Film & darkroom
Label stock solution separately from working solution
Prevent two different concentrations from looking interchangeable.
A prepared bottle needs to state what is inside, not only the product name.
Write the concentration clearly
Record the product, preparation date and whether the bottle contains concentrate, stock solution or a working dilution. Use containers and labelling appropriate for chemicals, never food or drink containers. Keep the current manufacturer’s instructions available so another session does not guess from a handwritten brand name alone.
Evidence: Technical data sheet
Check before pouring
Read the label and session plan together. Do not top up an uncertain bottle with a different strength to make its volume convenient. Keep unknown or waste chemistry separately identified and follow the appropriate local disposal route. A legible label is part of the workflow, not proof that an old solution remains usable.
Evidence: Manufacturer guidance
Sources & further reading
Sources for the specific facts and product descriptions above. Our worked examples, interpretations and practical suggestions are original editorial guidance.
- ILFORD PHOTO — PERCEPTOL, ID-11 and MICROPHEN technical dataTechnical data sheet
- ILFORD PHOTO — health, safety and disposal guidanceManufacturer guidance