Cambridge.
PHOTOGRAPHIC CORRESPONDENCE.
Photographic Slides for the Magic Lantern.—Might not the collodion process be applied very usefully in the preparation of slides for the magic lantern?
Good slides are always expensive, owing, in great measure, to the accuracy required, where every defect will be magnified some hundred times.
I would suggest that a photographic picture should be taken on the glass plate, and then varnished. The painter should then apply his colours to the opposite side of the glass, using the photographic image as his outline. The colours would then be burnt in, and the varnish and collodion film cleared off.
This plan would be especially useful when the photographic picture had been taken by the microscope.
Thos. Scott, B.A.
Brighton.
Albumenized Paper.—If Mr. Hele will follow the directions contained in a paper of mine which you published in Vol. ix., p. 206., for albumenizing paper, I think he will have no reason to complain of waves, or streaks, or blotches, and will be saved the trouble of the damping process which he uses and recommends to others. ("N. & Q.," Vol. ix., p. 254.) I have done a considerable quantity of paper of Canson, both positive and negative, and also of other makers, Whatman, Turner, Sandford, and Nash, and in all I have succeeded perfectly in obtaining an even coating of albumen. I am convinced from my own experience that the cause of waviness, &c., is due to raising the paper from the albumen too slowly. If the paper be snatched hastily from the solution, air bubbles no doubt will be formed; but if the paper be raised with a steady even motion, not too slow, the albumen will flow evenly from the paper, and it will dry with a perfectly even surface.