BLEACHING = LIGHTENING
BLEACHING is a process of using chemicals to change a photograph or negative from a dense/dark state to a lighter state.
This image has clearly been bleached to have these lighter tones throughout it. Colour, when bleached, changes somewhat as the darker pigments are leached out.
You need to soak your picture (or negative) in water for 5 minutes to soften it. You can do this while you mix the chemicals.
If you make your own bleaching solution I recommend the following chemical combinations:
64 grams of POTASSIUM FERRICYANIDE
30 grams POTASSIUM BROMIDE
Mix both with 250 ml of water (best if it is distilled, but not to worry if only tap water)
This is your SOLUTION A and it is good stored in a darkroom for a few months. Only mix it in the following step when you are ready to use it!
SOLUTION B: Mix 120 grams of SODIUM THIOSULFATE with 500 ml of WATER (again, distilled is best).
When you are ready to use a bleaching solution, mix 7.5ml of SOLUTION A with 180ml of SOLUTION B. Mix, and then add water until it is 500ml in total.
You now have a bleaching solution.
EITHER, put the whole image in the bleach and change the whole image lighter OR brush/sponge/add the solution to the photograph where you want it to be lighter.
Wash the image in WATER to clean off the bleach.
The final step is to FIX the image for 5 minutes in a bath of fixer OR a bath made of 10% SODIUM THIOSULFATE and water. Then wash it again and let it dry.