How long can I use printing chemicals?

Can I re-use my developer, stop, and fix when printing? I use EcoPro chemicals for all 3. 99% of the time I am developing on 8x10 Ilford MGFB paper. I usually mix a liter of solution and would print about 20 sheets per session maximum. Can I re-use any of these chemicals after the fact? If I decide to store the chemicals, how long will they last?

Thanks

Print developer oxidizes quite rapidly, but if you only use it a bit and want to save it for use the next day, you can likely get away with that, but it won't last more than about 24 hours.
Stop bath can be re-used until exhausted, as can the fix. In fact, you should always be saving and re-using your fixer, whether its used for film or prints. Modern Rapid Fixers last quite a while and you can get good mileage out of them (but learn how to evaluate them for exhaustion).

retina_restoration said:

Stop bath can be re-used until exhausted, as can the fix.

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With respect to stop bath, this is correct, but you need to be careful about one thing.
If the stop bath is citric acid based, which most low odor versions are, a working strength citric acid based stop bath provides an excellent environment for the growth of mold.
So while a stored bottle of working strength stop bath may still have chemical capacity, you want to avoid using it if there is evidence of mold growth.

If your concern is using the minimum amount of chemicals -- to save waste, money, etc. -- the best way is to use tubes for prints. Each print will always get fresh chemicals -- and very, very little of them. Tubes are cheap and will pay for themselves in a few hours with the chemicals you save.

Based on your through put of 20 10" X 8" prints per session, I would suggest you use fresh developer for each session and the stop and fix may last for about 5 sessions, with the stop (an indicator stop would be a good idea) replaced depending on the strength.

At a point the developer stops working. That is a big hint.
Stop bath with indicator turns purple. That is a brightly colored indication.
Fixer fails testing with Hypo Check. That is another indicator.

After a while, when one of these goes bad, it is getting to the point that all of them should be replace.

AlexHaight said:

Can I re-use my developer, stop, and fix when printing? I use EcoPro chemicals for all 3. 99% of the time I am developing on 8x10 Ilford MGFB paper. I usually mix a liter of solution and would print about 20 sheets per session maximum. Can I re-use any of these chemicals after the fact? If I decide to store the chemicals, how long will they last?

Thanks

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A replenishment based system, like with Ethol LPD, uses about an ounce per 3 sheets of paper.

Simply pour 1 ounce of stock solution in the working solution bottle (per 3 sheets developed) and then return what will fit from the tray; Discard the rest.

Easy way to discard only the amount used during a session...

Print developer can last two sessions if stored well between sessions (air-tight bottle or plastic wrap covering the tray and lying on the surface of the liquid) if the 30-40 8x10 per liter throughput hasn't been reached.

An acetic-acid stop, like Kodak Indicator Stop will last till it stops looking bright yellow (don't wait till it's turned entirely purple before discarding it and mixing new!). You can store it in a bottle between sessions and it lasts for months. Citric-acid stops, like Ilfostop, are best used one session or for just a couple consecutive days.

Fixer capacity and tray life depends on both throughput and age. Check out the Ilford tech sheet on their fixer products (Rapid Fixer/Hypam). The information there applies fairly well to other similar products.

Note that film fix should not be used for fixing prints. Keep your film fixer separate and note throughput. Learn how to do a clearing-time test for film as a guide for both minimum fixing time and capacity. FWIW, I like to fix film longer than the minimum. There's lots of information on this here and over at the LF forum.

Capacity for fixing prints depends on what kind of paper you use (RC or fiber-base) and to what standard of permanence you desire to fix to. With RC paper and "commercial" or "general-purpose" levels of permanence, 40 8x10-inch prints per liter is a good throughput capacity limit.

If you process "archivally" and print on fiber-base paper, then things get more complicated. Two-bath fixing is often recommended to increase capacity. Otherwise, throughput capacity for a single-bath fixing regime for fiber-base paper for optimum permanence is only about 10 8x10-inch prints per liter (yes, only 10).

With a two-bath fixing regime, you can double that capacity. Mix two identical fixing baths and fix prints for half the fixing time in each bath. After 35-40 8x10-inch prints per liter throughput, discard fix one, promote fix two to the fix one position and mix a fresh fix two. You can repeat this cycle four or five times before needing to mix both baths fresh.

Working solutions of print fixer can be stored in tightly-capped (as full as practical) bottles for a few weeks between sessions. Working solutions will last about a week in open trays.

There's a lot more info in the Ilford tech sheets I mentioned above.

Hope this helps,

Doremus

Print drums are very economical and therefore you have to worry less about reusing your chemicals to get maximum value, but a pain to have to keep drying in between each print or batch. I believe there are some paper developers that are advertised as longer life even in working strength (Ansco 130 I think is one of them).