for printing. It will make the photos that are released immediately appear uneven patches and should be eliminated.

Yellow oxidation pollution can be eliminated by oxidation and reduction.

potassium permanganate (gray manganese) and potassium dichromate are both strong oxidants. If bromine or chlorine exists under the action of strong acid, the reduced metallic silver can be brominated or chlorinated again, so that the silver shadow still remaining on the film base or paper base can regain its photosensitive function. After oxidation, it can be re-exposed and re-developed, so that the original image can be restored and reproduced, and the original negative film will become yellow in the photo.

potassium permanganate solution formula

2.6g of potassium permanganate in solution A

add water to 5ml of solution B

; Sodium chloride (refined salt) 37.5g

concentrated sulfuric acid (note) 8ml

Add water to 5ml

(note) Concentrated sulfuric acid should be added to the water slowly to avoid boiling and splashing and scalding the skin.

when in use, pour solution A into solution B. This solution can't be stored, and it will become invalid in about half an hour. Pour it out after use.

usage: soak the yellow salted film (or photo) polluted by oxidation in clear water, then harden the film in advance, wash it thoroughly, and then soak the film (or photo) in the above mixed solution for bleaching for about 3 minutes (liquid temperature is 2C). And constantly stirring, when the black silver shadow is oxidized to silver chloride, the image will disappear completely, and then it will be rinsed in flowing clean water for 5 minutes. At this time, the film is stained with manganese dioxide brown, which can be dipped in 2 ~ 5% sodium bisulfite (that is, sodium bisulfite) cleaning solution for about 3 minutes until the brown color disappears completely. This step should be clean and thorough. The more transparent the negative film is, the better the photo is. It is better to take only a little longer than too short, otherwise the manganese dioxide will not be removed completely and a brown image will be formed.

After cleaning, it can be slightly washed with water to remove its acidity, and then it can be exposed to sunlight in the indoor window, so that the restored silver chloride image can be re-sensitized. At this time, the amount of exposure is an important link, until the image gradually appears from light gray to light red, that is, it is developed in D-72 developer (diluted 1:3) for 3-5 minutes (developer with excessive sodium sulfite, such as D-76, is not allowed), and then washed with water, fixed (with F-5) and rinsed thoroughly in clear water, and the yellow oxidation stain is removed. The whole process can be carried out under the white light of darkroom.

(II) Processing of yellowing and fading photos

The yellowing and fading photos are mainly due to poor storage, or sulfide substances remain in the photos, and due to the influence of air and moisture, the photos turn yellow and fade, and the images even fade to light gray. Of course, the above redox method can also be used to restore the image, reproduce it in layers, remove the yellow stains, and then reproduce it again. The shadow level is much better than that of the yellow faded photos and the orange filter. In order to be prudent, it is best to turn over a base plate with an orange filter before re-processing, so as to avoid being unable to save when the processing work is not good.

1. The following bleaching solution formula can be used to restore the yellowed and faded photos:

.5g of potassium permanganate

5ml of concentrated hydrochloric acid

adding water to 2ml

cleaning solution

adding 1g of sodium bisulfite

adding water to 2ml

The film still needs to be hardened in advance, and the following formula can be used:

potassium alum.

note: the damaged photos cannot be polished, otherwise the damaged glue will stick to the polishing plate together with the silver shadow. If the damage is not very serious (that is, the film is not powdery), it can still be polished. If you are stuck on the glazing board, don't tear it off. You can immerse it in clear water together with the glazing board, and it will fall off automatically after soaking.

(3) Sulfur pollution

Most of the causes of yellow sulfur pollution are caused by the disproportionate ratio of acid and sodium sulfite contained in the fixing solution used. Because the acid will decompose sodium thiosulfate, the fixing solution will produce sulfur precipitation, which will cause fine sulfur particles in the fixing solution to precipitate on the negative surface, thus reacting with the film and quickly generating yellow silver sulfide stains. In addition, the same phenomenon will occur when the fixing solution exceeds 3℃. The solution must use enough sodium sulfite to dissolve sulfur particles. The solution containing 1% sodium sulfite can be heated to 38℃, and the film containing yellow sulfur pollution is hardened and then immersed in the rinse, and it is constantly shaken until the yellow silver sulfide stain is completely dissolved, and then it is fully washed with water to remove the sodium thiosulfate contained in the film.

(4) red and green stains

If red and green stains appear after the negative film is developed, most of them are using too old developer, or sodium thiosulfate is mixed in the developer; Then there is too much sodium sulfite in the developer, because sodium sulfite has the function of dissolving the silver plate, thus forming a colloidal silver particle attached to the film.

its phenomenon is that it is red when viewed from light transmission, and green when viewed from reflected light, which is most obvious in the dark part and slightly in the bright part. This kind of dichromatic fog is a kind of silver particle pollution, which can be removed slightly, and can be alleviated seriously. It is difficult to remove it at all and can be rinsed with the following solution.

rinse solution for dichromatic silver stains

25g of sodium sulfite

5g of potassium cyanide (highly toxic)

add water to 5ml

If it is a slight dichromatic fog, it can also be rinsed with diluted thinning solution of equal amount, but it must be turned quickly when working, and washed in flowing clean water as soon as it is removed, otherwise it will cause thinning effect of equal amount.

(5) blue or green stains

Most of the blue or green stains produced by the negative film are not completely cleaned, so it can be removed with a liquid, and then washed thoroughly.

2 ml of glacial acetic acid

1 g of sodium sulfite

add water to 5 ml

(6) blue stain

Sometimes blue spotted stains appear on photos or negatives during the process of developing and printing, which are produced when acidic substances meet iron particles, and can be eliminated by neutralizing the acid with 1% baking soda solution. Or use 1% sodium carbonate solution. A simpler way is to soak the photo in the developer and rinse it for a while, but it must not be fixed, and then wash it with water for a short time. Using a magnetic basin with rust at work is in danger of causing this blue stain.

(7) Gray fog

There are several situations in which gray fog appears in photos. One is that the white light is partially grayed, which means that the paper distribution model is wrong, and the tone is soft and grayed. What we are talking about now is that there is a general phenomenon of fog on the white edge, and there are also two situations: first, it is affected by weak general exposure; The other is the general fog phenomenon in expired photographic paper. The treatment method is as follows: when developing with D-72 and washing at 1: 2, add .8-.1g of commercially available antifogging agent benzhi triazole to every 1ml of solution; If the expired film is developed by D-76, .2-.3 g per 1 ml of liquid can prevent the general fog.

(8) White pollution

Most of the white stains on the negative are caused by calcium, aluminum or alum.

treatment measures: the calcareous stains are caused by hard water, which can be washed with 2% glacial acetic acid solution; It belongs to the stain formed by aluminum sulfite or aluminum hydroxide and alum, and can be cleaned with 1% sodium carbonate solution. This kind of white stain is caused by carelessness in the fixing process, such as putting acetic acid and sodium sulfite upside down when preparing fixing solution, or adding potassium alum when using acidic fixing solution, which will produce organic or aluminum precipitate and stain the negative.

(9) Oil stain pollution

After 1 ml of glacial acetic acid, 6 g of vaseline and 1 ml of carbon tetrachloride are mixed, the oil stain-contaminated film is wetted with breath, then dipped in liquid with chamois or sponge, or gently wiped on both sides with benzene or gasoline, and then wiped with chamois.

(1) Water stains and spots:

The film should be wiped with cotton before drying. If there are any drops after drying, the film can be rinsed in water at 27℃ to eliminate them. Films with serious water stains can be cleaned with 1% sodium carbonate solution.

(11) Moldy spot treatment

The negative film is affected by moisture during storage, which is a kind of protein mold. It can be scrubbed with 1/5 sodium pentachlorophenol solution for 5 minutes, and then washed with water to dry. Special care should be taken when handling, because if the negative film is kept for too long, the adhesion of the emulsion will not be strong and it will easily fall off.