How did film become a photo?

The development of black-and-white film can be completed in the bright room, so only some equipment and materials are needed:

1. Developing tank for film development. There are mainly two kinds of plastic and stainless steel. From the specification, some can only develop one kind of film, and some can be adjusted to adapt to different films. I use AP brand plastic developing tank, which can develop 1 or 2 rolls of 135/126 film or 1 roll of 127/12/22 film at the same time, and the film rolling is very convenient, and the market price is 16 yuan;

2. There are preferably two plastic measuring cups, one for developing liquid medicine, one for fixing liquid medicine and one for 5 yuan.

3. As long as it is sensitive to the temperature, the thermometer used for measuring the temperature of the liquid medicine can be used. I use a thermometer special for darkroom, and the dial has luminous light. I can't find any for sale in Foshan for the time being. I borrowed this one from Brother Hyenas.

4. Fixed clock can be replaced by ordinary LCD alarm clock;

5. The dark bag used for film loading in the bright room, of course, can be omitted if there is a darkroom, and 35 yuan with a medium market price;

6. I use HB-17 developing concentrate from Le Kai (one bottle from 35 yuan can be used for 2-3 volumes) for developing liquid and fixing liquid, and the fixing liquid is prepared with fixing powder. The specific preparation quantity depends on the instructions and can be reused.

2. Pre-development work

1. Film winding and canning

This process is all carried out in a dark bag. Put all the parts of the developing tank, the film to be developed and scissors into the dark bag first, and then you can start film winding and canning. The film winding action must be slow and even. A roll of 135 film just runs out of one spool. After winding, cut the film with scissors. Before this step, it is best to practice several times with waste film under the bright room, so as not to fail in the formal work.

the film is positioned by the spool track, and the rewinding films are isolated from each other, so as to ensure that the washing liquid can flow freely and evenly between the film gaps:

2. Preparation of the liquid medicine

Preparation of the developing liquid medicine: I used the black and white film of SHD1 from Le Kai, so I chose HB-17 concentrated developer from Le Kai. You can choose different dilution ratios according to the actual situation. Generally, there are instructions on the bottles containing potions. I chose the scheme of 1: 12/24 1/5 minutes and 3 seconds. Because it takes 65ml to develop two rolls of film with AP tank, it can be calculated that it is 5ml concentrated solution +6ml clear water. I use tap water, of course, distilled water can be used if the requirements are high.

preparation of fixing liquid medicine: I used fixing powder. 1 measuring spoons +65ml water. You can make it according to the specific instructions. I would like to remind everyone here that if it is made of fixed powder, it should be evenly added with water, and it will be dissolved while stirring, otherwise it will easily cause the powder to block.

third, the film processing step

after the preparation of the medicine, the film processing can be started, which is also the most critical step.

first measure the temperature of the developer to ensure that the temperature is consistent with the nominal temperature.

At that time, I measured that the room temperature was 23℃, which basically met the requirements of washing. If it was in summer or very cold winter, there would be no problem in the air-conditioned room. If it was not, the temperature of the liquid medicine would have to be adjusted by ice cubes or hot water. When the development temperature is higher than the standard development temperature provided by the film manufacturer, there will be excessive development, the density contrast of the negative film will increase, the particles will become coarse and the fog will increase; If the development temperature is low, it will lead to insufficient development and the negative will become dull and soft. Unless you need to achieve special effects, it is not recommended to violate the requirements of development temperature.

after the temperature is right, you can inject the medicine into the developing tank. There is a water injection hole at the top of the developing tank, and the injection process should be uniform. You can start timing from the moment you inject the potion. Generally, it takes 3-6 seconds to inject all the 65ml potion, and the potion is constantly stirred for one minute after pouring. There is a rotatable stirring rod at the top of AP tank, which can drive the blade shaft to move up and down in the tank. If the tank you use does not have this device, you have to pick up the whole tank and shake it.

then stir for 5-1 seconds every 1 minute until the development is finished. This requirement is to make the liquid medicine fully contact the film and completely complete the development chemical reaction.

since it takes about 3-6 seconds to pour out the potion after the development, it is necessary to start pouring out the potion half a minute before the end.

development temperature is important, but development time is also very important. Because the development time is too long, the density and contrast of the negative film are improved, and the development time is too short, and the negative film will be under-developed. Although modern black-and-white films have a certain tolerance, improper control of temperature and time in the process of developing will still affect the tone and level of the film.

immediately after development, pour clean water into the developing tank, stir it continuously for 1 minute, and then pour the clean water out.

Then, the prepared fixing solution can be poured into the developing tank, continuously stirred for 1 minute, and then stirred every 1 minute. Fixing at 2℃ for about 1 minutes. The temperature is higher, the fixing time is shorter, the temperature is lower, the fixing time is longer, and the requirements are not very strict. At 23℃, the fixing time is 9 minutes.

iv. film washing step

after fixing, it can be washed with water. The purpose is to completely remove the residual liquid medicine on the film so as to preserve the film for a long time. Open the cover of the developing tank, put it under the faucet, connect a hose to the faucet, and insert the other end in the center of the spool. Open the faucet and rinse it with moderate running water for 2-3 minutes.

add one or two drops of detergent as wetting agent to the final clean water at the end of water washing, and the water washing process can be completed after thorough stirring for half a minute. The purpose of this is to eliminate possible water stains on the film.

V. Drying of film

Hang the film in a ventilated and dust-free room, and clip a clip with a certain weight at the lower end of the film to prevent the film from curling during drying. Both sides of the film should be gently wiped off with a soft wet sponge to ensure that the film can be dried quickly and evenly.