Benzotriazole and KBr appearance

Murray@uptowngallery · Dec 4, 2007

I got my order from Photog's Formulary today.

Two items had a surprising appearance...

The benzotriazole wasn't a powder but looked like spun fibreglass - long white strands..is that normal?

The KBr (potassium bromide) was in rocky chunks...I guess if one makes a huge bottle of it, a rock can be weighed & the water volume selected accordingly. I wanted to make a small volume but didn't realize I needed a mortar & pestle.

I have a spice/coffee grinder I plan to use to pulverize acetaminophen...I guess I could do that to have some control over how much chemical. Don't want airborne dust however...

Welcome to DIY, huh?

Phillip P. Dimor · Dec 4, 2007

I have benzo from photog's form. It is 'fluffy and needle-like' in appearance. Like cotton-candy almost. I believe it's normal (and really tough to get to dissolve!)

Akki14 · Dec 4, 2007

You'll probably get less dust with careful handgrinding with a mortar & pestle than with one of those impossible-to-clean-100% coffee grinders, IMO.

Murray@uptowngallery · Dec 4, 2007

This machine has a blade rather than a mill/grinder arrangement. I think it would be a good idea to never use it for food again...

I had a mortar and pestle as a kid with a science kit...I wonder what suspicion I would generate buying one these days...no worse than having a garage full of chemicals I guess.

Thanks for the appearance-verification, PPD.

eclarke · Dec 4, 2007

Murray,
A cheap hotplate from Walmart set on low,low heat will help you dissolve the benzotriazole and is useful for all formulation. If you could find a nice Corning heated stirrer, you will be in formulating heaven. You can probably get a good mortar and pestle at any Asian food market....EC

Akki14 · Dec 4, 2007

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.

juan · Dec 4, 2007

The appearance of both is normal. The KBr pellets will dissolve with stirring. I've done it by hand, but it's much easier with my magnetic stirrer.
juan

Murray Kelly · Dec 4, 2007

I disolved benzotriazole in denatured alcohol. 1% (1g in 100ml) is 10mgm/ml.
Disolved easily.

Murray
Brisbane

Mike Wilde · Dec 4, 2007

Chunky Bromide

get used to it - it will always chunk up. I have a small (3" dia) mortar and pestle devoted to just this chemical. I also ocassionally get a good sized pair of pliers down into my container of it to break up big chunks before I consign the smaller bits to grinding. Most of the time it is easier to make up a 10% solution of bromide in hot distilled water, and then just measure out the required mL to get the weight that a formula calls for. This means the pestle sees only seasonal use when the bromide bottle gets empty.

I deal with the BTZ the same stock solution way except I make it up as a 1% solution, since it is usually needed in such small amounts. Yes the material is certienly finely divided. One purchase of the stuff though, is usually a lifetime supply.

Peter Hogan · Dec 4, 2007

The BTZ if fine; white needle-like appearance, and it will dissolve readily in hot water. As already mentioned, Kbr will always form 'rocks'. It breaks up fairly easily and dissolves very easily too.

eclarke · Dec 4, 2007

Akki14 said:
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 · Dec 4, 2007

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 · Dec 4, 2007

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 · Dec 4, 2007

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 · Dec 5, 2007

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

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

Murray@uptowngallery · Dec 5, 2007

Thank, all.

Photo Engineer · Dec 5, 2007

Murray Kelly said:
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 · Dec 5, 2007

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 · Dec 5, 2007

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

Murray
Brisbane

Photo Engineer said:
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 · Dec 5, 2007

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

Murray Kelly · Dec 5, 2007

PE - I tried your test and there is no cloudiness of any sort with my denatured alcohol. Apparently Gameaux mixture is OK.

Thanks
Murray
Brisbane, OZ

Photo Engineer said:
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

Benzotriazole and KBr appearance

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