Question on Potassium Dichromate in Gum Printing

[Robert Ley]

I recently mixed up a 10% solution of Potassium Dichromate and I now have about a half inch of crystals in the bottom of my Boston round bottle.

I noticed this same problem with some 10% solution that I got from Bostick & Sullivan about a year ago.

Is this typical and if not how can I prevent this from happening. Will this affect my printing if I use this solution as is?

 

[Jim Noel]

Store it at 70 deg. If crystals form, stir,don't shake, to get them back in solution. A magnetic mixer is ideal for such mixing, as well as mixing all developers.

 

[Gerald C Koch]

The solubility of poassium dichromate is ~100 g/l at 15C. So if the temperature drops below this then some of the chenical will crystallize out. Always check the solution before use and warm it with shaking to get the dichromate back in solution. Shaking will not harm the solution in any way.