History and characteristics
Amber was used by the Flemish masters in the 15th and 16th centuries.
This would explains why their work remains in such a fine state of preservation.
Because of it's hardness, brilliance and unique color, amber is regarded as the most beautiful and the
most reliable of all resin substances.
When dissolved, amber combines with oil (which becomes its medium).
It then becomes a fatty and elastic material that does not decompose.
Once it has hardened, it becomes a plastic that is neither brittle or friable.
Its color does not change and it dries slowly. Varnishes made with amber, mixed with oils in every concentration or used pure as a varnish, have a reflecting effect on the colors, making them seem finer, more transparent, more brilliant,
and more intense all at the same time.
According to the " paint thin, then fat " principle, it is not necessary to use
amber varnish in the first layers. It is recommended that amber solutions be used
with either linseed or poppy seed oils in subsequent layers, increasing the
amber concentration as the layers build up. For pictures that are painted straight-off
(al fresco) amber varnish can be used directly with the colors. Note that when amber
varnish is applied directly to unprepared panels, it makes an excellent painting ground.
For the artists who use dissolved amber as a medium, whether it's mixing it directly
with color or using the medium, there is no need to varnish the finished work.
The amber incorporated in the painting has already done this. Color " wrapped " in a
resinous substance will maintain it's integrity far longer than one that is unprotected.
Pure oil paintings can be varnished with amber as soon as the paint is dry enought that the brush
will not cause damage to the surface film. Once hardened, an amber varnish will not wear
away or need to be devarnished. Finally, a picture either painted or varnished with amber
can be worked over without risk since it becomes, in its hardened state, impervious to solvents.