Retouch varnish

 

Retouch Varnish

Here is an edited version of an email exchange I had with an oil painter who had some questions about some oil techniques she is using and the main issue concerned the use of RETOUCH VARNISH.  She is concerned about permanence in her work and wanted to make sure she was using the retouch varnish correctly.  This is a topic I have not discussed so far in this magazine and I know it is one that many oil painters have questions about. 

Dear David,

I have been trying to get a scientific answer to the following question for some time. So far all I have is guesses, logical assumptions and refusals of help from some art suppliers because I don't deal with them. I recently read your gesso and primer advice you gave
in the FCA's "Art Avenue" under "Art Techniques" and immediately thought: "I may have finally found the guy to answer my question".  My question is: Can you, or should you, apply a retouch or final varnish over imitation gold leaf once the gold leaf
has been covered by a satin sealer?  I have combined oil and imitation gold leaf on canvas. These are the steps I have taken:
1. applied gold leaf adhesive onto gessoed canvas.
2. Placed the imitation gold leaf on the desired areas.
3. Completed the painting with oil around the gold leaf.
4. Applied a satin sealer to the gold leaf areas.

Now the painting is dry to the touch and I want to apply a retouch varnish to it.  Should the application of the retouch varnish include the gold leaf area or should I isolate the gold leaf and varnish the oil only?  The reason I apply a retouch varnish to an oil painting once it is dry to the touch, is to protect it from dust, smoke, and other air pollutants until, once is it completely dry (6mos.-1yr.), I can apply a final varnish.  During the retouch varnish stage, I can still go back into the painting and make new marks but once the final varnish has been applied, I have agreed with myself that the work is finished.

I would be thrilled if you could give me some straight answers on this - if you need more information please don't hesitate to email me.  Thanks in advance for any advice you may be able to give.

Regards, Lesley

Hi Lesley,

Here is a straight answer your question:  you should not put a retouch varnish on the gold leaf.  The sealer you describe is probably enough to serve as a protective varnish type layer over the gold leaf. 

Retouch varnish is a thinned out version of a final picture varnish used to 'bring up' dull areas of the painting where the color has sunken so that you can continue working on a surface with even sheen.  Typically, the picture varnish is diluted approximately 1:1 with a solvent like turpentine to make a retouch varnish.  You may have noticed when working with oils that some colors dry to a more matt finish than others and this variation of sheen between different areas of the image sometimes makes it difficult for painters to gauge values and hues when they resume work.  This is esp. important for portrait painters or those doing subtle transitions of tone and color.  Retouch varnish is meant to be used for this purpose only, not to keep the painting clean.  It should be applied very thin so that it does not form a resinous, continuous layer as this would add a complicated element to the structure of the painting and affect drying.  Also, the retouch varnish should only be painted over once it is completely dry. 

I would not be concerned about protecting the painting from pollutants over such a short period, unless you live in an unusually polluted environment in which case I would be more concerned about your own permanence!  Instead, continue to rework the oil painting for as long as you need to and if you like and when it is completely dry you can clean it gently with mineral spirits and a soft rag to remove any dust or grime before applying the final picture varnish. 

Hope that helps Lesley.  Cheers, David