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

Re: Do dichromates change with age?

Hi Loris,

The bulb is quite new, and I haven't noticed any speed loss with palladium. The integrator on the Amergraph reads UV, so that's the reason I replaced my old NUARC with it (integrator in the NUARC reads visible light).

There are many other possible answers. Just wondering if dichromates could lose potency.


On Jul 14, 2008, at 9:44 AM, Loris Medici wrote:

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.?


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?