I am thinking of developing film and prints en-masse in a modern ceramic bath tub.

Is it safe to use developers like Rodinal assuming the bath tub is going to be used for baths later? Rodinal is ideal as stand development admits dilution ratios of up to 1:200. Will there be any other side effects?

Are there any recommended developers for this?

(Fixing will be done individually later)

  • 2
    \$\begingroup\$ nnnnooooooooo. stop. FILM EN-MASS IN A BATH TUB. ??? Do you have 1 1/2 foot x 3 foot sheets of film? they make large trays. Porcelain tubs would be ok. Fix later?, no fix directly after development. Can you please clarify this ill conceived plan in DETAIL. \$\endgroup\$
    – Alaska Man
    Jun 25, 2016 at 8:46
  • \$\begingroup\$ well, if you want to do dev lots of prints at once without enough trays, would the bath tub suffice? I thought that it is fine to fix any time after the stop bath. \$\endgroup\$
    – Alex
    Jun 25, 2016 at 9:23
  • 1
    \$\begingroup\$ It would be really interesting to get details of your plan. For example, you mentioned prints. So you have bath tub full of developer and tons of previously exposed papers. How do you manage to keep the dev time the same for all? Why would you expose many papers in advance if you can do it continually in trays with much better control over quality? \$\endgroup\$
    – MirekE
    Jun 25, 2016 at 16:35
  • \$\begingroup\$ @Alex , i am genuinely interested in why you want to do this. Can you explain the the steps in process as you in-vision it ? \$\endgroup\$
    – Alaska Man
    Jun 26, 2016 at 8:04

2 Answers 2


I think using a bath tub for development is a bad idea.

  • you won't be able to clean the bathtub perfectly, after some time you will have some stains in hard to clean areas
  • as far as I know the particular benzene derivative contained in Rodinal is not known as carcinogen, but many similar chemicals are and I would not expose naked bodies of innocent people to it. What if new testing is done one day and the rating is changed
  • bath tub does not have the most effective shape for development
  • you will need about the same amount of liquid for your stop bath and for fixer, you will need same size or larger containers for washing. You would need at least two bath tubs to do any development and ideally four or five to do it effectively

Film photography embraces the use of chemicals. For the most part, the chemicals we use are benign; otherwise the darkrooms of the world would be labeled as a hazardous workplace. Not to say there is absolutely no danger as the potential to mishandle chemicals is with us always.

There are a plethora of developer formulas, all have advantages and disadvantages. However, all developers are similar as to their potential hazards. The black & white developer, Rodinal included, consists of 5 chief ingredients.

  1. Water solvent: All the chemicals of construction are dissolved in water and water is the chief ingredient.

  2. Developing agent: A developer likely has two or more. These are organic chemicals able to reduce (liberate) metals from their salts. They have an affinity for oxygen. All are kinsfolks of benzene initially fashioned from coal. Spent developing agents revert to coal tar.

  3. Accelerator: The developing agents work in an alkaline environment. The more aggressive developers contain strong bases. Rodinal sets the pH alkaline using potassium hydroxide.

  4. Preservative: Sodium sulfite, reduces the potential for oxidation and neutralizes the staining agents that form from oxidized developing agents.

  5. Restrainer: Forces the developer to become selective. Without a restrainer the dev eloper will over-develop and thus fog the film. This chemical is potassium bromide.

Is this a particularly hazardous solution? Answer is no but – skin reactions with rash are not uncommon. Don’t drink or bath in this formula. Wash all vessels and utensils – use of rubber gloves advised.


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