In practice it will be best to become familiar with the use of about three stops, say the full aperture (perhaps F/5.6 or F/8), F/16, and F/32.
For judging long exposures, the use of an actinometer (issued in many inexpensive forms) is helpful.
A telephoto attachment increases the photographer's power of rendering distant details on a large scale. The results are greatly superior to enlargements of a small plate. It is, however, useless in a wind, unless the camera is specially supported, and is otherwise rather tricky to use. The traveller is strongly advised to master its management at home. It should be adjusted by the maker to the camera for which it is intended.
Unless a photographer's dark room can be had the developing of the bulk is best left until the return home, but tests should be made to see that the exposures are correct. A piece of ruby fabric or ruby paper tied over an electric light will give a safe light after dark, and 'Scalol' or some such one–solution developer which requires merely the addition of water, will give all that is needed for developing. For fixing use 4 oz. hypo to a pint of water.
In warm climates, use cold water. If it is not cool enough, the gelatine of the negatives may give trouble. In that case, get colder water, and use an alum bath. If water is precious, plates can be sufficiently washed by moving them forward in succession, through half–dozen soup plates filled with water.
If habitual use is not made of tabloid developers, &c., it is advisable to have some in reserve, for use in the case of broken bottles and spilt solutions.
Useful notes and maxims.
An over–exposed plate gives no dark shadows in the print.
An under–exposed plate gives no high lights. When in doubt, choose the risk of over–exposure.
To test the safety of your camera—Half draw the shutter, and expose part of the plate in the camera, in the sunshine, without uncapping the lens, and develop.