I will first outline the process and then give you some of the formulas I
normally use.
0. GBC proportional sizing (optional)
1. 1st Coat
2. Dry
3. 2nd coat (optional)
4. Dry
5. Print
6. Develop
7. Clear
8. Rinse
9. Tone (optional)
10. Fix
11. Rinse
12. HCA
13. Wash
14. Dry
The following steps are optional but work very well both to protect the
final image and to improve tone separation at the higher densities.
They should not be used when the GBC proportional sizing is applied.
15. HOT gelatin coat
16. Dry
17. Hardening and clearing ( will remove even the more persistent stains
that step 7 could not clear).
18. Wash
19. Dry
Emulsion for one coat
Identical quantities of Ferric oxalate at 25% and Silver Nitrate at 20%
Adding platinum, gold or palladium salts gives interesting results.
(A) Developer
100g of sodium acetate
1000 ml of destilled water
Add sodium carbonate to a pH of 9
Add oxalic acid to a pH of 7
4g of tartaric acid
2g of citric acid
2g of sodium difosfate
20 drops of Agepon
Potassium dichromate as per required contrast ( 10 drops of a saturated
solution at 20ºC give me the contrast to print negatives with a 1.5 density
scale beteewn zones 1 and VIII)
(B) Developer
150 g of Ammonium citrate
15g of Sodium Citrate
4g of Citric Acid
20 drops of Agepon
Potassium dichromate as in (A)
Mix (A) and (B) to get the colour you want.
I suggest printing one photograph cutting it to 15 identical pieces and
develop each one in a different combination of (A) and (B), from
100%(A)+0(B) to 0%(A)+1005(B).
These different colours will be a good guide if you want to try the
glycerin development. I normally mix identical quantities of glycerin and
developer and then use a brush for development.
Clearing
The Sodium Citrate + Citric acid clearing bath solves almost every problem.
I suggest using 2 baths one after the other, as for archival fixing.
30g of Sodium Citrate
10g of Citric acid
1000ml destilled water
Toner
I favour the gold / platinum citric acid toner
Fixer
50g of hypo
4ml of ammonia
1000ml of water
Step 15
40g of gelatin
1000ml of destilled water
20 drops of clorox
Use at 70ºC!!!!
Step 17
150g of potassium alumen
50g of citric acid
1000ml of water
Carlos Gasparinho
nop51076@mail.telepac.pt