Universal acidic fixer
Silberra FIXER A1 (Acidic fixer) is suitable to process any silver based negative photographic materials: photo film, photo papers or photo plates. Using Silberra FIXER A1 excludes dichroic fogging and lowers intermediate washing time for film between developing and fixing stage when no stop baths is used.
Chemical Composition
Sodium thiosulfate, potassium metabisulfite
Preparing Working Solution
Working solution is prepared by pouring the contents of the packs into water while continuously stirring the solution (use glass stick or special plastic stirring stick for chemicals). Distilled or filtered water is strongly recommended.
The method of preparation is as follows:
1) Warm 400-600 ml of water up to 55-60 Celcium degrees (use mix of hot and cold water, or use microwave for warming up the water).
2) Pour contents of pack #1 into the water while stirring until the powder is completely dissolved.
3) Warm another 200-300 ml of water up to 25-30 Celcium degrees (use mix of hot and cold water, or use microwave for warming up the water).
4) Pour contents of pack #2 into the water while stirring until the powder is completely dissolved.
As soon as both solutions are ready (powders are totally dissolved), add contents of the second solution into the first one while actively stirring and then add distilled water up to 1 litre in total volume. Allow the solution to cool to room temperature, nominally 20-22 C; wait for 1 hour prior to using it. Filtering the solution is not obligatory but recommended option.
Fixing Time
Silberra FIXER A1 stock solution fixing time is
7-12 minutes for b&w photo film,
10-15 minutes for baryta based papers,
5-7 minutes for RC based papers.
Ideal fixing time for each specific (and/or unusual) b&w film is calculated as triple whitening time. Whitening time is the time unexposed film needs to become absolutely transparent since immersed into fixing solution. Use lab timer and tweezers to get whitening time for a small stripe of unexposed film you're going to fix. Don't forget to triple that time to get real fixing time.
There is no need for additional tests to get fixing time for photo papers: always use the above shown time.
Usage Limit
1 liter of Silberra FIXER A1 can be used to fix up to 15 rolls of film or 30-35 sheets of 18x24 cm photo paper.
Restrictions
Never use the same working solution to fix photo paper and film.
Storage
Keep your Silberra FIXER A1 working solution in a cool, dry and dark place. Keep away from children. It is optimal to store your working solution in opaque, chemically inert and tightly sealed containers with minimal air space in order to reduce oxidation. Strong ammonium scent may indicate that fixer working solution is completely depleted and shall not be used any longer.
Expiry date/ Shelf life
Shelf life of Silberra FIXER A1 is 24 months while in original sealed packs. Silberra FIXER A1 working solution can be stored up to 6 months past the date of dilution; for partly used working solution storage period is no longer than 3 months.
Disposal Regulations
Silberra developers and fixers must be disposed of in accordance with the rules and regulations of the country they are used in. Concentrated developers could be toxic and may harm the environment unless disposed in appropriate manner. Silberra recommends to use special disposal services provided by correspondingly licensed organizations which are eligible for photographic chemistry recycling/disposal.