U of S | Mailing List Archive | alt-photo-process-l | Re: Do dichromates change with age?

Re: Do dichromates change with age?


This page says:
"...It is non-caking and if stored in a cool, dry place away from heat,
shelf life is indefinite..."

Another thing to consider would be contamination...


14 Temmuz 2008, Pazartesi, 4:44 pm tarihinde, Loris Medici yazmış:
> Hello Sam,
> A question: does your unit have a light integrator? If yes, by saying
> "longer exposure time" you mean "more units" right? If not (more units),
> then could it be that your lightsource is getting weaker somehow (either
> due bulb wear and/or voltage fluctuations)... Have you absolutely ruled
> out probable problems about electricity / integrator / bulb ect.?
> Regards,
> Loris.
> 14 Temmuz 2008, Pazartesi, 4:30 pm tarihinde, sam wang yazmış:
>> Has anyone come across any data about whether dichromates losing
>> speed, or effectiveness?
>> My jar of ammonium dichromate is probably over 20 years old (yeah, I
>> use very small quantity in gum printing) and it appears to suddenly
>> need longer exposure time. Doesn't make sense, especially since I'm
>> using an Amergraph printer for exposure. Humidity and everything else
>> has been kept fairly consistent.
>> Anyone else has similar experience?
>> Sam