Old cyanotype chemicals

[kevin klein]

I have had the same two chems for the past 7 or 8 years, the prints seem to print out slower. What is the useful shelf life of the dry chemicals?

 

[cliveh]

I have had the same two chems for the past 7 or 8 years, the prints seem to print out slower. What is the useful shelf life of the dry chemicals?

If dry powder form and sealed from air, almost indefinitely.

 

[Loris Medici]

kevin I have 11 years old solutions still working OK. Dry chemicals are stable too - if kept well and incontaminated.

 

[Gerald C Koch]

You don't say what chemicals you have but if they are for the classic process then it depends on the chemical and whether it is in solution or not. I would discard any solutions. Dry potassium ferricyanate will keep. However ferric ammonium citrate may or may not still be good. It must be protested from moisture and light. This chemical should look like green scales.

 

[hermit]

Kevin;

I've never had problems with the dry chemicals as I buy them bulk and normally 5 + years before I reorder. Also have had solutions if kept sealed last well over a year with no issues.

 

[kevin klein]

Thanks everyone. I have ordered some Masa and Strathmore 300 scetch paper to try out.

 

[Mark_S]

Kevin

I have been printing Cyanotypes and getting good results on Rising Stonehenge paper.

Mark