Film & darkroom
FOMADON R09: plan a documented black-and-white session
A liquid concentrate whose dilution must still match the film and process.
A small bottle can represent several different working recipes. Foma’s R09 is one example: identify the exact product rather than assuming that every bottle with a similar developer name has identical instructions.
Read the maker’s description
Foma identifies FOMADON R09 as a liquid concentrate for black-and-white negative films and lists 1+25 and 1+50 working dilutions on its English product page. Choosing between them still requires the matching film-processing information. Dilution alone is not a development time.
Evidence: Product documentation
Calculate after choosing
For our arithmetic exercise, a 1+25 mixture contains twenty-six total parts. If an approved recipe and tank require 520 ml, that means 20 ml concentrate and 500 ml water. This example illustrates the calculation; it does not establish the necessary capacity or time for a particular roll.
Record the actual conditions
Write the film, exposure index, chosen dilution, volume, temperature and agitation method before starting. Add the source and revision of the recipe. When discussing a result with another photographer, include these details alongside the image so that a different working solution does not masquerade as the same experiment.
Sources & further reading
Sources for the specific facts and product descriptions above. Our worked examples, interpretations and practical suggestions are original editorial guidance.
- Foma — FOMADON R09Product documentation