The schedule referred to in the Letters Patent, and making part of the same.
To whom it may concern:
Be it known, that I, James A. Cutting, of the City of Boston, County of Suffolk, and State of Massachusetts, have invented a new and useful improvement in positive photographic pictures on glass, and I do hereby declare the following to be an exact description thereof:
The nature of my invention consists in the use of gum camphor, in addition to the existing materials in the preparation of collodion for positive photographic pictures on glass.
To enable others skilled in the art to make and use my invention, I will proceed to describe the process as follows:
Having prepared the collodion in the usual manner, I take a pint bottle, in which I introduce twelve ounces of collodion, to which I add one drachm of iodide of potassium, dissolved in alcohol. I then shake the mixture thoroughly, and add thereto eighteen grains of refined gum camphor, shaking the mixture again, until the whole is combined, then allow it to settle, when it is lit for use.
The advantages of my improvement consist in the increased vigor of the delineations of the half-tones of positive pictures on glass, giving greater depth and rotundity thereto, which render this combination exceedingly useful for microscopic pictures, as well as the ordinary purposes of portraiture.
T would have it understood that the combination of camphor with iodide of potassium and collodion, as above specified, is adapted solely to the production of positive pictures on glass and not to the production of negative pictures on glass, from which positive pictures on paper may be printed, as a sufficient degree of opacity is not thus afforded for that purpose.
What I claim as my invention, and desire to secure by Letters Patent, is the use of camphor, in combination with iodized collodion, as set forth in the specification.
James A. Cutting.