THE PHOTOGRAPHIC NEWS, April 12, 1861, p.171

PRINTING ON IVORY.

THIS department of the art of photography is one that of necessity conies more under the notice of the professional photographer than the amateur, as prints on ivory have) until, they have been under the pencil of the miniature painter, no especial feature which renders them of particular value.

The first desideratum, and one in which it is necessary great caution should be used, is the selection of the plates of ivory. There are now in the market two kinds, presenting very different appearances. The first is that which is well known as leaf ivory, and is cut across the grain of the tooth, according to the size of which it displays more or less of what are technically known as mackerel marks, which are much more strongly developed in some plates than others. But care should be taken to choose cuts from the centre of the tooth, where there is a considerable space without these marks, which on printing the picture come out very strongly, and when they happen to strike across the face of a miniature can scarcely be overcome by the painter. The second kind of ivory is that known as twist ivory, and is so called from its being cut by a saw working vertically, whilst the tooth or tusk is pressed hard against it at an acute angle; the result is, that, by the tooth being made to revolve, a sheet of ivory is obtained, far larger than can be cut transversely from even the largest teeth, and possessing also the important advantage of having no grain or mackerel mark in it. But there is another side of the question; this ivory is so much more expensive than the other, that where only small pictures, say not more than 3¼ by 4½, are to be produced, few would incline to pay the price, and for my own part, where the opportunity of selection is at hand, I should choose those pieces of the ordinary leaf ivory, which have the broadest space in the middle without grain; these plates should have one side smoothed, till all saw, marks are obliterated, and the surface is as polished as a, piece of writing paper, and all pieces not in this state should be rejected, although by means of fine emery a very near approach may be made to it. Having chosen the plates of ivory, the next step is to bring the, prepared surface into a proper condition to receive the impression, and which is thus accomplished. Prepare a mixture thus:--

Let the mixture be most diligently agitated by a whisk until it is all froth. Now put aside, and allow it to settle down, when it may be decanted for future use, as the ammonia will preserve the mixture from decomposition, and it will improve with age, until three or four months old; to use this solution take a good rigid camel-hair brush, I prefer a flat one, half-an-inch wide, and lay the albumen carefully over the, smooth side of the ivory, taking care to pass the brush in the direction of the grain, and straight down only, not up and down; when the surface is quite smooth put it aside to dry on the back, out of the way of dust, and, if possible, in a room of which the temperature is not lower than 70° or 80° Fahrenheit, as the albumen at this heat dries on the surface, and is less troublesome at a subsequent part of the process. These plates should be wrapped up when done, each in a separate piece of tissue paper, to avoid scratches. When a picture is to be printed, float a sheet of ivory on a small quantity of eighty-grain solution of nitrate of silver. It is of great importance to be quick in placing it on, as the plate curls up instantly, and if it have not touched the fluid all over, or if there are bubbles under it, it is very probable that, in attempting to rectify this, that the solution will get on the back of the plate, and thereby cause marks of more intense action in the picture at the parts over the spots.

The sensitizing should always be done in the dark room, as the action of light on the animal substance of the ivory when covered with the surface of the chloride of silver, is far more rapid than on paper, either albumenized or plain salted.

When the floating has continued for three minutes, remove the plate with horn pincers, and set it up on end to drain for a few minutes on a piece of bibulous paper, which done, lay it on its back in a drawer or cupboard to dry, meanwhile preparing the negative for producing its print in the following manner: the great distinction between printing on paper and on ivory is in the fact, that the former, when in the pressure-frame allows the progress of the picture to be inspected by bending in the middle; whilst the latter being rigid cannot be so treated. It is, therefore, necessary to take a piece of white note-paper, the size of the negative plate, gum one end of it a quarter of an inch deep, stick that end at the back of the lower part of the negative, then turn the paper round to the face of the negative.

Now take the plate of ivory and place at each corner of the back a touch" of gum, then lay it on the face of the negative in its right place, and turn the piece of paper, already in place; down over it. the gum at the corners of the ivory will adhere to the paper, and it can now be all put in the pressure-frame together. As I just noticed, the printing is very rapid, and should have great attention, and the frame never be opened but in the yellow-room, or all the finest tones are soon lost.

To see the progress of printing it may be taken quite out of the frame; as the paper keeps the ivory in position.

The over-printing should be considerable, as in the subsequent processes it is often the case that much reduction is made in the intensity of the picture.

The picture, as we may now call our production, being removed from the frame, wash it in running water for ton minutes; rubbing it carefully on the surface with the finger, when it will be found that the whole of the albumen will rub off as a powder, leaving the picture on the very surface of the ivory, and with the pure face of that beautiful material unsullied. I know very well that at this point the practical photographer will exclaim. "but albumen is rendered insoluble by contact with nitrate of silver, and cannot be removed;" so thought I, but it will be found that there is no difficulty whatever in rubbing it off under a stream of water, and the plate may then be transferred to a fixing bath of gold as usual for paper.; but as the picture. when painted, will be of considerable value, it is of vital importance that the bath be strong of gold and hypo, and by no means acid. About ten minutes is sufficient to produce a good colour, and one well suited for painting on. I find that generally preferred is a purple or dark sepia tone; rather than black, which often presents great difficulty to the painter in fair complexions. Now remove the plate to a bath of strong new hypo for ten minutes, and thence to running water, in which it should be rubbed with a sponge for the first ten minutes; directing the stream full on the plate. It should be left to wash in this stream of water for twelve hours; and then taken out and dried with a silk handkerchief.

It is now more than likely that on placing the picture on apiece of card it will be found too dark for painting, in fact, it is as well it should be so, for by the next process the tone can be regulated with such exactness that it is unimportant how dark it now looks.

Prepare a weak solution of cyanide of potash, say 5 grains to the ounce of water. and use it for no other purpose than the one now to be indicated, and above all things avoid using it for dissolving the iodide of silver from negatives, the result being that the solution becomes charged with cyanide of silver, and utterly destroys the ivory picture in a very short time. Now take a camel-hair brush and go carefully and very rapidly over the background of the picture with this mixture, working carefully round the hair, and it will at once be seen the colour is giving way under the cyanide, continue this treatment until the whole or nearly all of the background is gone, and the ivory left as clear and white as-before any chemical: operation was commenced on it, on this the painter, of course supposing he possesses the requisite talent, can produce those lovely effects for which ivory is unsurpassed by any known material. Now with the same solution" go rapidly all over every part of the picture which requires to be made lighter, and By having a brush at the other end of the pencil dipped in water the action may be moderated to any extent. By this means, in skilful hands, and after a little practice, excellent effects may be obtained--heavy sombre shadows removed. a frowning forehead made more cheerful, high light judiciously thrown, leaving the clear surface of the ivory covered only with a delicate tint on which the painter can by transparent colours give the finest of flesh tints, and all that play ,of colour which the artistic eye perceives in the human countenance, with a force, vigour, and correctness to-nature, such as can rarely if ever be approached by means of any other medium. When the cyanide has played its part, wash for five minutes under running water, and from its complete and ready solubility the removal is easily effected.

It will be perceived long eve this by my reader, who is au fait at-photographic processes, and in the habit of drawing inferences therefrom, that the two main principles involved in the process I have described are, first- the supporting the picture on the surface of albumen which having fulfilled its object, is removed; and, secondly, the production of any required depth of picture, and the clear background; by means of the cyanide-of potassium.

Were the albumen omitted, the solutions would sink into the plate, and the result he most unsatisfactory; and, on the other hand; it is seldom that without the use of the cyanide the exact tone is produced; from the fact of the ivory drying up, several shades darker than it appeared when wet, as a plate of ivory when thoroughly soaked in water is very transparent. I am also inclined to believe that a picture; which has been under the action of cyanide is more securely fixed than when it has been under hypo only; but- it is necessary that most copious washing be given to the picture between the operations, or stains are produced by the mutual action of the two chemicals. It will not be a matter of the smallest surprise to me to learn, on the publication of this process, that some one else has also discovered it; but I have never at any time either reader had described: to me any process, either in detail or in part, which had for its object the production of a photograph on ivory; and though repeated requests have been printed in the journals for information, no reply of any kind has to my knowledge been given.

It is far from impossible that those engaged in the production of photographs on ivory as a professional affair may raise objections to parts of my process; but my answer to such would be the good results obtained.

In conclusion, if I have been prolix tedious in my description it arises from a wish to give the fullest instruction on every detail of the process; and those in the habit of trying new processes will readily forgive the writer for his errors in this direction.