538. The Paper

The Paper. A fairly good quality of paper should be used for the process - good writing or drawing paper will generally be found suitable, although most any paper may be used. Some papers require to be sized first, for which purpose arrowroot should be used. A peculiar feature about the process is that the paper employed has a considerable influence upon the color of the final print, some papers giving a much warmer color than others with the same developer. The nearer chemically pure, however, the paper, the greater will be the success in securing rich black images. Where the cheaper qualities of paper are used it will be difficult to secure excellent blacks; therefore, it is advisable when using cheaper grades of paper to develop for the warmer colors.

539. Sizing The Paper

Sizing The Paper. As previously stated, it is not necessary to size the paper; but if the best of results are to be secured it will be found advisable to coat the paper with a solution prepared by grinding in a mortar 10 grains of arrowroot in about 1/4 ounce of cold water, and then adding 5 ounces of hot water and bringing to a boil, when the milkiness will disappear.

540. In sizing the paper you can either float it upon the solution, being sure that all air-bells are expelled, or, the sizing may be brushed into the surface of the paper with a camel's-hair brush.

541. Sensitizing The Paper

Sensitizing The Paper. Pin the paper to be sensitized on a table or board and apply the solution with a camel's-hair brush or a tuft of cotton (the brush is to be preferred). It is impossible to state the exact quantity of solution to use, as the rough or porous papers require more liquid than those which are well sized or of a smooth surface. The paper may be coated by gaslight, or lamp-light, without fear of fogging it. It is about as sensitive to light as platinum paper and, therefore, should not be unduly exposed to daylight.

542. It should be dried thoroughly in the dark-room, and unless it is to be used at once, stored in a tin tube containing calcium after drying. As the coating is very simple it is not necessary to sensitize large quantities of paper at once; furthermore for black tones the use of freshly-coated paper is essential. Sepia tones are best secured on old paper.

543. Printing

Printing. The greatest amount of skill required in this process comes in the printing, much depending upon its being done correctly. The image is only partly printed out, resembling platinum paper in this respect, in that the image is a grayish blue upon a lemon-colored ground. No great difficulty will be experienced, however, if you bear in mind that those portions of the iron salts which are affected by the light are the parts that will come out strong when the developer is applied. Wherever it is desired to have the picture tinted there must, in that same degree, be darkening of the iron salts. Damp paper will not give good black tones and, therefore, one should use the same precautions exercised when using platinum paper. After a few experiments the required depth of printing will be easily ascertained.