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.
833. Consequently the best results are obtained by using our formulae, as published. If more delicate effects are desired, add more water in diluting the developer for use; it causes a little slower development, but its advantage will be seen in the finished negative.
834. This brand of plates is intermediate in rapidity, between Hammer's Slow and Hammer's Extra Fast, combining the great latitude of the Slow Plate with enough rapidity for all ordinary purposes, except where a very short exposure is required or the light is not good.
835. A large number of photographers use this plate for view work, while many commercial workmen prefer it to all others. The grain is fine and the latitude good. Any degree of softness or contrast may be produced on this plate, by noting the principle mentioned in the article about Slow Plates.
836. If the Slow Plate is too slow and the Extra Fast is too rapid, then this is the plate that you want - easy to work and an ideal plate, unless you wish to make snap-shots, in which case see article regarding Hammer's Extra Fast.
837. For the benefit of the beginner, we give a table showing the approximate exposure required on Hammer's Extra Fast Plates, on various subjects and in lights of various strength. This is (10 a. m. to 2 p. m.) in May, June and
July. In other months (and earlier and later in the day) the light is not so strong.
838. Of course, the temperature of the developer and the quality of the lens bring in variations that we have not space to consider here, but we wish to give some idea about the exposure required on different subjects under various conditions of light. (Use No. 8 diaphragm.)
839. With the Orthochromatic Extra Fast Plate, without a screen or a ray filter, the exposure is the same as given below. If a screen or a ray filter is used the exposure will have to be increased from four to eight times, according to the darkness of the filter.
Exposure Table for Hammer Extra Fast Plates, in
..........................Part of a Second----------------
1 - 250
1 - 200
Snow, sea and sky - distant view ...................................
1 - 125
1 - IOO
Semi-distant views and light objects..................
1 - IOO
Average scenes, near views and buildings ...........................
1 - 25
Groups, dark objects, portrait - out-of-doors .....
Views - heavy foliage in foreground ........................
1 - 25
1 - 4
1 - 4