The general advice is to wait 6 – 12 months before varnishing an oil painting.
Specifically regarding regalrez based varnishes, Gamblin suggests that a painting can be varnished with Gamvar as soon as it is touch dry, which contradicts advice from George O’Hanlon and Virgil Elliot.
What I would like to know is, what are the consequences of varnishing too early with a regalrez based varnish?
Thanks Scott and Brian.
So in summary, the two main concerns are that the varnish will wrinkle or crack as the paint underneath is still expanding and contracting, and the varnish may become incorporated with the paint, making it more difficult to remove.
I imagine that the cracking/wrinkling would occur relatively quickly after varnishing? Something like within a month? (Unless the paint is very thick). I’m thinking this because the bulk of the volume change in curing paint happens at the beginning of the curing process.
I think the main problem here is that most artists I see misinterpret the instructions to be ‘touch dry’.
Scott, would the ‘hard dry’ test (or is it ‘through dry’), defined by the ASTM,, be useful here? If I remember correctly, you press your thumb into the paint and turn it 90 degrees. If there is no mark that can’t be buffed out, it is hard dry.
Yes, any cracking of the varnish layer would happen sooner rather than later – during the expansion and contraction of the paint layer underneath. We have never seen this or heard about this happening with Gamvar.
I have removed Gamvar off of many paintings, some many years old. Other paintings, I have removed the Gamvar varnish and reapplied it repeatedly. Unless the paint layer was underbound to begin with – and remains “open” – I don’t see Gamvar incorporating into the paint layers to the point of being problematic down the road.
Kind regards,
Scott Gellatly
Thanks Scott.
I am going to send Gamblin a note to see if they want to comment here. Perhaps they have done some definitive testing and I am in the wrong. For the moment, however, this is one of the only subjects where I disagree with the folks at Gamblin, and I do so for the following reasons: It is generally believed that early varnishing causes a similar situation to that of overpainting before the previous layer has had time to sufficiently oxidize. The upper layer can then set more firmly than that below it. Someone might say that the lower layer will oxidize over time even through the superimposed layer but we have ample examples of paint defects cause by artists overpainting too quickly, resulting in wrinkling and even alligator-skin like fissures. Likely a low molecular weight resin like Regalrez is likely less likely to allow oxygen to penetrate than even an oil layer.
There is also the notion of the creation of an interactive zone. It is generally thought that while oil paint is fresh, it is more receptive to absorbing additional layers. This is the counterpart to the concept that old oil paintings have a surface that is “closed” and layers applied at a much later time do not adhere very well. More germane here is the idea that if varnish is applied too soon it can partly incorporate itself into the oil film creating a layer that will be more sensitive to solvents.
Having written all of the above, I have to be honest, I do not know of any scientific studies that have proven or disproven these suppositions. Perhaps Gamblin has and I am way off base. Finally, this is one of the subjects that I hope to study when I get an artificial weathering instrument. I expect to have access to one in the next year.
To be clear, our recommendation states: “All Gamvar can be applied when the thickest areas of your painting are thoroughly dry and firm.”
The reason that we don’t conform to the “6 – 12 months” rule of thumb is an acknowledgment that this rcommendation doesn’t speak to how the painting was made and with what materials. Paintings done with fast-drying colors/mediums in thin layers are ready for varnishing sooner, whereas paintings made with slower drying colors/mediums in thick layers require longer dry times.
Let’s also consider that the reasoning for the original “6 – 12 months” recommendation came out of the poor qualities of dammar varnish – namely its brittleness and its formulation (and subsequent removal) with turpentine – which has twice the solvent strength as Gamsol (the solvent in Gamvar). Regalrez is more inherently flexible than dammar. Since Gamvar’s launch in the early 90’s, we have never had any reports of Gamvar cracking as a result of premature application.
Scott Gellatly | Product Manager | Gamblin Artists Colors
Thanks for the clarification Scott.
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