New to Gum Dichromate

[5artist5]

Hi all. Firstly I want to say that I really appreciate all of your help. It is great that there are so many people out there to be a support network.

Ok, the recent batch was done at 1gram pigment to 8ml gum.
I have been using the Windsor Newton gum. But I have powdered gum I could try if it seems like it might help.

I just got the book "The Gum Bichromate Book" by David Scopick.

 

[5artist5]

Not sure how to do the % calculation to determine ml of gum to grams of pigment? Is there a way to convert ml to grams? Or is there another way?

 

[koraks]

Not sure how to do the % calculation to determine ml of gum to grams of pigment?

You don't really have to. The main thing is to be consistent in your own workflow. If that ends up being something along the lines of "x grams of paint to y milliliters of gum solution", that will be totally fine.
If you really want to convert ml of gum to grams, you can multiply by around 1.1 and that will get you pretty close.

 

[nmp]

Not sure how to do the % calculation to determine ml of gum to grams of pigment? Is there a way to convert ml to grams? Or is there another way?

I think most people report % as weight/volume meaning weight of something divided by total volume of the mixture x100. For gum perhaps instead of using total volme, they just use the volume of gum - considering the small quantities involved. So in your case, it would be (1/8)x100 = 12.5%. This is only for comparison with what others are reporting. Otherwise as @koraks said as long as you are consitent within your own workflow, any measure should be be fine.

:Niranjan.

 

[5artist5]

So how much gum would you all recommend to add to .5g of pigment as a starting point?