From Photographisches Archiv.

IT cannot be denied that albumenised paper has contributed largely to the present perfection of photography. Formerly it ways rejected by portraitists because it was asserted that the great brilliancy gave an inartistic effect to the picture. Now, on the contrary, it is rare to see such a thing as a photograph on plain paper. The delicacy, vigour, and brilliancy of the image is wonderfully heightened by albumen, and the negative does not require excessive intensifying in order to yield good proofs, provided only that it is evenly developed. Formerly the practical photographer trusted too much to touching up; and many an imperfect negative was allowed to pass muster with the help of good touching, and it was even the practice in many studios to stop out the backgrounds and produce artificial ones. Also, when it was made use of, more or less broad white lines appeared around the figure. With a print on albumenised paper, on the other hand, there are difficulties in the way of touching up. Not only were all the delicate gradations of tone in mixing the colours more difficult to obtain than with ordinary salted paper, but also the dullness of the touched parts disturbed the general effect of the print; and further, there is an obstacle presented by the difficulty of making ordinary colours cling to the albumenised surface.

The colouring of albumen prints has recently made great progress, and there is scarcely anything that causes a more favourable impression than .a delicately-coloured albumen print, with good chiar oscuro. The manner of colouring is kept secret by many photographers; there are, however, some formulae by which a greater or less degree of success may be obtained in touching up and colouring prints on albumenised paper.

One--perhaps least worthy of recommendation-consists in roughening the print with an ink eraser, i.e., a compound of India-rubber and sand, then colouring and coating with a varnish.

It appears to us better first to coat the whole print or merely those portions of it that are to be touched up with any substance that will cause the water-colours to adhere, and also to rub down the colours with some of the same substance. The best known of such adhesive bodies are:--honey, or any solution of syrup, gum arabic and ox gall. Simply damping the print with water, and subsequently wiping it gently off, will facilitate the application of the colours, and if with the colours a small quantity of gum arabic is mixed, no trace of the touching will be visible, provided, of course, that it has been carefully executed and the colours properly mixed. The addition of a little carbonate of soda to the water makes the re-touching still easier, but the alkalinity of the salt affects some colours too much. My own experience goes to show that the simplest method of colouring albumenised prints . is this:--First cover the entire print with fresh ox gall, by means of a small sponge, or broad brush; then pour it in the usual way with water-colours; and, finally, coat it, when perfectly dry, with any good transparent spirit varnish. The latter is indispensable, since without it the colours appear dull.

Our readers have recently been informed of a method of making the albumenised prints transparent with a varnish and colouring on them, with oil colours on the reverse. This method, after a little practice, produces, even without artistic talent, very fine effects, if the colours are chosen with taste, and applied with cleanliness and not too thickly. It is better to frame a print so prepared at once, and on a white ground, since it is difficult to mount them smoothly on cardboard with aqueous adhesive bodies, such as gum, paste, or glue. Possibly a transparent solution of caoutchouc in benzine might be employed; but I have not tried it, and it might perhaps dissolve the oil colours.

Albumenised paper causes the photographer even more trouble in toning than in colouring and re-touching. The worst trouble is mottling; for, if once present in a paper, there is no means of warding it off. The thicker the paper and the more strongly albumenised, so much the more likely is it to make its appearance. A thin paper, evenly and not too strongly albumenised, shows no mottling, and tones much more easily. In the parts, for instance at the edge of the paper, where there is sometimes too little, sometimes too much albumen present, it will be clearly perceptible that in the former case such places tone much quicker, and become blue grey, while the rest of the print is still brown; whereas, in the latter case, they remain much redder, and in spite of prolonged toning appear as red, and oftentimes very large, spots and streaks. It may generally be noticed that at such red places the water, and, consequently also the gold and silver in the respective baths, are repelled, whilst the whole of the remaining surface keeps wet--a circumstance which fully explains the red colour of those places. That which takes place here on a large scale appear to occur with the mottling in small spots, almost regularly spread over the whole picture, and which on that account remain red. Is it possibly a result of the texture of the plain paper that more albumen is collected, in its hollows than on the other parts, and that hence the former remain redder in the toning-baths? Microscopic examination of a similar paper induced Herr Liesegang to form this supposition. Setting out with the opinion that the repulsion of the baths at such places is the original cause, and that the mottling already begins to form in the silver bath, we should endeavour to find a means of overcoming this repulsion, and so to obtain a regular moistening. Perhaps the addition of alcohol to the albumen bath, and a bath of diluted alcohol before toning, would be of use. At any rate, in many instances in which I have worked with paper inclined to mottle, the evil has been remedied thereby.

A good toning paper free from mottling, and yet sufficiently strongly albumenised, its a very valuable acquisition to the photographer; and he should, therefore, not mind paying rather more dearly for it than usual.

If the operator should have the misfortune to be compelled to work with paper addicted to mottling, he may partly remedy the evil by strong silver baths, five minutes' floating, deep printing from vigorous negatives, thorough washing with distilled water, before toning, and slow and not excessive toning in a somewhat diluted gold bath.