US76660A - Isaac rehn- - Google Patents

Description

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Letters PatentNo.-76,660, dated Apr-2'1 14, 1668.

.IJIODE 0F PRINTING PHOTOGRAPHIG PIUTUBES.

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TO ALL WHOM IT MAY (.lOIIQERIT-:- ho 7mm" a To it known that I, IsAAcREHrgof the'city and county .of Philadelphia, and State of Pennsylvania, have invented a new and improved Mode of Preparing a Sensitive Surface for Photographic Printing on Non Absorbent as well as Absorbent Materials, and I do hereby declare thefollowing to bee full and exact description of the same. p p

The object of my invention is to enable any one to so prepare the surface of painted canvas, boards, iron plates, or other material, that photographic printing ou'the same may be easily andsuccessfullyaccomplished, and especiallyenlargements, by the solar camera fovcoloringin oil or other colors, or to be preserved plain.

The mode usually employed for enlargements'is that of making the print upon paper, and pasting the same upon canvas, preparatory to coloring, although attempts, with partial success, have been made to print such enlargements direct upon canvas, though the methods were such thattheresults were very unsatisfactory, as well as also to injure the canvas, by acting upon the painted ground. By the method'I employ, and am about to describe, the resulting picture is clear and strong,- easily and surely made, while the canvas'is in nowise injured.

Iprocecd as follows: Take, of pure zinc-white, one ounce; albumen of fresh eggs, one and a half ounce; salt, v

or' chloride of ammonium, twenty grains; solution. of ammonio-nitrate of silver, four (4) drachms, containing thirty grains of nitratc of silver to each drachm. Dissolve the salt in the albumen; then grind fine, Oil-Ia ainter's slab, the zinc-white in a portion of the albumen; then add the remainder, and mix it uniformly; place the-pigment mixture in a Wcdgewood mortar, and proceed to the dark room; then add the silver/solutiomwhich will immediately coagulate the albumen 5 1 take the pestle, and tritnr atc the coagulum until it becomcs 'smooth.

and pulpy. It is then ready for use. Now, take a fiat camels hair brush about two inches wide, and 'paint evenly over the canvas, or other material, with this combination, and it is ready for use when dry, or, if it is desired to print with the solar camera, it is quite as good vret. If a very intense print is required, the coating may, when dry, be subjected to the vapor of ammonia, which will still add to the sensitivenessof the coating.

. This combination is very sensitive to light, and hence due caution must be observed in regard to'it, seas not to injure the whites of the picture? It has also the quality of taking very kindly to all kind of surfaces, oily or not, and may be, therefore, very easily laid quite free from bubbles or other defects. I have had quite as good results by first applying the non-coagulated coating, allowing it to dry,then flowing the silver solution over the coating; but this method is not so economical orconvenient as the process first described.

The method of preparing the ammonio nitrate of silver solution is as follows;

Take, of nitratcnt' silver, one ounce. I

Water, one ounce,

Ammonia, quantity sullicient.

Pure nitric held, two draehms. I r

Dissolve the silver in the watcr;-'remove a small portion, say, one drachm. To the larger portion add carefully sufiicient' ammonia to precipitate the silver, and re-dissolve the precipitate, guarding against any excess of ammonia. Thenladd the remainingdrachm of the silver solution,ito insure aidccirlcd excess of silver. Lastly, add-the two drnchins of nitric acid, and the solution is ready for use at any time. I l '7 4 "After the printing process has been carried as far as: may be desired, it remains only to it the impression, which maybe dono in the-.nsual way, namely, the rinsing away ofthc free nitrate of silver, and then pouring over the picturea solution of'hyposulphite of soda for a few minutes, afterwards removing nit hyposulphitcof soda by washing the print under a gentle stream. 1 r I T-headvantages of my process arothosc'of facility and certainty in' the production of good results, the applicability of the process to every kind of substauceon which it may be desired to print, and the greater degreeof sensitivcncss of thc'printing-surface over that now employed, which 'scnsitivencss in solar-camera printing is a matter of much importance.

Having described my invention, what I claim, and desire to secure by Letters Patent,- is.- The combination of the pigment, with the salted albumen and silver solution, for the purposes set forth in the above specifications. v

' .I S AAC BEHN.

Witnesses Jenn DAINTY, WILLIAM Runs.