Discussion in 'Alternative Processes' started by Mustafa Umut Sarac, May 28, 2013.
Do pyro developers and dichromate generate fume in the darkroom dangerous ?
No, both are in aqueous solutions and the dangers of inhalation are very low.
Can I suggest that you shouldn't consider using Dichromate until you have read the MSDS?
It's pretty nasty stuff.
I believe mixing from powder is an issue. And you must be very careful. The chemists here can elaborate with the correct answer.
I have my pyro made and get it in liquid A and B form and I can say there is no issue using it this way.
A respirator (with the correct cannisters) is a good investment for handling toxic, carcinogenic and mutagenic solids, and toxic solvents. I always wear nitrile gloves when working with hazardous materials and yes--always read the MSDS before you work with any chemical.
If by pyro you mean pyrogallol then both the powder and solutions are very dangerous. In solution it is rapidly absorbed thru the skin. The LDlo (smallest lethal dose) is 26 mg per kg of body weight. Even in small amounts repeated skin contact should be avoided. Contact with dichromate solutions can cause skin irritation. Ingestion can be fatal in very small amounts. When dealing with the powders wear a respirator and nitrile gloves. With solutions gloves are still required. If possible I would recommend avoiding either chemical.
As an aside to this post can everyone please]stop using the word pyro. It is a very old-fashioned term and not a scientific name and is confusing because some people refer to both pyrogallol and catechol by using the same name pyro. So in the future let us all agree to use only accepted chemical names (those recognized by the IUPAC) in this instance pyrogalol and catechol.
I'm an offender of this and will try to make sure I am more specific. I agree, this is quite important.
Gerald and all Friends ,
Thank you for all answers ,
Could you please give me the correct respirator canister numbers for either dichromate and pyrogallol ? And how do they classified and subclassified either in Europe and US ?
Look for canisters that are rated for organic solvents. They should be more than sufficient for pyrogallol, pyrocatechin, and various forms of dichromate/bichromate.
Yes, the cannisters rated for organic vapors will also filter out very small particulates. When you weigh out materials--especially anything dusty--go slowly and carefully to avoid aerosolizing the material.
The problem with both these chemicals is from dust being inhaled during mixing of a solution. A good dust mask, goggles, nitrile gloves should provide enough protection. Once in solution the only danger is from skin contact or ingestion. Neither of these chemicals generates what is strictly speaking fumes.
However, catechol does have a measurable vapor pressure and the solid should only be used with good ventilation.
Thank you all.
Do catechol developer create danger with skin contact. I am not developing films for 20 years and it could be messy. I will use the bathroom to develop the films and is it safe to detergent and lots of water to clean the ceramic tiled ground or does chemical sticks to the piping and fume back from there ?
Skin contact with catechol is hazardous. If you thoroughly rinse surfaces that come into contact with the developer, they should be safe. Nitrile gloves will prevent most skin exposure, and you can be careful to minimize developer contact with surfaces you routinely touch, like a sink or tub. I'd dump the developer down a utility sink or toilet. There's no vapor hazard from washed surfaces.
Do I need to dumb the catechol developer after use or collect and pour back to developer bottle. How many times I can use a used developer ?
Thank you all,
Pyrocat HD (which I recommend) is one shot--discarded after development.
Thank you Barry ,
I love Sandy King Works very much and I googled it after you recomended and Bostick Sullivan sells total 1 liter two part Pyro HD developer for 26 dollars. It makes 50 liter developer and if my tank is 400 cc , it develops 110 rolls 6x6. It costs 60 cents per roll with shipping. If I buy a scanner , 110 rolls development and scan costs me 100 dollars. If I order it here , it costs nearly 800 dollars in Istanbul.
Staining developers are by their very nature intended for single use. This is because of the low level of preservative needed to produce a stain image. Only the concentrates have a shelf life. Once diluted they should be used immediately and then discarded.
I have been using the B+S Pyrocat for about 6 years now (?) and the only time I've had issue with the concentrate was after about 9 months, 1/4 full bottle of solution A went bad.
When tank developing, make sure to mix A + B during the presoak (if you do that) or directly before use, otherwise you'll get a weak image.
And as others have said, the stuff is fairly toxic so use common sense caution. My mother said I developed into a nice young man, but I don't think that was because of drinking the Pcat.
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