What is "megilp"

Megilp \Me*gilp"\, Megilph \Me*gilph"\, n. (Paint.) A gelatinous compound of linseed oil and mastic varnish, used by artists as a vehicle for colors. [Written also magilp, and magilph.]

n. (context arts English) A medium for oil painting, consisting of linseed oil mixed with turpentine or mastic varnish.

n. a medium for oil-paints; linseed oil mixed with mastic varnish or turpentine [syn: megalp]

Megilp also known as Macgilp and McGuilpis is an oil painting medium consisting of a mixture of mastic varnish and an oil medium: such as walnut, linseed, safflower, poppy, black oil (linseed oil) cooked with litharge or white lead etc. Earlier recipes may omit the mastic and substitute wax The decorative painters' and glaziers' guide,

By Nathaniel Whittock 1828 p 27It makes oil paint thin, glossy, and easy to work, with an extremely short drying time; and depending on the formulation, the modern, premixed glazes may help produce the sensation of depth, and help the painter by producing transparency that will hold in place rather than running or sagging, while at the same time sidestepping many of the traditional problems associated with Megilp, seeing how the archival quality of the older recipes is much disputed. Some Mayer An artist handbook of materials and techniques, Fifth edition Page 225 1990
claim the traditional, hand mixed medium causes paint to become yellow and brittle, while others claim that improperly prepared paint is the cause and that the longevity of Megilp (especially in its premixed glazing form) is excellent.

Victoria Finlay cites Joshua Reynolds as an example of a painter whose reliance on megilp has detracted from the longevity of his paintings. Specifically, she indicates his painting Girl With a Baby as one which has changed a great deal over time. Megilp was also used by Turner.