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Mixing a Dichromate Solution

This step is DANGEROUS!!

Remember that dichromate is a bad substance for your health. Refer to the MSDS for more information.

It is easy to mix a dichromate solution. I use an 8oz. travel shampoo bottle seen to the right. I marked the side in ounces and labeled it accordingly so everyone that might see it will know it is poison and hopefully will not try to drink it. It unfortunately resembles Kool-ade and might be attractive to children, so its best to keep it out of sight and reach.

To Mix:

1. Fill up your bottle with warm or hot water
2. Pour the determined amount of dichromate crystals needed (see table below) slowly and carefully
3. Close it up and shake it gentle but well letting the crystals dissolve into the water
4. BE CAREFUL!! Dichromate dust can get into your lungs and on your skin if you are not cautious.

Further Information

The Ammonium Dichromate solution can be kept out in the light with no problem. I'm not sure how long it will last sitting there, but I once had a bottle of solution sitting around for over a year and nothing changed about its quality or the way it worked.

If you left the bottle open for a year somewhere, the worst that might happen is the H2O would evaporate and you'd be left with dichromate crystals once again inside your bottle. Just add water.

Ammonium Dichromate solubility is 36.4 g/100 g water at 68F according to the MSDS. I often see that you should mix ammonium dichromate to its saturation point, where the water can no longer dissolve the dichromate crystals because there is no more space between the water molecules. I never have mixed my dichromate solution to its saturation point so I cannot comment.

I learned to mix dichromate at a ratio of 1:10, and have always done so with no problems with it working. If I started with 1000 grams of water, I would mix in 10 grams of dichromate. Doing a bit of math, I find that I personally mix dichromate at about 27.5% of its saturation point. I'm sure changing the ratio of dichromate to water changes the exposure time required while printing, though I am not sure...more tests to perform perhaps? Regardless, I am using less dichromate and its always nice, if not essential, to not be wasteful.

Here are helpful formulas to determine how much dichromate to mix:

Which Formula to Use?

Like I said, I mix mine at 1:10 and have never had a problem in doing so. I use an 8oz. bottle and by using my formula in the table above, I see that I need about 10.5 ml of dichromate crystals to add to my 8oz. of warm water. (ml usually refers to a volume of liquid, not a volume of crystals, but I let this fact slide).

I use an old 35mm film canister marked in 5ml increments to measure my 10.5 ml of crystals. I don't worry too much about precision and just eyeball my measurements to approximately 10 ml. I use a sheet of paper beneath, to catch any falling dichromate crystals. When I'm finished I fold he paper and pour any remaining crystals into the 8oz. bottle as well, tapping the backside of the paper to be sure everything goes in.