Repainting Over Acrylics

 

Repainting Over Acrylics

Dear David,

I was just reading the September-October edition of Art Avenue. Robert Genn's advice about "Dealing with Dogs", (i.e. old paintings that don't work) is great, but I am wondering if there is any way to go back and re-work acrylics when they have already been given their "final coat" of acrylic varnish.  I use a gloss medium when I am painting, so when I finish a piece I give it a coat of gloss acrylic varnish. I find that this evens things out and gives me a final "look" that I like.
The two products that I am currently using are:

a)  Mixed with water as a painting medium: Opus brand Gloss Polymer Medium.
b)  As a final varnish: Acrilex Gloss Varnish.

The problem comes several months later when I look back at what I thought was a finished painting and realize that it could benefit by some reworking. My understanding is that once the varnish is down the paint won't adhere properly. Am I correct in thinking this?  Do you think it is safe to make the changes or should I use the mineral spirits to remove the varnish first? Is there any way to
get around the problem?

Thanks for your help, Moira

Hi Moira,

You say you use a gloss medium throughout the painting, then a "gloss acrylic varnish" at the end.  If so, it is not really a final picture varnish (it would be considered an 'isolation' varnish) and you can go ahead and make changes.  If it is actually an acrylic solution picture varnish then you would first need to remove it using mineral spirits before repainting.

Acrylic paint will not adhere well to an acrylic solution picture varnish but I think you are probably using a water based medium - I don't think Acrilex makes an acrylic solution varnish.  It is most likely just an acrylic polymer (water based) medium/varnish like the Opus brand medium you use.  Sometimes acrylic mediums are labelled medium/varnish because they can be used as an isolation varnish when the painting is completed, like what you are already doing.  If it is a solvent based solution varnish you would certainly notice the smell and you wouldn't be able to clean your brushes with water if it was solvent based.  It should say on the jar however.  Go ahead and make your changes unless you are convinced the Acrilex it is a solvent based varnish. 

You can make changes and rework an acrylic painting at any time as long as you have not yet put a final Acrylic Solution Picture Varnish on it.  Liquitex Soluvar and Golden’s MSA varnishes are solvent based picture varnishes and are conservation quality.  I use them both for my acrylic and oil paintings. 

These acrylic solution varnishes must go on top of the ‘Isolation’ layer of acrylic gloss medium that you put on at the end of your paintings.  It is essential to put this isolation layer to protect the painting from coming into contact with the final picture varnish, which is solvent based.  Acrylic paint is sensitive to solvents and can easily be damaged by coming into contact with them.