Ammonium Dichromate Questions

[Clocker]

I have a small bottle of Ammonium Dichromate in solution that is about 2 years old from a cyanotype kit that I have never used yet.

It has just been sitting in a box in a bag in a dark area for that amount of time.

How light sensitive is this chemical solution by itself, before it is mixed with the other dry chemicals in the kit?

Would it still be any good after after aging and minimal exposure to indirect light that is probably stronger than recommended when all the chemicals are mixed?

It has not been mixed yet, so I just want to know if it can still be used to make the cyanotype solution.

 

[Jim Noel]

All of the chemicals involved are cheap enough to give it a try. I believe it will be OK

 

[Vaughn]

As long as there is no organic material in the solution of Amm. dichromate, it should be fine.

 

[Mike Wilde]

As Vaughan said. It is an oxidiser - if there are organics common to its solution to oxidize, it may be lacking in pep to do all of what you want it to do when mixed into the cyanotype solution.

I usally add amm bi/dichro drop wise to fine tune the contrast resonse after I mix the basic chemicals and expsoe a step wedge to see what the sensitivity and contrast the fresh batch is exhibiting.
So even if it is weakened, just add a few more drops in, if the mix looks like it needs it to mate to the response of the large format/ enlarged negatives you want to work with.