Pyrocat-HD shelf life

[kunihiko]

Hi<BR>

I've checked the archive but I couldn't find what I want to know. I'm

sorry if this question has been already answered.<BR>

I've been using Pyrocat-HD as my standerd developer for a while and I

like the results. I don't shoot much, so I want to know how long can I

keep them in my shelf. Does anyone know that how long the stock

solution keep its performance ?

[andrew_oneill]

Solution A, 6 months and that's pushing it. Solution B indefinite. Have you tried mixing smaller portions? Instead of 1000ml, try 100ml.

[andrew_oneill]

Here's the formula:

 

Stock Solution A

Distilled Water 75ml

Sodium Bisulfite 1.0g

Pyrocatechin (Catechol) 5.0g

Phenidone .2g

Potassium Bromide .2g

Water to 100ml

 

Stock Solution B

Distilled Water 100ml

Potassium Carbonate 100g

[jay_de_fehr]

Kunihiko,

 

you can dramatically extend the life of the stock A solution (decades)by dissolving it in propylene glycol instead of water. The B solution will keep for quite a long time (years), and is relatively inexpensive in any case. Enjoy.

 

Jay

[jeffrey moore]

The creator of Pyrocat-HD, Sandy King, hangs out in the B&W forum on the APUG site (www.apug.org). If you post your question there you will very likely get the answer straight from the horse's mouth, so to speak.

[sandy_king]

Based on my own tests, and the reported experiences of many other users of Pyrocat-

HD, I estimate the shelf life of Stock Solution A, mixed in distilled water, to be on

the order of about 8-12 months, +/- 3-6 months for unfavorable or favorable

storage conditions.This assumes no contamination of one of the stock solutions with

the other.

 

As Jay mentions, mixing Stock Solution A in propylene glycol gives the Stock A

solution very long shelf life, on the order of years and years.

 

Sandy

[kunihiko]

Thank you all !<BR>

Since we don't have much information about Pyrocat-HD in Japan, your answers are very helpfull.<BR>

I would try propylene glycol next time.