MITRA Forum Question Details

EditDeleteUnfortunately if you are able to easily scratch off layers of paint this means that there likely was not sufficient tooth in the underpainting....however the ground could also play a role in this problem. As you stated, you found that your Titanium White was particularly "fatty" so this may have been the culprit in the end...but using Titanium white itself should not be a huge issue (as opposed to using pigments that are notorious for slowing the dry time of the paint or pigments like Zinc white that are now known to cause problems down the road). Things to maybe think about: 1) the absorbency of your ground 2) potential separation of the pigment(s) from the binder in the tube, inadvertently leading to "fattier" paint being squeezed from the tube 3) using a touch of solvent in your initial paint layers if they are too fat to begin with, using less and less (or even none) in subsequent paint layers. Hopefully this offers a bit of food for thought.

EditDeleteKristin has covered this well. I would add that it is both important to keep your lower layers relatively lean and not slick and to make sure that there is sufficient binder in the upper layers to follow correct layering practice and to provide the proper adhesion. You may need to add a bit of additional binder to your upper layers to counteract what you describe.