Storage life of thiourea/thiocarbamide and sodium hydroxide solutions?

[Steve Goldstein]

I'd like to experiment with split toning using a mild rehalogenating bleach followed by a thiourea and sodium hydroxide toner. How long can I expect separate 10% solutions of thiourea and sodium hydroxide to last? They'll be mixed together at the time of use. I know I should store the lye solution in plastic (HDPE or PET); is HDPE/PET OK for the thiourea solution or should I use glass? While I believe the lifetime of the sodium hydroxide solution is pretty much unlimited, Google has not (yet) provided me with answers relating to thiourea (also referred to as thiocarbamide).

Thanks!

 

[Molli]

I've had 10% solutions of both stored for the past eighteen months (the sodium hydroxide is in a thoroughly washed out container which previously held Ilford Multigrade Paper Developer and the thiourea is stored in a glass bottle simply because it was all I had on hand at the time). Both stock solutions seem to behave in working solutions exactly as they did when I first mixed them.
I'm a complete novice with toning and I haven't run any sort of scientifically acceptable comparative tests so please take my experience as just that!

 

[R.Gould]

I've had stock solutions stored for 3 or 4 years and still working well, Iv'e had the W/S solutions stored in plastic bottles for 12 to 18 months, still working well, so to me it seems that both the stock and WS solutions keep well, I test the W/S with an old print, maybe a test print or something before I commit a good print, if it is still working I use it, if not then mix up fresh,
As above i haven't any scientfic tests, just my many years of practical experiance

 

[Rich Ullsmith]

Concur, I have both in those plastic hospital saline drip bottles for 4+ years now. Admit, I was a little worried about the NaOH, but there it is, and I use it to refresh from time to time.