Benzotriazole and KBr appearance

[eclarke]

Mortar and pestles must be more common over here for kitchen stuff; they seem rather ubiquitous. I know what kind of coffee grinder you're talking about, my parents had/have one of those (and it's hard to get a decent even grind with it) and it does kick up some dust as it's going and when you open the top up.

I like Germaine"s finegrain in some situations and have a coffee grinder devoted to just PPD, the stuff is always in big rocks and takes forever to dissolve even with my heated stirrer. Interestingly enough, the Germaine's has a purple color if I dissolve the rocks and a straw color if I pulverize the PPD. It doesn't seem to make any difference in the development....EC

[Photo Engineer]

Both are normal. BTAZ should be dissolved in alcohol, but NEVER use denatured alcohol as one denaturant used has photographic effects.

I break up the KBr with a normal chemists spatula. You can probably get one from a druggist.

PE

[Photo Engineer]

If you use a mortar and pestle, you should use the glazed ceramic or glass. The unglazed version is impossible to wash chemicals out of. Druggists use the glazed or glass type.

PE

[Kirk Keyes]

If you want to show off to the neighbors, get an agate mortar and pestle. They are generally small, but they sure are beautiful.

[Murray Kelly]

PE - my denatured alcohol uses Gameaux mixture .25% as the denaturant.
This is mostly methyl isobutyl ketone and tiny amts. of other things. Do you mean this denaturant is incompatible with photographic chems?

Thanks
Murray,
Brisbane

Both are normal. BTAZ should be dissolved in alcohol, but NEVER use denatured alcohol as one denaturant used has photographic effects.
PE

[Murray@uptowngallery]

Thank, all.

[Photo Engineer]

PE - my denatured alcohol uses Gameaux mixture .25% as the denaturant.
This is mostly methyl isobutyl ketone and tiny amts. of other things. Do you mean this denaturant is incompatible with photographic chems?

Thanks
Murray,
Brisbane

If you pour some of the alcohol into water and see a cloudiness form, then one of the ingredients can harm negatives. The cloudy particles can get into the negative, dry there, and leave white spots on your prints.

PE

[gainer]

I think you can keep the bromide in a weak solution, which makes it easier to measure out small amounts. You can weigh out enough to make the lumps negligible compared to the total weight, and let it take its time dissolving.

[Murray Kelly]

Thanks PE - I will try that. Iv'e never noticed it but then I wasn't looking for it.

Murray
Brisbane

If you pour some of the alcohol into water and see a cloudiness form, then one of the ingredients can harm negatives. The cloudy particles can get into the negative, dry there, and leave white spots on your prints.

PE

[Neanderman]

Don't think twice about buying a morter and pestle. And decent kitchen store will have all sorts of them available. I would recommend a stone or ceramic one -- they are harder and less likely to have a problem with carrying contamination over.

Ed