precipitate in developer

[jgcull]

There is still some fine precipitate (is that what you call it?) in my d76 I mixed this morning. Eventually it will all dissolve, but I wanted to process some film now. Will it mess up my negatives if I use it with that present?

Thanks.

Janet

[Mick Fagan]

Janet, I mix D76 from scratch, I always filter it through a coffee filter sitting in a funnel.

Regardless of how short or long the developer has been sitting, there is usually some very fine particles, I just filter them out.

You may find, if you have used tap water like I do, that there will be some precipitate, especially after being left for a day.

Mick.

[Nicholas Lindan]

Originally Posted by jgcull

There is still some fine precipitate (is that what you call it?) in my d76 I mixed this morning.

This is often precipitated calcium from the tap water.

A 1/4 tsp. of EDTA per liter of water takes care of it. The EDTA should be added to the water before you add any other chemicals. I have the impression that EDTA makes the stock solution last a bit longer, but I have no evidence of this. The quantity you use isn't critical, if you still get white stuff add a bit more.

Hexametaphosphate (the old Calgon, not the new stuff on the grocery shelf) will also work.

I have tried filtering out the precipitate but the developer just clouded up again a few days later. With EDTA it stays clear to the last drop.

What it is that is precipitating is most likely different with different city water supplies. Filtering may work with some tap waters - may as well give it try, coffee filters are cheap enough.

EDTA is available from Photographers' Formulary.

[jgcull]

I never have trouble with it clouding. Just little white specks. I've always thought the problem was that it hadn't yet dissolved completely and I was rushing things. Never occurred to me it could be my water. Anyway, I strained it through a coffee filter and all is well.

Thank you, both!