A friend of mind asked an interesting question; If I start out with 8oz of clear, how much toner should I add to get color? 

I got to thinking about this. I'm sure Mark Scarborough will chime in, but here what I told him:

Well, unfortunately, the answer is, it depends. Different mixes (colors) need different amounts of binder (clear). The way I usually do it is to go to the paint shop and have them mix up a pint of color as if they were mixing it up normally, just leave the binder out. What I get is a partially full pint can with toner in it. I finish filling the can with clear dope and shake it up. What I get is a can of colored dope.

I have also gotten full pint cans of toner. Usually primary colors, but occasionally not. For instance, I have a full pint of GM Atlantic Blue (a sort of metallic blue-gray) that I had planned to use for some project or another. I don't know what the mix ratio for this stuff should be. The rule of thumb is, mix in the toner until the paint is solidly opaque (if using opaque colors - different deal if you are mixing transparents like candy colors). Usually, reds and yellows need a lot of toner as does white. Blues, greens and of course black not so much. I've been able to get away with as little a 15% toner when mixing black; blues and greens are usually in the 15-40% range. Reds, yellows and whites are usually in the 50-80% range. More binder is better for adhesion, but may take more coats to cover. If you use a lot of toner in a particular mix, which happens sometimes with white particularly, it's a good idea to seal the color down with a coat of thin clear. Maybe 80% thinned. This penetrates to the substrate and can lock the color down. This is also true with silver or gold since they are usually 80% or more toner. Toner is lighter than binder (it's true, I've weighed them) so it's a judgment call. More toner is less coats, but you have to be careful due to adhesion issues.

Just thought others might find this interesting.