Someone has an expired patent on a mixture that makes an oil painting medium. I will not use real names, but here are the ingredients of it
Painting oil + Stone dust (gives medium a certain quality to it).
I want to make that patented medium thicker, by adding one ingredient, a third mineral dust.
So I would like to get patented this:
Painting oil + Stone dust + my mineral dust thickener
If my medium behaves a little thicker than the previous patent's medium, is the difference enough to enable me to patent my mixture and then sell it as a product in the market or license the patent to producers?