Grumbacher Oil Medium: Picture Retouch Varnish 74ml

Grumbacher Picture Retouch Varnish is a temporary, clear, and glossy medium used during the intermediate stages of an oil painting. Its purpose is to even out the sheen of unfinished work, revive dull colors in "sunken-in" areas, and protect the painting from dust until a final varnish can be applied.
How to use
Work on a dry-to-the-touch painting. Wait until the paint film is completely dry before applying. Applying too early may smear wet paint.
Work in a well-ventilated area. The varnish contains flammable ingredients and vapors that can cause drowsiness and allergic reactions. Use outdoors or in a space with adequate ventilation.
Apply a very thin coat. Use a soft brush to apply a single, light, even coat. A thin layer ensures it dries quickly and remains reworkable. If the coat produces a prominent gloss, you have applied too much.
Wait for it to dry completely. Before painting over, ensure the varnish has dried completely.
Use it for temporary protection. You can use this varnish to protect your artwork from dust and scuffing for several months until the painting is fully cured and ready for a permanent final varnish.