I make many of my own materials and while damar never daunted me, I was reluctant with regard to Regalrez. Damar is the traditional varnish but it has some problems with application and aging. The National Gallery of Art has developed a varnish using Regalrez, a synthetic resin. Gamblin markets a Regalrez varnish under the name Gamvar but the price is ridiculously high. Fortunately, the varnish components are somewhat readily obtainable. There’s a rubber component added to aid in elasticity and brushability. Also, a UV blocker may be easily added to the finished varnish.
I’ve used several other varnishes, both synthetic and natural. Golden’s MSA is perhaps the worst I’ve used and a damar/mastic blend was one of the best. Regalrez features a low molecular weight, low refractive index, clarity, and easy solubility should removal be necessary. The varnish can also be applied as soon as the painting is dry due to the weak solvent and the resin not cross-linking with the drying oil.
I happened to have a couple of empty Jack Daniel’s bottles for storing the prepared solution.
At the time of this writing, I’ve varnished a dozen or so paintings with this, some large and some small. It has a long open time that allows it to be brushed out evenly. Once dry, it has a nicely natural sheen without looking like a hazy plastic layer as so many other varnishes do.