DOI Page / Citation link:
https://doi.org/10.11588/diglit.19571#0181
THE ARTIST'S ASSISTANT. 167
by any flight ftrok.es; and it will not well bear anv
polifli, but may be brought to a very fmooth furfacc
without, if it be judicioufly managed in the laying it
on. It is likewife lomewhat tedious in drying, and
will require fome time where feveral coats are laid
on, as the laft ought not to contain much oil of tur-
pentine. It muft be obferved likewife, that the gum
refin. fuch as the animi, copal, &c. can never be dii-
folved in fubftantial oils, by the medium of heat,,
without a confiderable change in the colour of the
oils, by the degree of heat neceffary to produce the
folution. A method of diffolving gum copal in oil
of turpentine is, however, now difcovered by agen-
tleman of great abilities in chemiftry ; and he has
alfo obtained a method of diffolving amber in the
fame menftruum, fo that we may hope foon to fee the
art of japanning carried to a confummate degree of
perfection ; when the public are putin poffeffion of
thefe moft important inventions, or the fruits of
them.
Of blue japan grounds.—Blue japan grounds may-
be formed of bright Pruflian blue, or of verditer
glazed over by Pruflian blue, or of fmalt. The co-
lour may be beft mixed with fhell-lac varnifh, and
brought to a polifhing ftate by five or fix coats of
varnifh of feed-lac. But the varnifh, neverthelefs,
will fomewhat injure the colour, by giving to a.
true blue a call of green ; and fouling, in fome de-
gree, a warm blue, by the yellow it contains. Where,
therefore, a bright blue is required, and a lefs de-
gree of hardnefs can be difpenfed with, the method
before directed, in the cafe of white grounds, muft
be purfued.
Of
by any flight ftrok.es; and it will not well bear anv
polifli, but may be brought to a very fmooth furfacc
without, if it be judicioufly managed in the laying it
on. It is likewife lomewhat tedious in drying, and
will require fome time where feveral coats are laid
on, as the laft ought not to contain much oil of tur-
pentine. It muft be obferved likewife, that the gum
refin. fuch as the animi, copal, &c. can never be dii-
folved in fubftantial oils, by the medium of heat,,
without a confiderable change in the colour of the
oils, by the degree of heat neceffary to produce the
folution. A method of diffolving gum copal in oil
of turpentine is, however, now difcovered by agen-
tleman of great abilities in chemiftry ; and he has
alfo obtained a method of diffolving amber in the
fame menftruum, fo that we may hope foon to fee the
art of japanning carried to a confummate degree of
perfection ; when the public are putin poffeffion of
thefe moft important inventions, or the fruits of
them.
Of blue japan grounds.—Blue japan grounds may-
be formed of bright Pruflian blue, or of verditer
glazed over by Pruflian blue, or of fmalt. The co-
lour may be beft mixed with fhell-lac varnifh, and
brought to a polifhing ftate by five or fix coats of
varnifh of feed-lac. But the varnifh, neverthelefs,
will fomewhat injure the colour, by giving to a.
true blue a call of green ; and fouling, in fome de-
gree, a warm blue, by the yellow it contains. Where,
therefore, a bright blue is required, and a lefs de-
gree of hardnefs can be difpenfed with, the method
before directed, in the cafe of white grounds, muft
be purfued.
Of