Chemistry questions

I have a few questions about b&w chemicals. 1. Can you use the same fixer for paper and film? 2. How is the best way to discard chemicals when you have a septic tank. 3. There are storage times listed on ilford fixer/stopbath bottles that say how long you can store it. Is that for the diluted solution or the stock solution after it’s opened? 4. Can diluted D-76 or dektol be reused?

bdoss2006 said:

1. Can you use the same fixer for paper and film?

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Yes, but it's inadvisable to use the same batch of working strength first for film and then for paper. This is because film will leach out in particular some iodine, which will slow down fixing speed and efficacy in subsequent paper processing.

bdoss2006 said:

2. How is the best way to discard chemicals when you have a septic tank.

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Depends on which chemicals exactly and how much, and also what happens to the contents of the septic tank. There are quite a few discussions on this topic; I'd suggest to do a Google search on this forum and read through those threads.
Try this link with search results: https://www.photrio.com/forum/search/5674649/?q=septic&c[title_only]=1&o=date

bdoss2006 said:

3. There are storage times listed on ilford fixer/stopbath bottles that say how long you can store it. Is that for the diluted solution or the stock solution after it’s opened?

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Difficult to say if unspecified, but also largely irrelevant. Generally, fixer is OK until it starts to precipitate out (milky liquid and/or precipitate against the walls of the bottle). Used, working strength fixer I wouldn't keep around for more than a week or so. It'll start silvering out on the walls of the container it's in and by that point you can count on it depositing tiny silver particles on any film or paper you process with it as well. You really don't want that to happen.

Stop bath lasts indefinitely as a concentrate, but I always discard it at the end of a session since it's so cheap anyway. In a working strength solution, it tends to get moldy, especially the citric acid odorless stop bath.

bdoss2006 said:

4. Can diluted D-76 or dektol be reused?

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Dektol: yes, you could probably even use it as a replenished developer like I do with ID62. D76 can also be run in a replenishment system; google for it and you'll find formulas for mixing the replenisher. I think @Don_ih does this currently; he can maybe chime in as well.

Yes. To replenish D76 you need to mix up by scratch some replenisher - it's a different formula from D76. You develop your film in stock D76. Before returning that used developer to the bottle, pour in about 25ml per 36-exposure roll of film you are developing, and then only fill to the original volume (say 1 litre).

I only know of two issues with it:

First, your alkali has to match between the stock and replenisher. That more or less means you can only do it if you mix from bulk chemicals both the stock and the replenisher. You could probably find some D76R packets on ebay that would work with Kodak D76 (they don't make the replenisher anymore).

Second, Tmax is purely murderous to the stock solution. There are ways around it but I don't think it's worth doing. If you're planning on developing Tmax, I'd suggest not trying to replenish (and discard the used developer).

I have a sand mound septic system where I live, spent developer goes down the drain as does spent stop bath, no harm. Spent fixer goes into a "slop bucket" to evaporate. I don't generate enough spent chemicals to have to worry about disposal of the sludge in the bucket.

There's another reason to not use the same fixer for film and paper: the fixer gets paper fibres in it that will stick to the film emulsion.

bdoss2006 said:

I have a few questions about b&w chemicals. 1. Can you use the same fixer for paper and film? 2. How is the best way to discard chemicals when you have a septic tank. 3. There are storage times listed on ilford fixer/stopbath bottles that say how long you can store it. Is that for the diluted solution or the stock solution after it’s opened? 4. Can diluted D-76 or dektol be reused?

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Dear bdoss2006,

I am on a septic and I bring developer and fixer to the Household Waste dropoff centers run by the Illinois EPA. I'm sure you have something similar in Virginia.

The main ingredient of fix is widely used as a fertilizer additive. My guess is the silver is the main problem - if you extract it beforehand I believe there is no problem with disposal.

Rich Ullsmith said:

If you don't use pyrogallol or rodinal, just don't dump that or spent fix down your drain. Everything else is better than comet or bleach. Pyro and rodinal should not go down there.

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Rich,

I'm curious to know what the problem is with disposing pyrogallol or Rodinal in a municipal sewer system, or even a septic tank, for that matter. Could you elaborate please?

Doremus

bdoss2006 said:

2. How is the best way to discard chemicals when you have a septic tank.

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Sprint Systems says: In general, used darkroom chemicals, except fixer, may be disposed of in a municipal sewer system if one has a home-based darkroom. Used solutions should never be disposed of in a septic system. Septic systems are designed for biological treatment of standard household waste, and do not properly treat chemical wastes associated with photographic processing.

The underline and bold emphasis above are mine.

Kodak has also published unequivocal guidance on this issue: Don't dispose of photo-chemicals into a septic system. Sorry I don't have the link to that Kodak data just now.

The issue has been discussed exhaustively in this and other forums, with no more than anecdotes presented (as far as I know) advocating disposal in septic systems. The small darkroom hazardous waste 'problem' hasn't been addressed in any investigative literature that I've seen or heard about - no doubt it's dwarfed by a multitude of other polluting activities.

In the meantime, some manufacturers give explicit guidance for disposal of their products - Sino Promise's XTOL SDS sheets for instance, which state, in part: Collect and reclaim or dispose in sealed containers at licensed waste disposal site. Dispose of contents/container in accordance with local/regional/national/international regulations.

Disposing of used chemicals isn't as onerous as the quote from the XTOL SDS might make it seem. Check out some of the relevant threads.

The Kodak publication is J-300 - Environmental Guidelines for Amateur Photographers
Here is a link to the 1999 version: http://125px.com/docs/unsorted/kodak/j300.pdf

Thank you MattKing.

A very cursory www search for free household waste disposal services/events in Virginia turns up several possibilites - there may well be a program in the OP's area.

bdoss2006 said:

I have a few questions about b&w chemicals. 1. Can you use the same fixer for paper and film? 2. How is the best way to discard chemicals when you have a septic tank. 3. There are storage times listed on ilford fixer/stopbath bottles that say how long you can store it. Is that for the diluted solution or the stock solution after it’s opened? 4. Can diluted D-76 or dektol be reused?

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In the two-fixer- routine,You can use fixer previously used for film, as a 1st fixer for paper. For storing times,adhere to the manufacturers recommendations; they are typically for the stock solution.D76 is a film developer and best used one-shot for consistency. Dektol or D72 is a paper developer and can be reused as long as the paper achieves max black;when blacks start to get weak, replace it.

Buy some plastic five gallon construction buckets with lids, some 80 grit sandpaper and the blackest plastic spray paint you can find, and take an afternoon to lightly sand the buckets and lids exteriors.

Once sanded, paint the buckets completely black, as deeply as you are able to achieve.

Keep one for developers, one for stop baths/acids and a third for fixers.

Toners are used in smaller amounts so use a gallon milk jug, also painted black, for this material.

You can leave the lids of the buckets loose, just take a small drill and punch a pair of holes 180° apart and use cotters or cut rods, metal or wood or plastic to hold the lids in place, sitting on top of the bucket, no gaps, but
loose enough for vapor/moisture to escape.

Secure the containers, so they won't blow away/ tilt over, to the area you want it, tar driveways are great, but brick, stone, or cast stone works well, too.

Lastly, take a hot glue and on any perceived low spot on top of each lid, glue a soft, all cotton rag, old tee shirts are good, wide and long enough to go over the sides of the lidded buckets, to wick away rain/sprinkler water that the lids would otherwise hold, preventing mosquitos.

Punch a hole into the milk jug for evaporated moisture.

Do no use terry cloth, as I believe blood suckers can lay hatchlings in it, like they can on vegetation.


The point is, you can safely evaporate water away from the chemistry, leaving a dry or greatly reduced water content over a long period of time, desposing of the waste safely.

Toss some baking soda in the acid bucket, time to time, and an oil free steel wool into the fixer to plate out, to the bucket's side over a long period of use.