How to protect the underpainting from smudging?

Question from Susan

How do you protect the underpainting from being absorbed or altered when rubbing off the brush strokes?

I am starting to paint again after many years, and remembering what I learned in school is tough. Thank you for being here to assist! I may eventually take some classes to help develop my technique and create interesting paintings that last. I do not always do classic prep, but when I do I refer to Web Art Academy.

Thank you so much.
Susan

Answer from Vladimir London, Drawing Academy Tutor

Dear Susan,

As I understand it, you are having some challenges in oil painting with protecting the under-painting from smudging.

The traditional multi-layer oil painting approach requires the under-painting to be completely dry before you continue with other layers. If you do under-painting in oil, it should give a very durable layer.

Sometimes, when using too much turpentine, the binding medium of oil-based paint can become so diluted that even dry paint can be smudged. If this is what happens with your painting, you may reduce the amount of turpentine you use or add a bit of linseed oil into the mix.

In regard to your comment on absorbing, I think you meant the that diluting medium is absorbed by the ground, which makes the colors dull. If this is what is happening when you paint, you can oil-in dull areas with linseed oil before continuing with subsequent layers. Various grounds have different degrees of absorbency, so you could experiment with gesso to achieve the results you want.

You will find more information on the importance and technique of underpainting in the “Why Old Masters Did Under-painting” video presentation, created by Natalie Richy, the Web Art Academy Founder andTtutor.

I hope I have understood your questions correctly; if not, please provide more details on what grounds, paints and mediums you are using. I will be happy to help.

Kind regards,

Vladimir London
Drawing Academy Founder and Tutor