Pre-exposure prophylaxis (or PrEP) is when people at very high risk for HIV take HIV medicines daily to lower their chances of getting infected. PrEP can stop HIV from taking hold and spreading throughout your body.
In the dry plaster or fresco secco technique, pigments are usually mixed with water, although other substances might also be used. The paint is then applied to a dry plaster wall which has been wetted down with water. Since the plaster is relatively dry, it is non-absorbent, and the pigment adheres to the surface of the plaster. This technique differs from true fresco (described below) in several ways. The colors tend to flake off the surface of the plaster.
Once dry, the wall can be painted, wallpapered and otherwise decorated as normal. While skim coating is often used to repair drywall, this process can also help treated areas that have already been painted. With a few extra steps you can create the right surface for a smooth skim coat.