Tracing Process On Metal
We call the attention of metal engravers to this process. It is well
known that wood engravers have their original designs photographed on the
block in order to save considerable time by not making the drawing
themselves; moreover the cost is nominal, so to say, and the copy more
true and perfect than it can be done by hand. Why should not the copper
engraver and the aquafortist avail themselves of the same advantages? A
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or, if so, not having tried it, think it is not possible or that it may
spoil their plates. This is an error. It can be done and very easily by
adhering to the following instructions:
Dissolve 2 parts of ammonium bichromate in 100 parts of water, and in this
let soak for an hour or so 10 parts of Coignet's best gelatine, then
dissolve on a water bath, filter through flannel, and the solution is
ready for use.
Before being coated, the plate should necessarily be cleaned free from
oxidation and greasy matters. This is done by immersing the plate for a
few moments in a warm solution of common potash, then rinsing and rubbing
it with chalk moistened with a little water, when after rinsing again and
draining the plate should be immediately prepared.
To spread the gelatine solution in an even and thin layer, a tournette is
employed. The most simple consists of a round wooden stick of which the
upper part is carved in the form of a cup with an edge, or rim, about one
quarter of an inch broad. On this rim is melted some gutta-percha, upon
which the plate is pressed into contact and adhers quite firmly when the
gutta-percha is solidified. The stick is perforated at the lower end and
revolves on an iron pivot fixed at the bottom of the support, being held
in the opening on the platform of the same, as shown in the diagram on the
following page.
The plate being fastened to the tournette, the warm gelatine solution is
flowed over it and spread to the edges by means of a glass rod or a piece
of cardboard, avoiding air bubbles. This done the tournette is set into
motion, and when the film is equalized, which is done in a moment, the
plate is detached, placed on a leveled stand and slowly dried with the
spirit lamp.
[A Tournette]
By a good light the exposure on the shade does not exceed twenty minutes
with a pretty intense transparency, and should be regulated with a
photometer. When the insulation is sufficient, the image is slightly
visible, and should be so. The plate is then bordered with banking wax
and bitten-in with a solution of ferric chloride at 45 deg. Baume, or--
Ferric chloride, crystal 20 parts
Hydrochloric acid 1 part
Water 100 parts
The parts of the gelatine film the most acted on are impermeable, so to
say, and consequently do not allow the etching fluid to penetrate to the
copper; while those the least impressed are permeated according as to
their degree of insolation, Therefore, when the ferric chloride solution
is poured upon the film and carefelly brushed over with a soft brush, in a
few moments the image progressively appears, the deep blacks first, then
the half tints, and lastly the most delicate details, the whole requiring
but a few minutes. It is now that the etching action should be stopped by
washing under the tap. However, should by excess of exposure, or any
other cause, the details not appear within five or six minutes, the ferric
chloride should nevertheless be washed off, for then it may find its way
under the film and the plate would be spoiled. After washing the gelatine
is dissolved in a solution of potash, etc., when the image would be found
slightly engraved.
Should the image be in half-tints, it would be advisable to apply a grain
of rosin on the gelatine film just before etching. To engrave on steel
the operations are the same, but on its removal from the printing frame
the plate should be soaked with water renewed several times until the
bichromate is washed off. The film is then dried spontaneously and
afterwards flowed for about two minutes with the Solution A, then, this
being thrown away, with the Solution B, which is allowed to act for a
similar period.
A. Nitric acid, pure 120 parts
Silver nitrate 6 parts
Alcohol, 95 deg 50 parts
Water 75 parts
B. Nitric acid, pure 5 parts
Alcohol, 95 deg 40 parts
Water 60 parts
More
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A Poitevin's Process 1870
"I use a paper prepared with iron sesquioxide rendered sensitive to light by tartaric or, better, citric acid in concentrated solution. This paper, after desiccation and exposure to light, possesses the property of reducing the solution of silver... Artigues' Process
The Artigues process, so called, is, without any doubt, the best to be employed for the reproduction of plans and drawings in lines. It is simple, expeditious, and yields black impressions on a very pure white ground which are absolutely permanen... Causes Of Failures
The images are veiled. This defect may result from various causes, viz.: 1st. The stock ferric oxalate solution is impaired by a partial reduction of the ferric salt into ferrous oxalate. The solution should be preserved in an o... Choice Of Paper Sizing
In all the photographic processes by precipitation of metallic oxides the quality of the paper has a great influence on the results. When the paper is not well sized and not well calendered, the sensitizing solution is absorbed, instead of simply ... Cj Burnett's Process 1857
"A capital process for many purposes," says Mr. Burnett, "is to float or steep the paper in a mixed solution of bichromate of potash and sulphate of copper, as for Hunt's chromotype process.(36) I have mixed gelatine, or occasionally grape sugar, ... De La Blanchere's Process 1858
Uranium nitrate 25 parts Distilled water 100 parts Filter the solution and keep it in the dark. The paper should be sized with a gelatine solution at 5 per 100 of water, and, when dry, kept in the dark.(40) It is sensitized by floating fi... Dr Jb Obernetter's Process 1863
Copper chloride 100 parts Ferric chloride, sol. sp. 13 parts gr. 1.5 Hydrochloric acid, conc. 12 parts C. P. Water 1,000 parts Float the paper on this solution for about two minutes and hang it up to dr... Dr Tl Phipson's Process 1861
Take a solution of perchloride of iron and, having precipitated the peroxide with ammonia, collect the precipitate on a filter and wash it with boiling water. Add the precipitate in excess to a warm solution of oxalic acid. A beautiful emerald g... Godefroy's Process 1858
Float the paper upon the following solution for three minutes and hang it up to dry: Uranium nitrate 30 to 60 parts Silver nitrate 8 parts Water 100 parts (39) The sensitiveness increases in proportion to the quantity of ... Graphotypy
This process consists in converting a cliche in half tones into one in lines, which can be directly printed on paper, or impressed, by means of an ink transfer made as explained before, on a stone, or on a zinc or copper plate for etching in relie... Guarbassi's Process 1867
The paper is floated in the dark for four or five minutes on a saturated solution of bichromate of potash. When dry, it is printed a little longer than for silver prints and afterwards floated, face upwards, on a water bath until all the unaltere... H Cooper's Process 1865
PREPARATION OF THE PAPER St. Vincent arrowroot 200 grains Boiling water 10 ounces Crush the arrowroot to fine powder, then rub it to a paste with a little water, and let an assistant pour a few drams of boiling water while you ... Houdoy's Process 1858
The paper is floated upon a lukewarm solution of gelatine at 5:100, and when dry, on a bath of uranium at 10 or 15 per 100 of water. After exposure to the sun the image is developed with a solution of silver nitrate acidified with acetic acid. T... How To Make A Negative Drawing
The drawing paper for designs to be reproduced by the cyantotype and the other processes described in this book should be of a fine texture, free from opacities and very white; and, as the design must serve as a cliche it is a sine qua non that it... L Liesegang's Process 1865
Pour ammonia into a nitrate of uranium solution, wash the precipitate of uranate of ammonia in distilled water, then dissolve in citric acid. Mix this solution of citrate of uranium and a little of a solution of chloride of gold with a paste pre... Niepce De St Victor's Process 1859
Red Prints. Float the paper for fifteen or twenty seconds on a 20 per cent. solution of nitrate of uranium and dry before the fire in the dark room. This paper can be prepared many days before use. Expose in sunshine from eight to ten minut... Preparation Of Red Yellow Or Blue Tissues
Red Tissue.--Dissolve 10 grams of carmine in 1 liter of aqueous ammonia and evaporate. When the smell of the alkali has almost disappeared, add 1 liter of rain water. Of this take 65 cubic centimeters, add 35 c.c.m. of rain water, and in the sol... Printing On Wood Canvas Opal And Transparencies
Printing on Wood.--To print on a wood block a design to be engraved on the same presents certain difficulties. In the first place, the sensitizing solution must not be absorbed by the wood, but remain wholly on its surface; then the photo film, a... The Aniline Process
The aniline process was published in 1865, by Mr. Willis, the inventor of the platinotype.(11) It is based on the oxidation of aniline by chromic acid, thus: A sheet of paper brushed with a solution of potassium bichromate and sulphuric acid, drie... The Black Or Ink Process Ferro-tannate Process
This process gives black positive impressions on white ground from positive cliches, and negative impressions from negative cliches. It has been attributed to Mr. Colas, but in reality it was invented by Mr. Poitevin, who describes it as follows ... The Carbon Process
The carbon tissue is seldom prepared by photographers. However, for the sake of completeness, we shall give the formula of the mixtures most generally employed, and describe the manner of coating the paper on a small scale. Preparation of the T... The Cuprotype Burnett's Process
This process gives positive impressions from negative cliches. Uranic nitrate 10 parts Cupric nitrate 2 parts Water 100 parts Float for a minute strong, well-sized paper on this solution and let it dry spontaneously in the dar... The Cyanofer Pellet's Process
This process gives blue impressions on a white ground from positive cliches, and white impressions on a blue ground from negative cliches. It is termed "positive ferrotype process." The cyanofer is an application of one of the numerous and usefu... The Cyanotype Or Blue Process
This process gives white impressions on a blue ground with diapositives or drawings on transparent or semi-transparent materials, and blue impressions on a white ground from negatives. It is commonly known under the names of "blue print process,"... The Platinotype
This process, discovered by William Willis,(16) yields very fine impressions which wholly consists of platinum and are, therefore, chemically permanent. It has been described theoretically and practically by Pizzighelli and Kuebl in a paper f... The Primuline Or Diazotype Process
Primuline, discovered in 1887 by Mr. A. G. Green, an English chemist, is a dye of a primrose color, possessing a great affinity for cotton fibers, to which it is readily fixed by simply immersing the material for a few moments in a hot solution of... The Uranotype
This process, devised by J. Wothly, in 1864, did not receive from the photographers the attention it merits, as it is always the case when a process is patented, and can be replaced by another equally practical which is not. It gives pictures of ... Tracing Process On Metal
We call the attention of metal engravers to this process. It is well known that wood engravers have their original designs photographed on the block in order to save considerable time by not making the drawing themselves; moreover the cost is nom... X's Process 1865 Secrets Of The Uranotype
Preparation of the Uranium Compound.--Precipitate the nitrate of uranium from its solution by concentrated liquid ammonia. Let settle the precipitate, decant, and wash in several changes of water. Dissolve it by heat in pure nitric acid, taking ...