This section is from the book "Complete Self-Instructing Library Of Practical Photography", by J. B. Schriever. Also available from Amazon: Complete Self-Instructing Library Of Practical Photography.
Surfaces And Grades. Cyko is made in five surfaces and three grades. The surface is represented by the number on the end labels, the grade by the color of the label. In each grade will be found a variety of surfaces. Choose the surface most suitable and which will harmonize with the subject of the picture. Select the grade according to the quality of the negative. A weak or thin negative lacking in contrast, requires a contrasty paper, such as Blue Label Cyko. For a normally exposed and developed negative use Yellow Label Cyko. For contrasty negatives use Brown Label Professional Cyko. The last named, however, is intended principally for photographers who have the necessary experience and knowledge to handle a soft-working paper.
Surfaces, Weights And Grades Of Cyko. Cyko No. 1 is matte surface.
Cyko No. 2 is semi-matte surface.
Cyko No. 3 is glossy surface.
Cyko No. 4 is rough surface.
Cyko No. 6 is studio (velvet surface).
Grade And Color Of Label. Blue Label indicates contrast. Yellow Label indicates normal.
Brown Label indicates professional (for soft effects).
Double Weight. Double weight Cyko is furnished in semi-matte, studio, rough and glossy surfaces, and contrast, normal and professional grades. Double weight papers require no mount.
The Selection Of Light. Cyko prints, like other gaslight papers, may be made by using daylight for exposure. Select a north window, if possible, as the light from this direction will be more uniform. The paper, being quite sensitive to daylight, should be handled in subdued light, as otherwise it might fog. Proper precaution should be taken to pull down the window shades and darken the room sufficiently during manipulation. If the light is too strong for printing, it should be diffused or subdued by the use of several thicknesses of white tissue paper. Daylight is extremely variable, and for that reason the use of artificial light is recommended, as it varies less in intensity.
903. The Welsbach light is usually preferred to other illuminants, on account of its great intensity. The mantle should be in good condition and the gas pressure uniform, so that the light will vary in intensity as little as possible.
904. When gaslight is used for printing, a very convenient arrangement is a by-pass valve which controls the supply of gas to the burner. When this valve is closed only enough gas passes to keep the burners lighted, and the exposure is made by opening the by-pass when the exposure is to be made. This arrangement can be still further simplified by having a spring to close the by-pass, and a cord to open it when ready to make an exposure.
905. Ordinary gaslight, while not as strong as the Welsbach light, has the advantage of being more uniform, if the quality of the gas does not vary. With the Welsbach light the intensity depends, to a large extent, on the condition of the mantle. Ordinary gaslight is satisfactory and convenient for printing, especially for small negatives up to and including 4x5. Larger negatives, particularly if they are at all dense, require too long an exposure.
906. The light from a kerosene lamp is also satisfactory. A large, round-wick kerosene lamp gives nearly the same quality of light as a flat flame gas burner. The wick must be well trimmed, and the flame should be kept always at the same height when printing.
907. For the professional who has a large number of prints to make daily - especially the commercial photographer - the Cooper-Hewitt light (mercury vapor) possesses decided advantages. The Cooper-Hewitt Company sell a set of lamps for this purpose. When using the Cooper-Hewitt lamp, a good method is to partition the room, to have the lamp enclosed, cutting out a square opening in the partition. When development is in progress, by means of a carriage arrangement, this opening can be covered with a piece of postoffice paper, or orange glass, and uncovered when an exposure is to be made.