o
MAKING LANTERN SLIDES FOR IMMEDIATE PROJECTION1 JAMES ROSENFIELD Polaroid Corporation, Cambridge, Massachusetts
THIS talk will consist of a demonstration of a new photographic system that permits the snapping of a picture and its projection on a screen a few minutes later. The key to the system is a new film, the Polaroid Land Projection Film, which has a speed of 1000 (ASA equivalent), the fastest available on the market. This panchromatic film produces a virtually grainless image and can be projected to any size. It is easy to use, requiring no previous photographic experience, and because the net cost for a slide is about one-third that of a conventional slide, the new systemis of considerable interest in the field of visual communicat,ion. Essentially, all the user has to do is to snap the shutter, pull a tab, and in two minutes, lift out a transparency that can be mounted and projected a t once. The projected image is sharp and lifelike. Teachers have always found projected slides to be a valuable teaching tool, especially when explaining subjects far removed from a student's experience. For example, slides showing the setup for an experiment instantly hold the attention of the student and increase his understanding and interest. Ordinarily, the preparation of good slides is time-consuming and expensive and requires a darkroom and photographic equipment. There are several other advantages of the new procedure. The high speed of the film not only makes possible the taking of pictures in extremely low light levels, but also permits the use of small lens apertures to increase the depth of focus. There is available a Polaroid device called the Copymaker which fits all Polaroid Land cameras that permits copying documents, objects, photographs, book illustrations, titlesanything that will fit into the 11 X 14-inch space of the Copymaker's easel. In addition, the Polaroid slide mouut is made of plastic and snaps together without additional fasteners, tape, or glass. (Mr. Rosenfield then took a picture of a teacher in the front row, developed and Abstract of a. talk given st the 293rd Meeting of the New England Association of Chemistry Teachern, December 7, 1957, Wentworth In~titute,Boston, Massachusetts.
mounted it, and then projected it upon the screen in the elapsed time of three minutes.) As examples of the advantage of the on-the-spot development, we can cite the use made of it in a Boston hospital. Skin disease patients, brought before a class of 50 or more students, are photographed with closeup equipment. Pictures of the diseased areas are immediately projected, giving each student a closer look a t the affected area than is usually possible in such classes. Another example: I n Braintree, Massachusetts, the school safety officerphotographs both good and bad examples of street safety at crossings, as the students head for school. He uses the slides that same morning for his lecture to the student assembly. In another instance, a teacher took her class to visit a local science museum where there is a model of an atomic pile. Because ,the whole class had difficulty hearing her discussion a t the exhibit, she photographed the model and the next day projected the slides and discussed the details while the trip was still fresh in the minds of her students. To eliminate time-consuming instructions for apparatus setups, a science teacher photographed the apparatus before the actual experiment was performed in the laboratory. As there were several laboratory sections, the slides were used repeatedly, yet the instructor had to give his preliminary instructions only once. I n addition, the slides were used several weeks later as a review, again saving setup time. Closeups of experiments, made right in the classroom, can show such complicated procedures as the dissecting of a frog, and be used to let the whole class see the details usually visible only to those in the front row. Material written on the blackboard during one class session can he photographed and used again in a later section. Homework papers can he photographed and projected for discussion. The cost of recording such classroom materials is about 56 cents a slide. Considering the saving of the teacher's time and energy, this cost seems nominal indeed.
JOURNAL OF CHEMICAL EDUCATION
