A water colour painting is usually
framed behind glass and therefore does not need to be varnished.
The glass protects the water colour against dirt and somewhat
against the harmful effects of light on the colours.
If, however, a water colour painting has to pass from hand to hand
for illustrative purposes it can get damaged by dirt and moisture.
In this case it would be best to varnish the painting. Talens Water
Colour Varnish Matt 050 is invisible after drying and makes the
water colour resistant to water. The paint is now protected against
moisture and it may be possible to remove dirt. The varnish can
also be used for water colour pencils.
One of the specific characteristics
of a pastel painting is its velvety look. By fixing the painting
this appearance will change, depending on the amount of fixative
used. If too much fixative is used the colours may become darker
but even then the painting will not be resistant to smudging. So
take care!
In order to retain the specific look of the pastel painting some
artists do not fix their work at all and so are prepared to put up
with the resulting vulnerability. A safer manner is to fix the
painting lightly between layers. It is up to the artist whether the
final layer is fixed.
On the other hand, there are other artists who do varnish their
pastel paintings quite heavily and take account of the darker
colours. This, of course, requires experience.
The lead of a coloured pencil is made
of pigment, kaolin (a fine clay), wax and cellulose. The wax
ensures for the characteristic creamy colour transfer of the pencil
and makes the colours resistant to water. At the same time,
however, the wax has the tendency to form a white film on the
paper. This film disappears when a thin layer of concentrated
fixative is applied. The more fixative, the glossier the result. If
a matt finish is required, matt acrylic varnish can be used. A
fixative can also be used to protect the drawing from
smudging.