Has MY PyrocatHD (A) Died ?

[Ian-Barber]

Could this mean that WPS could be using Sodium Bisulphite in place of Sodium Metabisulfite?

 

[Ian Grant]

Could this mean that WPS could be using Sodium Bisulphite in place of Sodium Metabisulfite?

Highly unlikely, I've never seen Sodium or Potassium Bisulphite sold here in the UK except as a very expensive analytical reagent, and that's special order.

Eastman Kodak supplied Sodium Bisulphite to Kodak Ltd at one time, but any still around would be very old. It's probably more about the way Metabisulpite is made in Europe to a higher purity, the Kodak Bisulphite was supposedly around 70% Metabisulphite, it's still an anti-oxidant/reducer just not quite as effective.

Ian

 

[Ian-Barber]

From what Ian G has indicated, the likely cause could be something to do with the quality of the Sodium Metabisulfite or the Pyrocatechin as he has already stated that the black bottles it was supplied in look adequate.

So for future reference where you suggest the best place in the UK is to buy Pyrocatechin and Sodium Metabisulfite for those who want to mix their own.

PyrocatHD (A) Ingredient
Distilled Water (50¡ C) 750 ml
Sodium Metabisulfite 10 g
Pyrocatechin 50 g
Phenidone 2.0 g
Potassium Bromide 1.0 g
Distilled Water to make 1000 ml

 

[David M]

As an innocent by-stander, I wonder if someone who knows about these things might publish a reminder of the precautions to be taken when working with raw chemicals.

 

[Alan9940]

Alan, Sodium Bisulphite doesn't form Metabisulphite when dissolved.

Since I'm not a chemist, I have no clue. I was simply passing on some info I got from a well respected dealer of raw photo chemicals over here. Does seem odd to me that he carries just about every photo chemical available, except Sodium Bisulphite. And, when I asked about it that's the reason he gave me for not handling SB.

 

[Alan9940]

As an innocent by-stander, I wonder if someone who knows about these things might publish a reminder of the precautions to be taken when working with raw chemicals.

Goes without saying...I think. When mixing something like Pyrocat-HD, I wear a smock, rubber gloves, eye protection, and a high quality respirator; and when mixing in whatever pyro-based chemical I do it outside.

 

[David M]

Alan,
The fundamental thing about safety instructions is that they don't go without saying.

 

[Alan9940]

Alan,
The fundamental thing about safety instructions is that they don't go without saying.

Agreed. But, I would like to think that anyone dealing with anything hazardous would understand the required precautions.

 

[David M]

I'd like to think that too, but there's no limit to human ignorance and stupidity, even (alas) among LF photographers.* We have to ask, how do they know it's hazardous if nobody tells them?
In my view, if I tell someone something they already know, I may offend them, but if they don't know, I may save their life. Being offended seems better than being dead.
A very simple example: Everybody knows the add acid to water not water to acid rule, don't they? Do they? It's not obvious. I add water to developer, water to coffee and tea, why not water to acid? It was the first thing I was taught in chemistry, before we did any chemistry. Get it wrong once, and you're blind for life.

*LF photographers do seem to be more sane and intelligent than most, but there's always one...

 

[martin henson]

LF photographers seem more sane and intelligent than most, pretty silly statement IMHO, I use all formats , and if they’re that intelligent then they don’t need lectures in safety procedures.

 

[David M]

Well, one LF photographer might be silly and I volunteer for that.
Intelligence is not the same as information. How can we know that one white powder is harmful and the other innocent? How do we know about cumulative damage until it's too late?
I did write photographers, not photographs.
There should be they're.
My apologies if you find my concerns offensive.

 

[Ian-Barber]

I managed to get in contact with Kevin from Wet Plate Supplies regarding the colour and this was his reply.

The colour is fine, it is this colour when its mixed with Glycol as it becomes more concentrated than when mixing it with just water.

 

[Alan9940]

I managed to get in contact with Kevin from Wet Plate Supplies regarding the colour and this was his reply.

The colour is fine, it is this colour when its mixed with Glycol as it becomes more concentrated than when mixing it with just water.

Umm, OK...makes no sense to me as I've been mixing my own, in Glycol, for years and never experienced anything close to a red color. Regardless, you'll know if it's good when you develop the first sheet of film. If I were you, though, I'd run a test sheet before committing to serious images.

 

[Alan9940]

@David M, MSDS? I know what you mean, though...I always prefer to err on the side of caution and not assume what folks know. Not related to photography, but related to the mixing of "stuff"...a few months ago we had EMT's running around the house across the street from us; the cleaning lady had passed out near her car! Hmm...mixing of cleaning products?

 

[Ian-Barber]

Umm, OK...makes no sense to me as I've been mixing my own, in Glycol, for years and never experienced anything close to a red color. Regardless, you'll know if it's good when you develop the first sheet of film. If I were you, though, I'd run a test sheet before committing to serious images.

Just going to have to put this down to one of those things I'm afraid as I poured it away last week. I don't know enough about the chemistry to have my own opinion. I do have some in a glass bottle from the same batch so I might run a sheet through it tomorrow and see what develops

 

[martin henson]

I think the best way is to test it, having said that how do we know it is working to full potential, it might seem to develop OK but does it affect the staining in any way if it's getting near the end of its shelf life !!

 

[Ian Grant]

I managed to get in contact with Kevin from Wet Plate Supplies regarding the colour and this was his reply.

The colour is fine, it is this colour when its mixed with Glycol as it becomes more concentrated than when mixing it with just water.

That's not correct at all, how can it be any more concentrated, glycol is colourless ? The two developing agents will dissolve in the glycol and the Sodium Metabisulphite and Potassium Bromide need a little water to dissolve.

I've mixed Pyrocat HD in Glycol and the colour is no different to when dissolved in water. I've bought Pyrocatechin a few times now, usually 500g or 1kg at a time and it's always a straw yellow colour in solution. Should add I've been using Pyrocatechin since the late 1970's when I worked as a Photo chemist.

Ian

 

[Ian-Barber]

I wasn't all that convinced from his reply to be honest, he sounded a bit vague.

It would have been nice to have found the answer because if the Pyrocatechin or Metabisulphate was a little old it makes me a little cautious for the next time I need to buy some.

All I can say is that the new stuff I have now is working fine and is a straw colour and although it may be a coincidence, I don't appear to bet getting any uneven staining anymore.

 

[Ian Grant]

If it's that colour when first mixed then it's the Pyrocatechin developing agent that's begun to oxidise during storage before mixing.

If it's fresh Pyrocat that's initially straw coloured and with storage turns that reddish colour it's a clear indication the developer solution has begun to oxidise and won't keep long..

As Ian saw on Monday I'm getting superb results with Pyrocat HD and HP5, and negatives that are so easy to print. It's great with Delta 100 and Delta 400 (120) as well but I suspect I may be amazed at 5x4 FP4 in it, great results with Acros too but I prefer Delta 100.

The staining component with HP5 is very noticeable, the only film I've uses with similar staining was (or rather is as I have some 10x8 boxes left) Fortepan 200. How best to describe the staining component - as the exposed silver halide develops exhausted developer produces a staining dye a touch more diffuse than the silver grains, sort of fills in the gaps, so apparent graininess is fine, but there's also tanning taking place so adjacency effects. The result is increased sharpness, and fine grain, no blocked up highlights, and a pleasure to print ;D

Ian

 

[Ian-Barber]

If it's that colour when first mixed then it's the Pyrocatechin developing agent that's begun to oxidise during storage before mixing.

This may be the answer as he did tell me that it was this reddish colour right after he mixed it