Fig.27.
Fig.27.
It now remains to see which toning bath is to be used. If No. 1 or 3, the whole of the free silver should as far as possible be washed away, which may entail three or four changes of water; the last two washings it will hardly repay to place in the tub; the second washing should certainly be added to it. If No. 2 toning bath be used, a little free silver should remain in the print; in fact, the washing should be confined to two changes of water.
When toning operations are commenced, the toning solution is poured off from any sediment that may be in the bottle containing it into a dish a couple of inches wider each way than thelargest print which has to be toned. If big prints have to be toned, it is inadvisable to place more than a couple in the dish at the same time, since there is a certain awkwardness in judging of the amount of tone given to a print which is (say) between two or three. The prints should be placed face up in the solution, and great care should be taken that liquid separates each print from the next one to it, otherwise there will be patches of unequal toning. The dish containing the prints in the solution should be gently rocked to secure a proper mixture of the solution which may have been robbed of its gold in those strata next surface of the prints. The rocking is also advisable to cause any adhesion between two deep-toning prints impossible. If the prints be of small size, a dozen or more may be toned at one operation. Each print should be frequently brought to the surface of the liquid, and examined in order to see how the toning action is progressing. When one print is judged sufficiently toned, it is removed to a dish containing pure water, and another untoned print placed in the dish in its stead. This operation is continued till all the prints are toned. We have heard that it has been suggested to place the prints in water containing alittleacetic acid or common salt, in order to stop the toning action continuing from the solution which may be held in the paper. The former is most undesirable, acetic acid, as we shall see presently, decomposing the fixing bath.
As to the addition of common salt, we can scarcely give a favourable opinion regarding it. The addition of a chloride does, in truth, alter the colour of the deposited gold (seeante), and it may be this that gives rise to the opinion that it corrects toning action. Of one thing we have little doubt, however, and that is, that the addition of any large amount of common salt will tend to turn the albumenate of silver into chloride, which in fixing will materially weaken the print. When giving the formula of the toning baths, we have indicated the depth to which toning should take place. One great point to attend to is, that a printshould not be a slatey colour when fixed, and that can only be avoided by stopping the toning action when the print arrives at a blue-purple stage.
The toning bath, when used, should be replaced in the bottle, and we recommend that it be kept in a dark place, otherwise any chloride of silver which finds its way into the solution will darken and be a nucleus for the precipitation of gold from the solution. The energy of the toning bath would, in consequence, be wholly gone. It will be found that in very cold solutions formed in winter the toning action is much slower than in summer, and we need scarcely point out that this due to the fact that cold invariably retards chemical action. This retardation is not advantageous, and it will be found positively hurtful as to the colour of the precipitated gold. We therefore recommend that the toning solution and the dish in which it is to be poured should be warmed before the fire, the former to a temperature of about 70°F., and the latter a little higher. By this means the toning action will take place as rapidly as in warm weather, and the same tones be produced. It must berememberedwe are writing for all; not for those alone who have an elaborate arrangement for keeping their operating rooms at a good temperature in all weathers, but also for those who cannot afford the luxury. It is for this reason that we have given the above directions.
Sir J. Herschelwas the first to point out that hyposulphite of soda would dissolve chloride of silver, and subsequently it has been found that it dissolves almost every organic salt of silver. In our early chapters we gave some examples of this. When we add hyposulphite to a salt of silver, such as the chloride, we get one of two reactions, the formation of a nearly insoluble double hyposulphite of soda and silver, or a readily soluble one.
The first insoluble double hyposulphite is formed when there is only a small quantity of sodium hyposulphite present; the soluble kind when the sodiumhyposulphiteis in excess. Since it is the soluble kind which we wish to form, it is manifest that the presence of a sufficiency of hyposulphite in the fixing bath is necessary. If not, we have left the insoluble form on the paper. If either of these two kinds of hyposulphite be madein a test-tube, we can readily simulate the effect of atmospheric exposure. If slightly acid water be added to the hyposulphite, it will be seen, when chloride of silver has been dissolved by the hyposulphite, that the precipitate or solution commences to blacken, sulphide of silver being formed. On the other hand, if we take albumenate of silver, and dissolve it in hyposulphite of soda, we shall find that the addition of acid gradually causes a yellow-looking compound to separate out, and it is probably this body formed in the paper which causes the gradual yellowing of the whites of silver prints.
What is taught us, then, by this observation is, that by thorough washing we must try and eliminate all traces of hyposulphite of silver, and, indeed, of the hyposulphite of soda, since the latter decomposes as rapidly in the presence of acid as does the silver compound.
The formula for the fixing bath which we recommend is:—
The addition of the ammonia prevents any possibility of an acid reaction arising, and otherwise softens the film of albumen and the size of the paper, causing more rapid fixation and more thorough washing. Another thing the ammonia does is, that it prevents, in a great measure, blistering of the film of albumen, which is common in some highly-albumenized paper.
Experience has shown that one ounce of solid hyposulphite will fix with safety three sheets of paper, so that an idea can be formed of how much must be used for a day's printing. The hyposulphite bath which has been used one day should never be used the next, since it invariably contains the germs of decomposition in it from some cause or another. Indeed, the appearance of the solution indicates this is so, since it is usually of a yellow or brownish appearance.
The time required for fixing a print varies with the thickness of the paper used. As a rule, prints on the medium-sized paper require ten minutes' soaking in the bath, whilst thick-size requires fifteen minutes. Whilst toning, the dish containing the hyposulphite should be kept in a gentle rocking motion, as in toning, and for the same reasons. Prints may be examined from time to time, to see how the fixing progresses. When a print is not quite fixed, small spots of dark appearance will be seen when it is examined by transmitted light. The operation of fixing should be continued after these disappear for at least three or four minutes, in order that the hyposulphite of soda in the dish may get impregnated with the double silver and sodium salt which is in the print, and thus render washing more effectual. It should be noted that the dish for fixing should be at least as long and wide as the dish used for toning; that it should be deeper when, as a rule, all the prints are fixed at one time. Care should be taken that dishes which are used for sensitizing, toning, or fixing,should not be used for anything else. The glaze of porcelain dishes is often soft, and frequently absorbs a certain amount of the solutions used. Thus, if a porcelain dish be used for a solution of any aniline dye, it will often be found that it is permanently stained. Colour in this last is merely indication of what happens with any other solution. It will thus be seen that it is a mistake to use a dish for fixing when the glaze is cracked, since old hyposulphite must find its way into the body of the fresh solution that may be used, and thus institute a spontaneous decomposition, and a consequent want of permanence in the print. For our own part, we believe that a gutta-percha dish is a safer dish to use than any other, since it is impervious to any solution, and can be well scoured after fixing, and before being again brought into use. We believe that much of the fading of prints may be traced to the use of unsuitable dishes for fixing.
Thereare very many apparatus designed for washing prints; but we believe that, where few prints have to be treated, careful hand-washing is as superior to machine-washing, as hand-made paper is to machine-made. In our own practice we take the prints from the fixing-dish, and immerse them in a large puncheon of water, and allow them to soak for five minutes, after which we carefully pour off all the water, and replenish with fresh, in which we leave them for a quarter-of-an-hour. After that we take the prints and place them on a glass slab, and, with asqueegee, squeeze as much water as possible out of each separately; this we repeat twice. After two more washings of a quarter-of-an-hour, we then wash for half-an-hour, and, with a sponge, dab them as dry as possible, and again immerse for half-an-hour. After repeating this operation twice, we allow a stream of running water to pour into the puncheon for a couple of hours, carrying the stream through an india-rubber pipe, at the end of which is a glass tube, to the bottom of the puncheon, and so that the pour of water goes against the side. By this means there is a constant stir in the water, and the water flows over the edge of the puncheon. It is convenient to cut a notch in the top rim of the puncheon, so that the water may find an exit before reaching thelevel of the rim. The prints are then taken out, sponged once more, and dried. By this arrangement we have got prints which are perfectly unfaded, though they have been in existence eighteen years, and have been to the tropics, and in the dampest climates. This method of washing, though tedious, should be applied to all prints; but, in the present day, it can hardly be hoped that it can be immediately adopted, on account of the attention it requires; we therefore describe an apparatus which can be used. It was designed by Mr. England, and consists of a working trough, as shown in the figure, which is automatically worked by an overshot wheel. We need not enter into the details of the invention, as they are self-evident.
Fig.28.
Fig.28.
This washing arrangement causes the prints to be alternately soaking in water, and draining. Whilst in the water they are perpetually being shaken apart by the movement of the tray, and thus every part of the print gets washed, and it is almost impossible for two prints to stick together. In all washing apparatus there is a danger of air-bells forming on the surface of the prints while in the water, but in this form there is the advantagethat whilst draining the air-bells must break, and so water on rising to the level of the prints can obliterate any of the evil effects which would be caused by their being perpetually remaining on one spot. It is useless to attempt to describe other forms of the apparatus, since there are so many; we have chosen one which appears to us to be a satisfactory form.
The following tests for the elimination of hyposulphite are taken from another work of this series.[26]
"The following is a most delicate test.
"Make the following test solution:—
"The addition of a few drops of this rose-coloured solution to a pint of water will yield a slightly pink tinge. If there be any trace of sodium hyposulphite present, this colour will give place to one of a greenish hue.
"If the permanganate be not at hand, the following well-known starch iodide test may be adopted:—
"Take about two drachms of water and a small piece of starch about the size of a small pea; powder and boil the starch in the water till the solution is quite clear; add one drop of a saturated solution of iodine in alcohol to this clear liquid. It will now become dark blue. Of this solution drop two drops into two clean test tubes, and fill up one with distilled water and the other with the water to be tested; a faint blue colour should be perceptible in the first test tube. In the second test tube, should hyposulphite be present, this blue colour will have disappeared, the iodide of starch becoming colourless in its presence. The best mode of comparing the two waters is by placing a piece of white paper behind the test tubes.
"It frequently occurs that though sodium hyposulphite cannot be detected in the washing water, it may be present in the paper itself. The paper on which most prints are taken being sized with starch, if averyweak solution of iodine be applied with a brush across thebackof a print, a blue mark will indicate theabsenceof the hyposulphite. Care must be taken that the iodine solution isveryweak, otherwise a part of the iodine will first destroy the trace of the salt, and then the remainder will bring out the blue re-action."
We finish this chapter by quoting our maxims to be observed in printing.
"Maxims for Printing.
"1. The prints should have the highest lightsnearlywhite, and the shadows verging on a bronzed colour before toning.
"2. Place the prints, before toning, in the water, face downwards, and do not wash away too much of the free nitrate of silver.
"3. The toning solution must be neutral or slightly alkaline, and not colder than 60°.
"4. Tone the prints to purple or sepia, according as warm or brown prints are required.
"5. Move the prints, in both the toning and fixing solutions, repeatedly, taking care that no air-bubbles form on the surface.
"6. Take care that the fixing bath is not acid.
"7. Use fresh sodium hyposulphite solution for each batch of prints to be fixed.
"8. Wash thoroughly after and before fixing.
"9. Make a sensitizing bath of a strength likely to give the best results with the negatives to be printed.
"10. Print in the shade, or direct sunshine, according to the density of the negative."
Printson plain paper are sometimes of use; for instance, they form an excellent basis on which to colour. They are of course duller than an albumenized print, since the image is formed more in the body of the paper than on the surface. The following formula may be used:—
The gelatine is first swelled in cold water, and then dissolved in hot water, and the remaining components of the formulæ are added. It is then filtered, and the paper is floated for three minutes, following the directions given onpage 10. If it be required to obtain a print on plain paper in a hurry, a wash of citric acid and water (one grain to the ounce) may be brushed over the back of ordinary albumenized paper, and, when dried, that side of the paper may be sensitized and printed in the ordinary manner. For cold tones the wash of the citric acid may be omitted.
The toning and fixing are the same as described inChapters XII.andXIII.
Thefollowing is taken from another volume of this series.[27]
To Mr. Henry Cooper we are indebted for a valuable printing process, founded on substituting resins for albumen or other sizing matter. The prints obtained by this process are very beautiful, and lack that gloss of albumen which is often called vulgar and inartistic.
The following are the two formulæ which Mr. Cooper has communicated to the writer:—
When the resins are dissolved in the alcohol, the paper is immersed in the solution, then dried and rolled. The sensitizing bath recommended is as follows (though the strong bath given atpage 126will answer):—
To the water is added as much gelatine as it will bear without gelatinizing at 60° Fah.
The second formula gives very beautiful prints, soft and delicate in gradation.
The paper is first coated with an emulsion of white lac in gelatine, which is prepared as follows:—
3 ounces offreshwhite lac are dissolved in 1 pint of strong alcohol, and after filtering or decanting, as much water is added as it will bear without precipitating the lac; 1 ounce of good gelatine is soaked and dissolved in the pint of boiling water, and the lac solution is added with frequent stirring. If, at any stage of this operation, the gelatine is precipitated, a little more hot water must be added. The pint of lac solution ought, however, to be emulsified in the gelatine solution.
To use the emulsion, it is warmed, and the paper immersed in or floated on it for three minutes. When dry, the coated surface is floated in the following for a couple of minutes:—
When dry, it is sensitized on a moderately strong bath (that given on the last page will answer).
If more vigour in the resulting prints be required, it is floatedon:—
This last bath improves by use, probably by the accumulation of silver nitrate from the sensitized paper.
Any of the toning baths given inChapter XII.will answer, though Mr. Cooper recommends:—
2 dr. of sodium acetate are to be placed in the stock-bottle, and the above solution filtered on to it. This is made up to 20 ounces, and is fit for use in a few hours; but it improves by keeping.
In commencing to tone, place a few ounces of water in the dish, and add an equal quantity of the stock solution, and if the toning begins to flag a little, add more of it from time to time.
With the resin processes over-toning is to be carefully avoided.
Resinized paper may be obtained from most photographic dealers, we believe, and for some purposes is an admirable substitute for albumenized paper.
Mr. W. T. Wilkinsonhas recently brought forward the notion of using gelatine instead of albumen as a medium for holding the silver chloride in printing. He uses the following formula:—
The gelatine is allowed to swell in the water, and, by the aid of heat, is dissolved; the barium chloride is then added. Next he prepares—
and adds this to the former, little by little, in a large bottle with much shaking, or pours it slowly into the former in a large jar, stirring briskly the whole time. This makes an emulsion of silver chloride, and is used without washing. When required for use, the gelatine, which will have set when cold, is swelled by placing the jar containing it in hot water, and is then transferred to a dish. The dish should be kept warm by being placed, supported on small blocks, in a tin tray (about two inches larger in dimensions every way than the dish) filled with hot water, thetemperature of which should be about 150° F. to commence with. Saxe or Rive paper may be coated by rolling the sheet face outwards, and placing the edge of the roll upon the gelatine. The two corners of the paper in contact with the solution are then taken hold of by the fingers, and raised. The paper will unroll of itself, and take up a thin layer of the gelatine emulsion. The sheet of paper is then suspended to dry. All these operations are, of course, conducted in the dark room. The behaviour of the paper in the printing-frame is precisely the same as albumenized paper, and the washing and toning are conducted in the same way. For a fixing bath is used—
The washing after fixing is more rapid than with albumenized paper. It is washed in ten or twelve changes of water for ten minutes, and then placed for five minutes in an alum bath made as follows:—
The print is washed in a few changes of water, and the prints are ready for drying and mounting. The advantage of the alum bath is that the hyposulphite is destroyed into harmless products, and the gelatine is rendered insoluble by it. In the formula given there is large excess of chloride, and we recommend that instead of using 2,440 grains of barium chloride, 2,050 grains be used. (Mr. Wilkinson has used that amount of the barium salt that would be required exactly to convert 1,700 grains of silver nitrate into silver chloride, if the formula for barium chloride were BaCl3instead of BaCl2.) It will be seen that whichever formula is used, there is no silver left to combine with the gelatine, and hence the image will be entirely formed by metallic silver, and not an organic salt of silver.
Inmany establishments the prints are taken direct from the washing water, and hung up by American clips, and thus allowed to dry. When this is done, the prints curl up as the water leaves the paper, and they become somewhat unmanageable. If prints have to be dried at all before mounting—and they must, unless they are trimmed before toning—a better plan is to make a neat heap of some fifty or sixty of the same size (say cartes), place them on blotting-paper, and drain for a time, and then in a screw-press (such as is used to press table-cloths, for instance) to squeeze out all superfluous water. After a good hard squeeze the prints should be separated, and the plan adopted by Mr. England carried out. He has frames of light laths made, of about 6 feet by 3 feet, and over this frame is stretched ordinary paperhanger's canvas. The prints are laid on this to dry spontaneously, and they cockle up but very little. The frames, being light, are easily handled. After the squeezing is done, supposing the room in which they are placed be not very damp or very cold, the prints will be ready for trimming and mounting in a couple of hours. To our minds there is nothing superior to this mode of drying, since the squeezing in the press tends to eliminate every slight trace of hyposulphite which might be left in them.
Trimming the Prints.—Perhaps more prints are ruined in trimming than in any other way, when the operator is inexperienced, since it requires judgment to know which part of the print to trim off, so that a right balance shall be kept. In trimming landscape prints, it is impossible to give any set rules; the judgment as to what is artistic must be the guide. Of one thing we may be certain, that, unless the operator who took the original negative knows exactly how to balance his picture on the focussing-screen, the print will always bear cutting down in one direction or the other. Such a clipping, of course, alters the size of the print, which, if it be one of a series, will be a misfortune; but, on the other hand, the artistic value of the individual print will be increased.
For portraits there are some few rules which should be followed in trimming. Always allow the centre of the face to be a little "out" from the central line of the print, making more space on the side towards which the sitter is looking. Allow a carte or cabinet to be cut in such a way that, if the sitter has been leaning on something, it does not seem as if he had been leaning on nothing. Should there be an unintentional lean on the part of the sitter, trim the print so that he appears in an upright position.
To trim the print, there should be the various sized shapes in glass used. Thus there should be glasses with bevelled edges for the carte, the cabinet, and other sizes, which can be laid on the print as a guide to the trimming. The absolute trimming may be done either by shears or by a knife, a leather cutters' knife being excellent, since it is rounded, and can be brought to a keen edge very readily. When the knife is used, the print is placed on a large glass sheet of good thickness, the pattern placed over it, and, whilst this is held down by the left hand, the knife is used by the right, keeping it close to the edge of the pattern glass. When shears are used, the print is held against the pattern glass by the left hand, and each side trimmed by one clip, taking care to make the cut parallel to theedges of the pattern glass. It requires a little practice to prevent clipping the glass as well as the paper, but for small sized prints, such as the carte, the shears have a decided advantage over the knife.
For cutting out ovals, Robinson's trimmer is an excellent adjunct to the mounting-room, and in this case ovals stamped out of sheet brass are used as guides.
Fig.29.
Fig.29.
The figure will show the action of the trimmer. The small wheel is the cutter, and, being pivotted, it follows the curve against which it is held. It is better to cut out prints with this trimmer on sheet zinc in preference to glass, the edge of the wheel being kept sharp for a longer time than where the harder glass is used. To use the trimmer, the print is placed on the sheet of zinc, the oval mask (or square mask, with slightly rounded corners) is placed in position on it. The wheel of the trimmer is brought parallel to, and against, the edge of the mask, the handle being grasped by the right hand, the thumb to the left, and the fingers on the right. A fairly heavy downward pressure is brought to bear on the trimmer, and at the same time the wheel is caused to run along the edge of the mask. The cut should be clean, and the join perfect, if proper care be taken. It is desirable to practise on ordinary writing paper before it is taken into use for prints. Square masks with very slightly rounded corners can be used; the smaller the wheel, the less curved the corners need be. It will be seen that there is a limit to smallness of the wheel used, since, if too small, the stirrup on which it is pivoted would rest upon the mask. The larger the wheel the easier is the cutting.
With larger sizes than the carte or the cabinet, mounting mayoften have to be delayed, since it is easier to keep a stock of unmounted prints (say landscapes) unmounted than it is when they are mounted. In this case the prints should be put away as flat as possible. The plan of drying we have indicated takes out the "curl," but even then they will not be flat enough to be handily put away. We therefore recommend the practice of stroking the prints. A flat piece of hard wood, about 1 foot long and 11/2inch broad, and the thickness of a marquoise scale, has its edges carefully rounded off. The print is seized by one corner in one hand and unrolled; the face of the print is brought in contact with a piece of plate glass. The "stroker," held by the other hand, is brought with its rounded edge on to the back of the print near the corner held by the first hand. Considerable pressure is brought upon the stroker, and the print is drawn through between it and the plate. The print is then seized by another corner and similarly treated. By this means a gloss is put upon the print, and the creases and cockles are obliterated. The print is now ready for trimming.
It is well to have a square of glass with true edges cut to the size of the pictures. The prints should be trimmed upon a sheet of plate glass, a sharp penknife being used to cut them. A rough test for ascertaining if the opposite sides are equal is to bring them together, and see if both corners coincide.
It may sometimes be found useful to cut out a print into an oval. The following method for tracing any ellipse may be employed:—On a thickish piece of clean paper draw a line A B, making it theextremewidth of the oval required. Bisect it at O, and draw D O C at right angles to A B. Make O C equal tohalfthe smallest diameter of the ellipse. With the centre C and the distance O B, draw an arc of a circle, cutting A B in E and F. Place the paper on a flat board, and at E and F fix two drawing-pins. Take a piece of thread and knot it together in such a manner that half its length is equal to A F. Place the thread round the two pins at E and F, and stretch it out totightness by the point of a lead pencil. Move the pencil guided by the cotton, taking care to keep it upright. The resulting figure will be an ellipse. Modifications of this figure may be made by making a second knot beyond the first knot, and placing the point of the pencil in the loop formed. When the figure has been traced in pencil on paper, it should be carefully cut out with a sharp penknife, and placed on the print which is to be trimmed into an oval. When so placed, a faint pencil line is run round on the print, and the cutting out proceeds either by scissors or penknife.
Fig.30.
Fig.30.
Thereare many photographers who, unfortunately, are quite indifferent as to the medium they use in mounting the trimmed photographs. So long as the medium will cause the adherence of the back of the print to the cardboard employed, they are perfectly satisfied, whether it be paste fresh or sour, or starch or gelatine in a similar condition. If any of our readers have had the misfortune to have their rooms papered with rancid paste, they will have noticed that the unpleasant smell attending it has not been removed from the room for weeks, and that there is a liability of the return of the disgusting odour when the air is at all damp. In this case the fact that decomposition is going on is detected by the olfactory nerves, because the quantity is considerable. It is none the less true, however, that every square inch of the surface of the wall paper is undergoing the same ordeal, and that if it contains any colour, &c., which would be affected by decomposing organic matter, there would be but small chance of the paper retaining its fresh appearance. Were a silver print mounted with the same paste, we need scarcely point out that danger to its permanency is to be apprehended. Paste, we know, is as a rule tabooed, but there is no occasion for it to be so if care be taken that it is absolutely fresh when employed in mounting. In looking for a mounting material, we shouldendeavour to find something which does not readily take up moisture. Glue, gelatine, dextrine, and gum are all inadmissible on this account; on the other hand, starch, arrowroot, cornflour, and gum tragacanth, when once dry, do not seem to attract moisture.
Referring to glue, Mr. W. Brooks says[29]that he has recently seen many photographs which have been mounted with that medium, and in some cases, where the glue has been put on too thickly, it swells up into ridges, showing marks of the brush with which it is applied, and each ridge after a time turns brown. The same writer is not wholly in favour of starch, but in our own opinion pure white starch is as good a material as can be met with. To prepare it for use as a mountant, a large teaspoonful of starch is placed in the bottom of a cup, with just sufficient cold water to cover it. This is allowed to remain for a couple of minutes, after which the cup is filled with boiling water, and well stirred; the starch should then be fairly thick, but not so thick as to prevent a brush taking up a proper supply for a good sized print. We will suppose that we are going to mount a day's work of carte-de-visite prints. In a former chapter we have said that it is desirable that the prints should be left damp. If they are dried, they should beslightlymoistened, and placed in a heap one above the other, as by so doing the moisture is confined, and one damping of all the prints is sufficient. In our own practice we have, as is natural, all the prints with the faces downwards. A stiff bristle brush is then dipped into the pot containing the starch, and the starch brushed over the back of the top print. This one is then carefully raised from the print beneath it, and, supposing it to have been properly trimmed, it is laid upon the card, and pressed down by means of a soft cloth, and placed on one side to dry. The next print is then treated in the same manner, and so on. By this plan no starch gets onthe face of the prints, which is a desideratum. With a little practice, just sufficient starch will be brushed on each carte, and no more. Young hands, however, are sometimes apt to give more than a fair share to them; in this case, after pressing the print down with the soft cloth, it may be useful to place on the print a piece of writing paper, and press all superfluous starch out by a rounded straight-edge, or an ivory or wooden paper knife. The card in this case should be placed on a slab of thick glass, so as give an even pressure. The starch, which will exude beyond the edges of the card, should be carefully wiped off with acleancloth.
This is of course a method to be adopted only in the case of bungling mounting, but it is useful then, and may save a carte. It should be remembered that the less mounting medium used, the greater is the chance of a silver print not fading.
To mount larger prints, the back should be slightly damped, and the brush with the starch applied with cross strokes, so that every part is covered. Particular care should be taken that the corners and edges are not missed, since it often necessitates re-mounting the print, which is to be avoided as far as possible, since it is a troublesome matter. The rounded-edged ruler, and the sheet of white paper, is also useful here, since over a large surface there is more difficulty in getting even layers of starch, than over smaller ones. When a print has to be mounted with a margin, the places where the top corners have to come should be marked with a fine pencil point. By a little dexterity, the top edge of the print, the back of which has been covered with starch in the manner described, can be brought into the position indicated by these dots, and be then lowered without puckers or folds. It should be remembered that the print should just cover the pencil marks, since it is almost impossible to erase blacklead with india-rubber, if any starch should by accident get on it.
It is well to dry these prints under pressure, since the cardboardis apt to cockle. A couple of boards rather longer than the prints suffice for the purpose. The mounted prints are laid between them, a sheet of clean blotting-paper separating each, and a few weights placed on the top board. For prints of moderate size, a table-cloth press is an excellent substitute.
As to the kind of mounts to be used, opinions vary. To our mind, the simpler they are, the better they look. It is not rare to find a regular advertisement of the photographic establishment below a carte or cabinet print. To say the least of it, this is bad taste, and we are sure it is bad art. If the work be good, it needs no recommendation; and if it be bad, the less of an advertisement that appears, the better it is for the photographer. At the back of a carte or cabinet is the place where any advertisement should appear; but even here it may be overdone. When we find the back of the carte got up with any amount of gold-lettering flourishes, and no blank space on which the eye can rest without encountering some one especial merit of the artist, we may expect to find on the front of the card the same kind of tawdry work. It is seldom advisable to have the mount of a white colour, though for cartes or cabinets, in which the margin will be hidden in the album, this is not of much consequence; but for prints in which the margin shows, it is generally advisable to have some slight tint visible, preferably of a cream or buff colour. There are some classes of work which will, however, bear a white margin, but it is rarely the case; and we advise, as a general rule, that there should be some tone on it, to prevent its attracting the eye away from the picture by its whiteness. Black mounts are much in vogue at the present time, and they are effective and artistic; but chemical analysis has shown them not to be safe, since they are enamelled with substances which are apt to induce fading. A good and stable black mount is a desideratum, which it is to be hoped will be found before long.
Notwithstanding our preference for starch as a mountant, wegive a method of preparing glue for the same purpose. The glue used should be light, and as clean as possible. It should be shredded and soaked in sufficient clean water to cover it for five or six hours; any dust which may have adhered to it will find its way into the water. The water should be poured off and replaced by an equal quantity of fresh. The vessel containing it is heated over a small gas jet or spirit lamp until solution takes place. The liquid is then thinned down with warm water till it is of proper consistency, a point which is soon learned by a little practice. An ordinary small glue pot will be found convenient.
It is sometimes useful to have at hand a mounting solution which will not cockle the mount, and the late Mr. G. Wharton Simpson gave a formula which is very good in this respect. Fine cut gelatine or shredded glue is swollen in the least possible quantity of water, and this is boiled with alcohol, with much stirring. If 80 grains of Nelson's No. 1 fine cut gelatine are taken, 3 dr. of water should be used for making it, and to it 2 oz. of alcohol be added. When cool this sets into a jelly, and can be used by letting the bottle into which it has been transferred stand in hot water. Prints can be mounted on foolscap paper with this medium without any serious cockling being apparent.
It should be recollected that no two batches of paper will mount exactly alike, some expanding more than others. It is well to mount a trial print before doing many, to see exactly how the paper under manipulation behaves.
Rolling the Prints.—After the prints have been under the hands of the retoucher, they should be rolled in a rolling-press in order to give a brightness to the printed image. It would be invidious to point out any particular press that should be used. Suffice it to say, there are many excellent ones in the market. The directions for cleaning and using the press are supplied with each machine; we therefore refrain from saying anything about them.
Thebath solution is sometimes repelled by the paper, and this is found chiefly in highly albumenized paper, and is generally caused by the paper being too dry. Passing the sheet of paper over the steam from a saucepan will generally effect a cure.
Small white spots, with a black central pin-point, are often met with in prints. Dust on the paper during sensitizing will cause them, the grit forming a nucleus for a minute bubble. All paper should be thoroughly dusted before being floated on the sensitizing bath.
Grey, star-like spots arise from small particles of inorganic matter, such as ferric oxide, lime, &c., which are present in the paper. They become more apparent by decomposition during the printing operations. They may generally be discernible by examining the paper by transmitted light.
Bronze lines (straight) occur through a stoppage during floating the paper in the sensitizing solution. Should the lines be irregular, forming angles and curves, it is probable that a scum of silver oxide, &c., may be detected on the surface of the sensitizing solution. A strip of blotting-paper drawn across the bath will remove the cause of the defect.
Should the print appear marbled, it may be surmised that the sensitizing solution is weak, or that the paper has not been floated sufficiently. In some cases it may arise from imperfectalbumenizing; but in ordinary commercial samples the cause can be easily traced.
Red marks on the shadows may appear during toning, and are very conspicuous after fixing. They generally arise from handling the paper with hot, moist fingers after sensitizing; greasy matter being deposited on the surface, prevents the toning bath acting properly on such parts.
Weak prints are generally caused by weak negatives. Such can be partially remedied by paying attention to the strength of the sensitizing bath (seeAppendix), and by using washed paper.
Harsh prints are due to harsh negatives. They can generally be remedied by paying attention to the mode of printing, as given inChapter IX.If the negative be under-exposed and wanting in detail, there is, however, no cure for this defect.
A red tone is due to insufficient toning; whilst a poor and blue tone is due to an excess of toning.
The whites may appear yellow from imperfect washing, imperfect toning, imperfect fixing, or from the use of old sensitized paper.
Should prints refuse to tone, either the gold has been exhausted, or else a trace of sodium hyposulphite has been carried into the toning bath by the fingers or other means. A trace of hyposulphite is much more injurious to the print than a fair quantity of it. Should the toning bath refuse to tone after the addition of gold, it may be presumed that it is contaminated by a trace of sodium hyposulphite.
A dark mottled appearance in the body of the paper indicates imperfect fixing, combined with the action of light on the unaltered chloride during fixing. If the fixing bath be acid, the excess of acid combines with the sulphur, and forms hydrosulphuric acid, which will also cause the defect.
The cause of mealiness or "measles" in the print has been explained inpage 32.
Thevalue of an encaustic paste in improving the effect of photographic prints has become very generally recognised amongst photographers. A good encaustic confers three special benefits on the print: it gives depth, richness, and transparency to the shadows; it renders apparent delicate detail in the lights which would otherwise remain imperceptible; and it aids in protecting the surface, and so tends to permanency. One of the writers has in his possession prints that were treated with an encaustic paste thirteen years ago, which retain all their original freshness and purity, while prints done at the same time from the same negatives have gone, to say the least of it, "off colour."
Various formulæ for the preparation of encaustic pastes have been published, and many of them very excellent. The qualities required are, easiness of application, and the capacity of giving richness and depth without too much gloss, and of yielding a hard, firm, permanent surface. For a proper combination of all these qualities, nothing has ever approached the paste of the late Adam-Salomon, of which the following is the formula:—
The wax is cut into shreds, and melted in a capsule over a water bath. Placing it in a jar, and the latter in a pan of hot water, will serve. Powder the elemi, and dissolve it in the solvent, using gentle heat. Some samples of elemi are soft and tough, and will not admit of powdering, in which case it may be roughly divided into small portions, and placed in a bottle with the solvents. Strain through muslin, and add the clear solution to the melted wax, and stir well. It is then poured into a wide-mouthed bottle, and allowed to cool.
The encaustic paste is put on the prints in patches, and then rubbed with a light, quick motion, with a piece of flannel, until a firm, fine surface is obtained.
We give another simple formula which is efficient, though we ourselves prefer the above.
and thinned down, if necessary, till it has the consistency of "cold cream."
Yet another is—
Thereare several modes of enamelling prints, but there is none better than that described by Mr. W. England, which we quote in his words. "I have a glass having a good polished surface (patent plate is not necessary), and rub over it some powdered French chalk tied up in a muslin bag. Dust off the superfluous chalk with a camel's hair brush, and coat with enamel collodion. I find it an improvement to add to the collodion usually sold for the purpose 2 dr. of castor oil to the pint. When the collodion is well set, immerse the plate in a dish of water. When several prints are required to be enamelled, a sufficient number of plates may be prepared and put in dishes; this will save time. Now take the first plate, and well wash under a tap till all greasiness has disappeared; place it on a levelling stand, and pour on as much water as the plate will hold. Then lay the print on the top, squeeze out all the water, and place the plate and print between several thicknesses of blotting-paper to remove all superfluous moisture. The plate, with the print in contact, should now be placed in a warm room to dry spontaneously, when the print will come easily from the glass. Care should be taken not to attempt to remove the print till quite dry.If the pictures required to be enamelled have been dried, it will be necessary to rub over them some ox-gall with a plug of soft rag; otherwise the water will run in globules on the surface, and make blisters when laid on the collodion.
"I may mention that prints done in this way lose their very glossy surface on being mounted, but retain their brilliancy, which I think is an improvement, as I dislike the polished surface usually given to the print when gelatine is employed."
Atone time there was a rage amongst photographers to produce cameos, and, for this purpose, a special piece of apparatus was required to produce the embossing. The figure will explain it.