DOI article:
Thomas Manly, Perfected Gelatine Ozotype
DOI Page / Citation link:https://doi.org/10.11588/diglit.30574#0053
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the bichromates would be more easily reduced than chromic acid, and the
copper would be more easily converted into a chromate.
There are many combinations of acetic acid, copper, and hydroqui-
none which will yield excellent results and it has been a very difficult matter
to select one particular formula for distinct recommendation, but I have
found the following a good all-round bath: First make up a 20 per cent.
solution of Sulphate of Copper, thus:
Water.20 ounces
Pure sulphate of copper.4 “
The water should be warmed, and the crystals suspended in a muslin
bag just under the surface of the water; dissolution will then take place in
about fifteen minutes. As this solution keeps indefinitely, a fair quantity
can be made up at a time.
CONCENTRATED ACID OR REDUCING SOLUTION.
20% solution sulphate of copper.
Glacial acetic acid ....
Glycerine.
" " 2 "
" " 2 "
WORKING ACID BATHS.
A
B
C
as above .
. 2 drams
. 4 drams
. 6 drams
Water.
. . 40 oz.
A will produce a strong picture from a weakly printed proof; B will
These baths will produce a picture from a correctly printed initial image
A Word to Beginners.— In some countries outside England, various
49
A will produce a strong picture from a weakly printed proof; B will
produce a medium picture from a medium printed proof; C will produce a
delicate picture from a strongly printed proof.
These baths will produce a picture from a correctly printed initial image
in half an hour to one hour after squeegeeing.
Development.—It is advisable not to separate the plaster backing until
the corner seems fairly easy to pull off5 especially when large sheets are being
worked. When the backing is off keep the print face downward on the
surface of the water, and move it about so as to assist the dissolution of the
soluble gelatine. The mug may be used after this, if found necessary.
Brush-work should be done with care. The best brush to use is a very soft
Siberian mop-brush, as it holds more water than an ordinary camelVhair
brush. Always keep the brush well saturated with water, and it is well,
sometimes, to perform the brush-work while the print is being held under
the surface of the bath. When manipulating light clouds the brush may,
with advantage, be dipped in cold water.
A Word to Beginners.— In some countries outside England, various
writers upon the ozotype process give a formula for the sensitizing solution
carelessly copied from an old specification. I would warn beginners to
beware of employing this formula. Like everything else connected with
ozotype, the sensitizing solution has been immensely improved, with the
result that the sensitive surface keeps much longer, the insolubilization of the
gelatine is stronger, precautions have been taken to prevent the solution
49
copper would be more easily converted into a chromate.
There are many combinations of acetic acid, copper, and hydroqui-
none which will yield excellent results and it has been a very difficult matter
to select one particular formula for distinct recommendation, but I have
found the following a good all-round bath: First make up a 20 per cent.
solution of Sulphate of Copper, thus:
Water.20 ounces
Pure sulphate of copper.4 “
The water should be warmed, and the crystals suspended in a muslin
bag just under the surface of the water; dissolution will then take place in
about fifteen minutes. As this solution keeps indefinitely, a fair quantity
can be made up at a time.
CONCENTRATED ACID OR REDUCING SOLUTION.
20% solution sulphate of copper.
Glacial acetic acid ....
Glycerine.
" " 2 "
" " 2 "
WORKING ACID BATHS.
A
B
C
as above .
. 2 drams
. 4 drams
. 6 drams
Water.
. . 40 oz.
A will produce a strong picture from a weakly printed proof; B will
These baths will produce a picture from a correctly printed initial image
A Word to Beginners.— In some countries outside England, various
49
A will produce a strong picture from a weakly printed proof; B will
produce a medium picture from a medium printed proof; C will produce a
delicate picture from a strongly printed proof.
These baths will produce a picture from a correctly printed initial image
in half an hour to one hour after squeegeeing.
Development.—It is advisable not to separate the plaster backing until
the corner seems fairly easy to pull off5 especially when large sheets are being
worked. When the backing is off keep the print face downward on the
surface of the water, and move it about so as to assist the dissolution of the
soluble gelatine. The mug may be used after this, if found necessary.
Brush-work should be done with care. The best brush to use is a very soft
Siberian mop-brush, as it holds more water than an ordinary camelVhair
brush. Always keep the brush well saturated with water, and it is well,
sometimes, to perform the brush-work while the print is being held under
the surface of the bath. When manipulating light clouds the brush may,
with advantage, be dipped in cold water.
A Word to Beginners.— In some countries outside England, various
writers upon the ozotype process give a formula for the sensitizing solution
carelessly copied from an old specification. I would warn beginners to
beware of employing this formula. Like everything else connected with
ozotype, the sensitizing solution has been immensely improved, with the
result that the sensitive surface keeps much longer, the insolubilization of the
gelatine is stronger, precautions have been taken to prevent the solution
49
