The spots in film can have several origins, from durty baths to unwanted incompatibilities. Sulfite is a silver halide solvent but also a silver solvent. If your developing tank has silver deposits due to prior utilizations, sulfite contained in the developer may dissolve that silver which may precipitate on the film lather, at least I think so. Cleaning the developer tank with a bleach bath to remove silver is a good practice on my point of view and this will be done next time I use the tank.
At the present, I am quite sure that Ammonium Thiosulfate is also responsible for some spots, mainly when using Caffenol and Vit. C developers and bypassing a good wash between developer and fixer. I joined to my previous developer Caffenol Strong, very little of CD4 and some water (50%) and this led to the concentrated solution:
0,5% Sodium Sulfite
0,6% CD4
10% coffee
10% Vit. C
This solution, to be added to the basic bath, is stronger than Caffenol Strong, and has half the content of coffee and Vit. C, due to the superadditivity already found. For the basic bath I used, last time, following mixtures:
4% Sodium Sulfite
4% Sodium Carbonate
0,1 % Potassium Bromide
The presence of sulfite is to lower the pH and get less grain, I aimed!
For the working solution I used 2% of the concentrate in the basic bath. I already developed a Ilford FP4 120 film, using 30 minutes at 18ºC. All 8 pictures are given below, made with my new selfmade camera with Leitz Elmar 50mm lens:
Church in Amor |
Center of Amor |
Falling down |
At the rear side |
View from the church |
Another view from the church |
Falling down again |
Passing by, 1/200 shutter speed estimation |
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