How to deal with dyed negatives and photos 1 Pretreatment of dyed film Before various types of remedial treatment are carried out on dyed negatives and photos, the film should be hardened in advance, because strong acid is sometimes used in the treatment solution, which will cause the danger of film melting. Formula of film hardening solution Formaldehyde 40% (formalin) 10 ml anhydrous sodium carbonate 5 g water to 1000 ml Usage: soak the dyed film or photo in clear water, then soak it in film hardening solution for three minutes (temperature 20℃), take it out and rinse it briefly with clear water, then soak it in fresh F-5 acid film hardening solution for five minutes, and then wash it thoroughly. Second, the treatment of various stains (a) oxidation pollution Yellow (or yellowish brown) oxidation pollution is mostly caused by the 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 stirring during development; (4) Fixing solution does not have enough acid to neutralize the alkaline developer remaining on the negative or photo. Therefore, after development and before fixing, such oxidation pollution can be prevented by neutralizing alkalinity with acidic solution. Oxidation pollution has yellow or tan stains on the negative. If it is all, it has no obvious influence on enlargement and printing. If it is local, it is not suitable for printing. It will make the photos released immediately appear uneven patches and should be eliminated. Oxidation-reduction method can eliminate yellow oxidation pollution. Potassium permanganate (gray manganese) and potassium dichromate are 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. As long as it is exposed and developed again after oxidation, the original image can be restored and copied again, and the original yellow stains left on the negative can be obtained. 2.6 grams of potassium permanganate solution A was added to 500 ml of solution B together with water; Sodium chloride (refined salt) 37.5 g concentrated sulfuric acid (note) 8 ml water to 500 ml (note) concentrated sulfuric acid should be slowly added to the water to avoid boiling and splashing and scalding the skin. When in use, pour solution A into solution B, which can't be stored and will be invalid in about half an hour. Dump it after use. Usage: soak the oxidized yellow salt film (or photo) in clear water, then harden the film in advance, wash it, and then soak the film (or photo) in the above mixed solution for bleaching for about 3 minutes (liquid temperature is 20C). And constantly stirring, when the black silver shadow is oxidized into silver chloride, the image will disappear completely, and then rinse in flowing clean water for 5 minutes. At this time, the film is dyed brown by manganese dioxide, and it can be soaked in 2 ~ 5% 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, the better the photo. It is best to take only a little longer, not too short, otherwise manganese dioxide can not be completely removed, and a brown image will be formed. After cleaning, it can be slightly rinsed with clear water to remove its acidity, and then exposed to sunlight in the indoor window, so that the restored silver chloride image can be re-sensitized. At this time, the exposure is an important link, until the image gradually changes from light gray to light red, that is, it is re-developed in D-72 developer (diluted with 1:3) for 3-5 minutes (excessive sodium sulfite developer, such as D-76, is not allowed), then washed with water, fixed (with F-5), and washed thoroughly with clear water, showing yellow oxidation. The whole process can be carried out in a darkroom with white light. (II) Handling of yellowed and faded photos The yellowed and faded photos are mainly due to poor preservation, or sulfide substances remain in the photos. In addition, due to the influence of air and moisture, the photos turn yellow and fade, and the images even fade to light gray. Of course, you can also use the above redox method to restore the image, reproduce it in layers, remove the yellow stains and reproduce it again. Shadow levels are much better than yellow faded photos and orange filters. In order to be prudent, it is best to turn over a bottom plate with an orange filter before reprocessing, so as to avoid being unable to save it when the processing work is not good. 1. The following bleaching solution formula can be used to restore yellowed and faded photos: potassium permanganate 0.5g concentrated hydrochloric acid 5ml water to 200ml cleaning solution sodium bisulfite 10g water to 200ml, and pre-hardening is needed. The following formula can be used: potassium alum 10g water to 200ml 2. The processing steps are the same as above. Note: Broken photos cannot be polished, otherwise the broken colloid will stick to the polishing plate together with the silver shadow. If the damage is not serious (that is, the film is not powdery), it can still be polished. If it sticks to the glazing, don't tear it off. It can be soaked in clear water with glazed board, and will automatically fall off 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 decomposes sodium thiosulfate, the fixing solution will produce sulfur precipitation, so that the fine sulfur particles in the fixing solution will precipitate on the surface of the negative film, which will react with the film and quickly generate yellow silver sulfide spots. In addition, the same phenomenon will occur when the fixing solution exceeds 30℃. The solution must use enough sodium sulfite to dissolve sulfur particles. The film can be heated to 38℃ with sodium sulfite solution containing 10%, so that the film contaminated with yellow sulfur can be hardened and then immersed in rinsing, and shaken continuously until the yellow silver sulfide stain is completely dissolved, and then fully rinsed with water to remove the sodium thiosulfate contained in the film. (4) After developing the negative film with red and green spots, if there are red and green spots, most of them are used developer or mixed with sodium thiosulfate. Then there is too much sodium sulfite in the developer, because sodium sulfite can dissolve silver flakes, thus forming colloidal silver particles attached to the film. Its phenomenon is that it is red from the perspective of light transmission and green from the perspective of reflected light, which is most obvious in the dark and slightly obvious in the strong light. This two-color fog is a kind of silver particle pollution, which can be removed slightly and alleviated seriously. It is difficult to remove and can be washed with the following solution. Two-color silver dyeing rinse solution: 25g sodium sulfite, 5g potassium cyanide (highly toxic) and 500ml water. If it is a slight two-color fog, it can also be washed with diluted equivalent dilution solution, but the action must be fast when working. Once taken out, it should be washed in flowing clean water immediately, otherwise it will cause equivalent dilution effect. (5) Blue or green stains The blue or green stains produced by the negative film are mostly due to the fact that the anti-halo film on the back of the negative film has not been thoroughly cleaned, so it can be removed with liquid and then thoroughly cleaned. Adding water to 500ml (VI) of sodium sulfite 10g of glacial acetic acid sometimes leads to blue stains during the development and printing of photos or negatives, which are produced when acidic substances meet iron particles, and can be eliminated by neutralizing the acid with 10% baking soda solution. Or 10% sodium carbonate solution can be used. A relatively simple method is to soak the photos in developer and rinse them for a while, but they must not be fixed, and then rinse them with clear water for a while. Using rusty magnetic pots at work is in danger of causing this blue stain. (7) There are several situations in which fog appears in fog photos. One is that the white light turns gray, indicating that the paper distribution model is wrong and the tone is soft and gray. What we are talking about now is the common phenomenon of fog on white edges, and there are also two situations: first, it is affected by weak general exposure; The other is the common fogging phenomenon of expired photographic paper. The treatment method is as follows: when D-72 is used to develop color 1: 2, 0.08-0. 1g of commercially available antifogging agent benzotriazole is added to every 1000ml solution; If the expired film is developed with D-76, 0.02-0.03 g can be added to every 1000 ml of liquid to prevent fogging all over the body. (8) Most of the white spots on the white polluted film are caused by calcium, aluminum or alum. Treatment measures: Calcium stain is 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 10% sodium carbonate solution. This kind of white stain is caused by carelessness in the process of fixing solution production. For example, acetic acid and sodium sulfite are put upside down when fixing solution is prepared, or potassium alum is added when acid fixing solution is used, which will produce precipitation of organic matter or aluminum and stain the negative film. (9) For oil pollution, glacial acetic acid 1 ml, vaseline 6 g and carbon tetrachloride 100 ml can be mixed, and then the oil pollution film is wetted by breathing, and then dipped with suede or sponge, or gently wiped on both sides with benzene or gasoline, and then wiped with suede. (10) Water stains and spots: wipe the film with cotton before drying. If there are water droplets after drying, the film can be washed in water at 27℃ to eliminate the water droplets. The film with serious water damage can be cleaned with 10% sodium carbonate solution. (1 1) During storage, the film treated with mildew spots will produce mildew spots due to the influence of moisture, which is a protein mold. It can be scrubbed with 1/5000 sodium pentachlorophenol solution for 5 minutes, then rinsed with water and dried. Special care should be taken when handling, because if the film is kept for too long, the adhesion of the emulsion is not strong and it is easy to fall off.