The question of when to varnish often comes up. Here are some of my criteria for making this decision.
You need to varnish an acrylic painting if:
- You have thinned the acrylic with a lot of water. It will have lost some of its ability to stick, and could be wiped off with a wet cloth.
- If you have collaged with thin papers or delicate items like thin foils. You don't want edges that could be caught or torn.
- The painting will be hung in an environment with smoke or oils, such as a restaurant.
- You want an even sheen on the painting. I am fond of a high gloss varnish on top of an abstact or brightly coloured painting.
- I do NOT always varnish fabric on a collage. I check whether the varnish will significantly darken the fabric first. Some papers need to be tested this way too.
You need to varnish an oil painting if:
- The shine is uneven in a way that you do not like. This problem is more common with oils, since oil content in individual pigments or oil mediums can vary a lot.
- The painting will be hung in an environment with smoke or oils.
You need to protect a watercolour with a fixative only if it will not be hung behind glass. This is not very common. For a commissioned watercolour painting such as the one above, I assume that the client will be framing any unframed items behind glass.
And the single most important thing to know about varnishing is - do not keep stirring into it as it is drying or you risk making it go cloudy. Lay it down smoothly and if you missed a spot, let the first layer dry (3 hours minimum, or what the bottle says) and make sure you get that spot with a second layer of varnish.
Conclusion: I do not find it necessary to varnish every acrylic or oil painting. When I do, often I do two layers.
Hope this is helpful.
Excited that Creative Collage starts today!
Happy Painting All!