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. This last method of negative enlarging, as previously stated, requires two large plates, and while it is a trifle more expensive, yet, for the very finest results it is the best, less grain being produced in this way than if the transparency were made from the original negative by contact and then enlarged from this small transparency.
Making Transparencies On Film. Films may be employed for making a small transparency, either from a film or glass negative, and the film may then be enlarged on a glass plate, the same as though a glass transparency were used.
Making Small Size Negatives From Large Ones. For this work only the regular camera with the regular lens fitted to it will be required, providing it will make a picture as large as the size desired to reduce to. In this case, when reducing, a lens as large as that used in making the original is not needed, but only one large enough to make the size picture required. For example, to reduce an 8 x 10 negative to 5x7, any lens that will cover a 5 x 7 plate may be used.
Copying The Negative. In making a reduced negative from one of larger size, instead of making a contact transparency, copy the negative in the same manner as described later for copying negatives for lantern-slides, thus making a small transparency of the size desired. From this small transparency make a small negative by contact, and develop in the ordinary way.