Retouch varnish?

GTO

I’ve never used retouch varnish before.  I’ve got some areas of a painting that are full from drying but other areas next to them where the paint hasn’t dried.  I’ve got some Damar Retouch varnish and I’m thinking of spraying the dry-er areas with some of that.  

Any things I should look out for in doing this?  Any risks with over spraying wet areas?  I figure since it’s retouch I should be able to paint right over the retouch varnish once the retouch varnish dries?

dencal

GTO

The worst that can happen is the wet paint binds to the retouch varnish, making it impossible to remove the varnish for cleaning. If in the long term the painting is subjected to temperatures below 40f then cracking may occur in the varnish and take the bound paint with it.

Retouch varnish has the same components as normal varnish, solvent and resin. Retouch just has a higher proportion of solvent making for a thinner resin coating.

Denis

Richard_P

Personally I wouldn't put any kind of varnish on if the painting isn't dry.

GTO

Thanks @dencal @Richard_P. I appreciate your help.  

tassieguy

I get impatient so I sometimes spray retouch varnish if oiling out might disturb the paint layer. As long as the area of concern is touch dry a light spray of retouch varnish won't bond with the paint. But if the paint is still wet enough to stick to your finger forget it.

It's probably better to wait until your painting is completely dry then oil out rather than use retouch varnish. That way there's no risk. But I need to get works finished for my shows and sometimes I can't wait to oil out. That's one of the reasons why I don't use clove oil. Things take ages to dry. (The other reason is I hate the smell) If you are not pressed to get work finished then it's probably better to wait but with experience you'll get a feel for whether retouch is ok or whether you need to wait a bit longer. 

GTO

Thanks @tassieguy.  I may try oiling out the area I am needing to work on.

donnchadh4

Yeah retouch varnish will definitely mess with wet oil paint, and would cause it to breakdown over time. Retouch can be added when the top layer of the paint is "touch dry".

GTO

Thanks @donnchadh4 for helping with this question.  I’ve never used retouch before.

donnchadh4

@GTO I've never used a spray one before, but I use Daler-Rowney retouch varnish. Retouch varnish allows the paint to breathe so it can dry property, but usually does have a solvent in it. I find it never looks like "proper" varnish, but it's great in the way you can paint over it.

UncleJr

Retouch in dry areas only by soft hand brushing.  I would wait until the other areas dry first.  I have sprayed an entire painting before but when entire painting was very dry to touch .  I did retouch dry areas by hand first waited 48 hours and then sprayed the whole painting and after spraying I dry brushed it to even out. 

Abstraction

Do you mean during painting or as a final varnish? Conservators are very cautionary about using retouch varnish during painting.

"As most varnishes available today are easily removable, it is not recommended to apply them between paint layers. While extremely thin layers of retouching varnish might not cause future problems, any paint applied atop retouching varnish will be more susceptible to delamination or damage caused during varnish removal (as is often done during conservation treatments). Application of successive coats of retouch varnish or interlayers of varnish and paint can also increase a paint film’s brittleness, again leading to potential adhesion problems and cracking."

Surface Coatings, Retouching Varnishes, and Oiling Out, MATERIALS INFORMATION and TECHNICAL RESOURCES for ARTISTS, University of Delaware. 

You can access the full document for more information, including varnish advice, issues and cautions around oiling out, alternatives etc:

https://www.artcons.udel.edu/mitra/Documents/MITRA_Varnishes.pdf

tassieguy

Good info there, @Abstraction. Thanks for the link. I've printed out a copy of the pdf.