Painting large scale reconstructions using simple solutions of retouching media is a very difficult task. The applied paint thickens and dries too fast, making it impossible to work wet-in-wet or to apply glazes evenly over large surfaces.
The use of slower evaporating solvents for simple solutions of Paraloid B72 or PVAc helps only to a limited degree. Shellsol 100 used as a solvent for retouching/inpainting media evaporates at the same rate as Dowanol PnP (1-propoxy-2-propanol) used in the Slow B72 Retouching Gels. It is however easier to work with the Gels than with media based on simple solutions. The liquid crystal B72 Retouching Gels thicken more slowly as they tend to retain solvent for longer.