E. Stanley Thomas
I propose to describe a simple form of enlarging apparatus that I have had in use for anumber of months and which I believe will interest the readers of this magazine. The diagram will explain its construction quite clearly, I believe. A is an ordinary aluminum reflector, six inches in diameter; B is an ordinary incandescent electric light of sixteen candle power; V, a tin tube twenty inches in length, round at one end with a flange to receive the reflector as nearly light tight as possible and at the other end made square to fit closely over the edge of frame 1), which is an inoh wide. This frame carried the negative in two sets of grooves, one at the top and one at bottom These grooves are wide enough to hold two thicknesses of glass so that one can use a film negative between two clean glasses. The front of this frame or the side next to, the light, is fitted with pegs so that it takes its place against the frame of the camera just the same as the camera back which is removed for the purpose. The grooves in this frame are fitted with flat springs so that a single negative glass will be held firmly in place.
The camera is represented by E, and the easel upon which the paper is pinned is indicated by F. At the upper side of the tube near the light are a few small holes and in connection with some at the other end through on the under side, ventilation is secured. It is well to loosely drape a focussing cloth around the place where the reflector joins the tube, and again where the tube joins the camera so that there will be no leakage of light to strike the paper either at the join or through these holes.
The whole thing is placed on a table and joined up, the negative inserted and the focus secured on a piece of white card pinned to the easel. A trial strip of paper is exposed to get the time, and once found it is marked on the envelope of the negative for future reference. 1 generally stop down to U. S. 32, and the exposure is then from twenty to thirty-five for an 8x10 enlargement, and from forty-five to seventy-live minutes for a 16 x20. I append a few notes from my negative envelopes:
No. 211 Very dense, enlarged to 8x10; U. S. 16; 35 minutes.
No. 147. Rather dense, enlarged to 16 x 20; U. S. 32; 65 minutes.
No. 279. Average negative, enlarged to 16x20; U.S. 32; 45 minutes.
No. 301. Very dense, enlarged to 8x10; U. S. 32; 60 minutes.
No. 419. Fair negative, enlarged to 8 x 10; U. S. 16; 23 minutes.
My densest negative requires ninety minutes with U. S. 16 to obtain a 16x20 enlargement. I use East-man's C (soft) platino bromide, as I find it best for this form of light. When I mark the exposure time on the negative envelope the size of, the stop as well as the size of the enlargement is also indicated so that there will be no need to experiment when wishing to make an enlargement from the same plate at a later date. The camera I use is a 4x5 instrument fitted with a No. 2 Plastigmat of 6 1/4 in. focus.
I have made some very satisfactory enlargements with this simple piece of apparatus and would recommend others to try one on the same lines. It is not hard to construct, and the cost is very moderate indeed. The convenience of heing able to get all ready and then turn out the lights in the room and work without the discomfort of a dark room is made very simple by turning on an 8 candle-power ruby lamp lamp which hangs conveniently near. Fitting the lens with a cap glazed with ruby glass, even though it be a rough affair whittled out of wood and pasted over with black paper, would allow one to pin up the paper before making the exposure, and it would also serve as a ruby light in developing the paper by opening the lens to the largest stop. In developing by such a light one could simply swing the camera and its tin tube around so that the light from the lens falls where it is wauted. If the negative is a very dense one, remove it and then there will be nothing but the sheet of ground glass to obstruct the light before it passes through the ruby cap on the lens.
While this apparatus is not the most advisable where a large amount of work is contemplated, on account of the length of exposure required, it will be found entirely satisfactory to the average worker who makes but few enlargements from time to time. In fact, the length of exposure is an advantage, permitting, as it does, perfect control by shading or otherwise dodging the print during exposure.