The audio-visual handbook (1942)

76 The Audio-Visual Handbook the object to be projected on the screen. In those cases, color should be used if possible. Some teachers who have become experienced with the tinting of slides have found it advisable to order uncolored positive prints and apply the appropriate tinting. The process is not difficult to one who is at all artistically inclined, but is one which requires a high degree of patience and care. One of the paramount considerations in arranging a collection of slides, whether for individual or school use, is that of suitable filing or housing of materials. In all cases, slides or other visual aids should be so filed as to be accessible with the least amount of effort. The indexing system used, regardless of whether it may be alphabetical, by subject, or numerical, should be clear to all who make use of that set of materials. There should be a complete list of all slides available, and a copy of this list should be accessible to each teacher using the slides. There are many convenient systems for filing slides so they will be readily accessible to the user. One of the most convenient forms is a large cabinet containing upright racks in which the slides are stood on edge and may be lifted in and out of the racks with ease. Furthermore, the slides are so arranged that the teacher may look through them without removing them from the case. These outfits are reasonably expensive but are worth the cost in those situations where they can be afforded. The usual plan of filing slides is to prepare small boxes or drawers approximately the dimensions of the slide in which the slides stand side by side. Filing outfits of this sort may be purchased or may be constructed in the carpenter shop or by the manual training class. The proper care and repair of slides is essential to keeping the service in working order. Slides should be handled by holding the edges, and not by grasping the face of the slide with the hand. Each thumb or finger print on the surface of the slide itself will tend to reduce the brilliance of the slide and will be projected to the screen as evidence of carelessness. The surfaces of the slides should be washed whenever they become dirty through use, and the binding tape around the edges of the slides should be replaced whenever the corners become broken or frayed. The binding tape protects the inside of the slide from dust and moisture, so it should be in good condition at all times. In some instances the cover glass will be broken in handling the slides. It is a very simple process to remove the broken glass and replace it with a new one. However, if the glass on which the picture is printed becomes broken, it is very difficult to repair it in such a way