APPLICATIONS OF THE SMALL CAMERA Lantern slides are a valuable aid to teaching, especially when the slides are home-made and the subjects well chosen. Ways are s h m by which the small camera may be applied to the making of lantern slides. A method is described for making microphotographs by use of the small camera.
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In many schools the purchase of expensive photographic equipment is impossible. However, the uses to which photography, in its various phases, may be put are already well known and appreciated. T h e accompanying suggestions are for those who would like to use photography in their work hut feel that they cannot do so from a financial viewpoint. The work proves very interesting and may take the form of a hobby as well as being of value. In many cases a good student may he allowed to do the work as a special assignment. The lack of experience in photographic work need he no deterrent, for the person who is able to follow directions and possesses a reasonable amount of manipulative skill can secure 1 good results. The author Frcuns 2 had no previous experiFRONT AND R E A R VIEWS OF SUGGESTED ARRANGEence in microscopic work MENT OF CAMERA AND BOX and very little in photography, yet he has obtained a number of good slides with a very small percentage of failures. The material contained in the suggestions below may not be entirely original, but is offered for the value i t may have. The author has found 1359
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work of this kind t o be very interesting and well worth the cost and effort, both as a hobby and as an investment toward better teaching. Those who are unacquainted with photography will find that working directions for general procedures are easily mastered. Lantern Slide Making The making of a lantern slide is essentially the same as producing a photographic print, the differencebeing that the positive image is placed on glass instead of on paper. Slides may be produced from any suitable negative by direct contact printing if the negative is of the proper size. The primary object here is to explain the use of the small camera in obtaining suitable negatives for the making of slides. For slides of scenes and distant objects the camera may be used as usual, the slides being printed from the resulting negatives. However, often i t is desirable t o copy some small object, such as a flower, insect, or a small drawing or diagram of a process from a paper. In this case, the average small camera will not produce a sharp image a t such close range. Short focus attachments are on sale but even these a t times do not permit of close enough focusing. This trouble may be overcome by using the small camera fitted into a box which will have the effect of lengther&g the bellows and therefore permitting a shorter focusing range. An ordinary wooden box may be built, about half as deep as the length of the camera bellows. The front of the camera, with film holding back removed, is fitted into the
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FIGURE 4.-$RRANGEMENT OP CAMBRAAND MICROSCOPE FOR MAKING
M~cnoPnoToonA~~s
front of the box and in the back is fitted a holder for a lantern slide plate. This holder may be bought for very little from a dealer. Of course any other sort of negative holder could be adapted to the use, but lantern slide plates make good negatives since they are of the correct size for direct printing of positives. To make a picture, the subject is arranged, properly illuminated, and the focusing done by placing a sheet of ground glass in the back of the box in place of the plate holder, the focusing then being done by extending or closing the bellows of the camera. The plate holder is then replaced and the exposure made. Good illumination can be obtained by the use of two bulbs, one on either side of the camera and directed toward the subject. The time of exposure will depend on distance and degree of illumination and will be found by experience. Using two 300-watt bulbs for copying printed matter, the exposure will be in the neighborhood of five to fifteen seconds. Figures 1 and 2 show front and rear views of the arrangement suggested. This box is rather crude and can no doubt be improved upon, especially if it could be made flexible to permit of changing the depth. A sample picture made by means of the camera as shown is given in Figure 3. The development and fixing of the negatives will need to be done in a dark room of course, or the work may be done a t night. Instructions as to development formulas and other helpful material may be obtained from the Eastman Kodak Co. free of charge. Their booklet on "Lantern
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Slides, How to Make and Color Them" is very helpful. This gives instructions for the printing of the slides from the negatives. If the negative to be used is larger than lantern slide..size, a print may be made and then copied or the negative may be illuminated and photographed by the arrangement described, the result being the positive desired. A convenient method of illuminating a negative is to place it in front of a sheet of ground glass or parchment paper which is illuminated from behind. There is no doubt that many home-made slides have a value greater than those bought from a dealer, whereas some can be obtained which could not be bought. The cost is much less also. The author has produced slides by the above method a t a cost of approximately fifteen to twenty cents each, including the cover glass, binders, and chemicals. The camera used in the above work was a Hawkeye No. 2A with single lens. Any type which has a bellows which can be moved back and forth
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would serve as well. Often a good focusing camera may be bought very cheaply from second-hand dealers. Microphotography In making up some slides for class use it was thought desirable to have some microphotographs of crystals, fibers, and other subjects. Upon experimenting with the idea it was found that when the microscope is in focus for the eye, the fixed focus camera is also in focus if placed with the lens against the eyepiece of the microscope. The accompanying photograph, Figure 4, shows the arrangement used. If there is doubt about the focus being correct i t may he checked by removing the back of the camera and substituting a piece of ground glass, upon which the image will show. For illumination of the sample, an ordinary 60-watt electric bulb was used. The accompanying prints (Figures 5, 6, 7, and 8) show crystals of potassium iodide, sodium nitrate, and sodium chloride, and fibers of cotton, respectively. These photographs were made on roll Hm in the kodak and required about a fifteen-second exposure using a 60watt bulb. The negatives were then used for printing lantern slides. In order to obtain the crystals for photography, drops of the very dilute solutions were placed on glass plates and allowed to evaporate very slowly. Many other interesting subjects for microphotography will suggest themselves.
