Replenishing Developers?

What is the difference between replenished and non-replenished systems in b/w

film developers?

 

Why can I replenish D76 with D76R?

The idea of replenishment is that you maintain a large jug or tank of developer, and after you process each batch of film using (all or some of) it, you add "replenisher" which reverses the chemical changes to the developer caused by developing film in it. So you undo the "using up" of the developer.

 

All color film processing systems are designed for primarily replenished operation.

 

Replenishers are generally different in formulation from the base developer, because only some of the chemicals in the developer are "used up" by processing films. They generally have less of things like the buffer and the restrainer.

 

There isn't much "volume" B&W processing anymore. Also, B&W developers are pretty darned cheap. So, the market for developer replenishers is dying out. Kodak has discontinued all the dedicated replenishers (for Microdol-X, D-76, and HC-110) for lack of sales.

 

Only TMAX RS remains from Kodak as a B&W developer with replenisher available, only because the developer and replenisher are the same formula.

 

If you are doing a lot of processing, replenishing can save money, and yield very consistent results. But you may also need to fine-tune the replenishment rate (how much you add for each square inch of film processed), else the developer will get more or less active over time. Also, replenishment doesn't make up for plain old aging of the developer, particularly by oxidation. You still have to throw out the entire jug or tank after a month or so.

 

If you want to replenish with Kodak developers, and use something other than TMAX RS, you'll have to mix you own replenishers from scratch -- but the only published one is D-76R. Of course, if you can mix D-76R from scratch, you can also mix D-76 from scratch -- and it's dirt cheap from scratch! So why replenish in that case?

You can make your own replen, but why. To maintain that you need to run a min volumn,

control strips, and check them with a densitometer to be sure you are not over/under

developing.

 

Use one shot and toss them out or add 10% time to a second run in 8 oz.

Many years ago I used ethol UFG with replenishment. I found that the more film I developed in the same batch the finer the grain looked. It isn't easy to be consistent because it's hard to know the exact condition of the developer at all times. The closest thing we have to a replenishment system today is divided developer like Diafine. It isnlt reallly replenishment in the strictest sense and contrast is different but you do use the same chemicals over and over until the Part A is depleted. You also have to be careful to keep things filtered when you run so much film through the same film developer.

Replenishment has been designed for volume operations (commercial labs)developping every day (or so) .A good replenishment requires tracking(densitotometry) to measure your solution activity. Used solution go bad much quicker not to mention contamination. Solutions that are not up to par will lead to hard to print negatives (if apparently they seem to look good).We had a commercial lab and when B&W production lowered to 10 films a week, we opt out of replenishment ,it didn't worth time/money to keep doing it.That actually could have been done earlier.

XTOL can be replenished in the same way as TMAX RS.

A bunch of worrywarts, my Daddy would call them. I used D-76 and other developers with replenishment in my home for years. Nobody ever told me I had to do a lot of measuring and book keeping. The instructions called for adding a certain amount of replenisher to the storage bottle for each roll of film developed, before returning the used developer. If you had some left over, you pitched it. Many old timers thought the developer got better as it was used.