745. Developing

Developing. The ordinary methods for developing, fully described in Volume II, apply as well to the development of plates exposed through the microscope. Where one is not equipped with the paraphernalia necessary for the regular dark-room, the outfit described in this chapter, under the heading of Dark-Room, will be required.

746. Owing to the fact that for all color slides, especially bacteriological work, the orthochromatic plate must be used, and as this plate is sensitive to all kinds of light, extreme care must be exercised in providing an absolutely light-tight dark-room, and the developing must be done as far away from the developing light as possible. For convenience, the trays should be used a trifle larger than the plates to be developed. Where the regular developing outfit is not at hand, three trays may be employed. In the first tray place the developer; in the second, provide plain water, and in the third, hypo or fixing solution. Hard rubber trays are preferable for developing, their lasting qualities being far superior to all others, and there is less danger of spots or stains.

747. While any of the developing formulae in Volume II may be applied to this work, yet it is advisable to employ the formula supplied by the manufacturer of the brand of plates you are using. A good, all-around developer for this work will be found in the following formula:

For use, take 2 ounces of this solution and dilute with 2 ounces of water. This developer has no poisonous influence upon the skin and will not stain the fingers.

749. Hypo Fixing Bath

Hypo Fixing Bath. The hypo fixing bath is prepared as follows:

Solution A: Dissolve the hypo in the water. Solution B: Dissolve chrome alum in the water. Then, carefully add the sulphuric acid, constantly stirring while adding. When the chrome vii - 17 alum is dissolved, pour Solution B into Solution A. This solution remains clear even after continued use, and should be thrown away when it becomes discolored.