Janet Kaiser on sat 6 sep 03
Linda, my short answer would be to go for a walk in a pine forest
near you and look for injured trees. You will see the ouzing sap
and can scrape it off quite easily. I have only encountered
commercially produced resins (or gums as they are also called) as
a painter, except for gum arabic which I played around with a
couple of raku glazes and again when experimenting with resist
techniques, when I actually found that boiled flour and water was
much cheaper and just as effective for my needs! However to help
you possibly find alternatives to "pine tar", I quote the
following from:
The Materials and Techniques of Painting
by Jonathan Stephenson
Thames and Hudson, 1989
RESINS:
Resin is the hard, glassy substance that remains once the natural
solvent passes off from the thick, sticky, sap-like product
secreted by certain trees. Resins will not dissolve in water, but
they will dissolve either in organic solvents or in drying oils.
Prepared in this way they are used in varnishes, painting media
and paints, and certain resins may also be combined with waxes
for encaustic painting. As varnishes, their function is to
provide a transparent protective layer, while in paints and
painting media they can improve the gloss or clarity of the paint
film and reduce the colour of the medium. They are also used to
increase the durability of the finish, to add body to drying oils
and to reduce drying times. The suitability of particular resins
for particular purposes varies considerably. Resins may be
separated into hard and soft varieties.
DAMAR RESIN
Damar resin occurs in irregular lumps which on average are the
size of a hazelnut or small peach stone, though much bigger
pieces are not uncommon. They have a white, powdery surface, but
when broken open reveal a clear interior of very pale yellow
colour. The lumps break and crush easily, and frequently contain
particles of bark and similar impurities. This is considered the
best natural resin for use in painting because it has very little
colour and ages well. Damar dissolves in turpentine to produce a
removable varnish, also suitable as a retouching varnish, which
is unlikely to crack or bloom. In this state it may also be
blended with oils or added to temperas. Damar has a low melting
point for a resin and may be blended directly with oils or wax by
applying heat.
MASTIC
Mastic resin is made up of small drop-like lumps, often referred
to as mastic tears. These have a thin covering of whitish dust,
but the yellow colour of the resin remains clearly visible and
inside, the mastic tears are clear but quite strongly coloured.
It was at one time an important artists`material, but is now
considered inferior to damar and is expensive. Mastic behaves in
much the same way ad damar and can be used for similar purposes.
As a varnish, mastic produces a warm yellow glow, which has a
mellowing effect on paintings and may be used deliberately to
harmonise and subdue colouring. It is prone to cracking and
further discolouration, however, and may occasionally bloom. When
combined with a drying oil that has been boiled with lead, mastic
produces a jelly-like substance called megilp, which can be used
as a painting medium, particularly in impasto techniques,
Although interesting to use, in the long term it cannot be
regarded as stable.
AMBER AND COPAL
Amber is a semi-precious stone which is actually a fossilised
resin. It was an ingredient in early oil media and has acquired
an almost legendary reputation, Copals are a family of similar
resins, some of which are also fossilised. These resins will only
dissolve in hot oil. They produce oil varnishes which are dark in
colour with considerable body: when dry they form a glossy, hard
surface which is highly resistant to the atmosphere. Since they
cannot be removed with ordinary solvents, they should not be used
as a final varnish. They many be used in paints and painting
media if they are of a sufficiently high quality, but should be
employed cautiously if your are to obtain good results, as the
strong colour of these materials can affect pigments from the
outset and copals in particular are inclined to darken later.
Manilla Copal is the most easily obtainable resin of this type.
It is not unlike damar to look at, but the lumps are more angular
and there is a greater variety of size and colouring amongst the
pieces. Manilla copal produces a thick, black oil varnish which
is a warm brownish orange when thinned down. Although it is a
difficult process, painters will obtain the best results if they
prepare resin oil vehicles of this kind for themselves.
GUMS:
Gums are extracted from plants. Like resins, they begin as a
sap-like substance which gardens on exposure to the air. The
difference is that gums dissolve in water while being insoluble
in oils or organic solvents. They are used in solution with
water; this solution dries by evaporation, leaving a deposit of
gum in an unaltered state, which remains permanently soluble in
water. Like all solvent media, gum solutions lose volume as they
dry and do not retain brushmarks or impasto effects. They are
brittle and inflexible and with crack if applied too thickly of
if used on an unsuitable support.. Gums adhere best to a lean
surface. They can be emulsified with oils and resins, or
intermixed with tempera and acrylic media.
GUM ARABIC
The most important gum is gum arabic, which his produced by a
species of acacia and is sometimes referred to as gum acacia. In
its raw state it takes the form of glassy angular lumps which
vary in colour from water white to shaded of red and brown. Small
pieces of woody matter are usually mixed in with the raw gum as
well. For ease of use it is often supplied as a powder, which is
an off-white; the nearer it is to true white, the better the
quality. The best way to assess the quality of gum arabic is to
make some into solution. The finest gum produces an almost clear
solution of a very light brown colour... (snip)
Gum arabic is used as a binding medium for watercolour and
gouache paints and for pastels. It can also be employed as a
painting medium and as a selective varnish. Other applications
include use as a paper glue, as an addition to temperas and as a
main ingredient in gum tempera, where it is emulsified with a
drying oil. An addition of glycerine, honey or sugar is
frequently made to render gum arabic less brittle and a
preservative is necessary if the gum solution is to be stored for
any length of time. If left to stand, some grades will deposit a
brown mucus at the bottom of their container and the quality of
the solution above will steadily improve.
GUM TRAGACANTH
Is an expensive material... (so will not type that out)
OTHER GUMS
pAINTERS ARE OCCASIONALLY REFERRED TO OTHER GUMS: gUM AMMONIAC IS
AN OBSURE; AROMATIC GUM RESIN WHICH IS USED IN WATERBASDED GOLD
SIZE FOR GILDING IN MANUSCRIPT ILLUMINATION. (oohps sorry, CAPS
stuck) Cherry gum refers generally to gums obtained from fruit
trees, such as cherry, plum and apricot, Gum lac and gum edere
are defunct pigments. The only other product of any significance
is dextrin, which is an artificial gum produced from starch, now
used as a cheap alternative to gum arabic where fine quality is
unimportant.
It is trade practice to refer to both gums and resins as gums.
Gum damar, gum mastic and gum copal should be understood to mean
the resins of the same name. (end of quote).
Hope this helps!
Sincerely
Janet Kaiser
*** IN REPLY TO THE FOLLOWING MAIL:
*** From: Linda Knapp
*** E-address: linda@BOZUK.ORG
*** Sent: 04/09/2003 Time: 23:00
>I am experimenting with Lusters and making my own - (after the
sticker
>shock of buying some!) I have managed to assemble a variety of
the
>needed ingredients for a copper resin luster.
*** THE MAIL FROM Linda Knapp ENDS HERE ***
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