Collotype and Photo-lithography

Before commencing any practical work it will, of course, be necessary to procure various utensils and material not usually found in the photographic studio. All these should be...

=An Ingenious Process=, capable of yielding satisfactory results, is one in which a carbon print is transferred to and developed upon the stone direct. Such operation will prese...

A Collotype plate may be readily produced from any negative, but the highest results are naturally only obtained when the negative is prepared with a view to its special use. Fi...

There are several methods of transferring from specially prepared, or even any strong well-sized paper.[O] As the latter may be most convenient, proceed as follows: Write with a...

The well-polished glass plate must be thoroughly cleaned with alcohol and ammonia, and it should be ascertained that the surface is entirely free from scratches. It is then coat...

=Gelatine.=—The basis of the Collotype process is gelatine—the finest purified animal glue—and the important part it plays in the process demands an acquaintance with its proper...

The etching or damping and rolling-up of the Collotype plate presents difficulties which are greater even than those met with in the preparation of the plate. These remarks also...

=Carbon or Pigment Printing.=—In this interesting process finely ground colouring matter is added to the solution of chromated gelatine, and spread upon paper; or the paper may...

=Air bubbles= in the albumen substratum. These must either by filtration or by the aid of a piece of paper be carefully removed from the solution before it is applied to the pla...

=Chromic Acid=, now usually known as chromium-trioxide—CrO_{3}—is found in beautiful red needles, which are slightly deliquescent. According to the present accepted theory, wate...

=Retouching Prints.=—Under the above heading Leon Vidal, in his work “Traité Pratique le Phototypie,” gives the following directions, which I reproduce from the “Photographic Ar...

An unconditionally good negative is required for photo-lithography, and those who have not seen one produced for the purpose by an expert should endeavour as a first step to do...

And one experienced by all photo-mechanical experimentalists, has been that of obtaining =SUITABLE= and =RELIABLE= material and appliances. A prolonged visit to the best known p...

=The Artotype Company=, of New York, which has acquired Obernetter’s process, proceed on somewhat different lines to those laid down in this work, and an abstract of their proce...

In photo-lithographic operations, quite a different set of conditions has to be considered as compared with Collotype. An explanation is, of course, not far to seek, as both the...

August Albert[L] is of opinion that it is by no means a matter of indifference whether bichromate of potassium or bichromate of ammonia is used in the preparation of the Colloty...

A short chapter may be devoted to the various suggested processes for producing Collotype in natural colours, with which are associated the names of Vidal, Albert, and Obernette...

=Half-tone Negatives= must be softer, and possess more half-tone than requisite for silver printing. When examined by transmitted light, they should appear clear in the shadows,...

There remains to be mentioned another variation of the Collotype process known under the above vague title, the distinctive characteristic of which method of preparing the plate...

The observation by Mungo Ponton of the sensitiveness to light of bichromate of potassium in conjunction with organic substances is but little more recent than the discovery of p...

To Professor Husnik (to whom collotypists are greatly indebted for so many unselfish publications), we owe the origination of this interesting method of producing “magic” prints...