wiki:darkroom:chemistry:formulas:washaid
Table of Contents
Wash Aid (HCA)
Hypo Clear Agent (HCA) to accelerate the removal of fixer salts and decrease washing times.
Preparations
Kodak HCA
To mix from pre-mixed powder (provided by Kodak)
Kodak HCA
To prepare working solution from powder.
| Kodak HCA, | 26.5 gr |
| Water, | to make 1000ml |
Note: it is not recommended by Kodak to mix parts of the bag of powder, but this practice seems to work fine.
Hypo Clearing Agent
Mix your own HCA from raw chemicals.
Hypo Clearing Agent – stock
| Water (@52°C) | 750 ml |
| Sodiumsulfite | 200 gr |
| Sodiumbisulfite | 50 gr |
| Water | to make 1000ml |
Note: The sodiumbisulfite is to lower pH and prevent emulsion softening; may be excluded if the intended use is to treat prints.
To make a working solution, dilute stock solution 1+9.
Instructions for use
- Prepare a working solution; either from ready-mixed powder of mix from scratch (see above).
- Pre-rinse, treat in HCA and then make a final wash as specified below (minimum).
| Pre-rinse | HCA | Final wash | |
|---|---|---|---|
| Film | 1 min | 1-2 min | 5 min |
| 1 min | 3 min | 20 min |
Capacity
Capacity is approx 35 sheets of paper (24x30cm) per liter working solution.
Notes
This is the place to write down notes, tips etc.
wiki/darkroom/chemistry/formulas/washaid.txt · Last modified: 2022/01/26 12:22 by henpe