Alternative Films for Making - Presentation Slides for the Occasional User Harold R. Hunt, Jr. Georgia Institute of Technology, Atlanta, GA 30332
As alternatives to the well-known Kodak Kodalith film for making presentation slides, we would like to suggest the use of two less well-known films, Kodak Technical Pan Film 2415 and Kodak Precision Fine Film LPD4. Both films are canahle of makine excellent oualitv slides with minimum efiort, and for t h e occasional user each film offers certain advantages over the Kodalith-Diazochrome combination which was recently described in THIS JOURNAL.^ Kodak 2415 film is a fine-grain, high speed film that produces dense, high-contrast negatives when processed in Kodak D-19 developer. One advantage of 2415 over Kodalith is the availability of 2415 in 35 mm, 36-exposure cassettes as well as in 150-ft hulk rolls,2 while Kodalith is available only in 100-ft rolls and sheets. A second advantage is the greater exposure index, 100 for 2415 versus 6 for Kodalith. This permits a faster shutter speed and smaller f stop for 2415, resulting in increased depth of field. The 2415 negatives may be mounted for use as negative slides, copied on 2415 to produce positive slides, or copied on Diazochrome film for colored slides. Kodak LPD4 is a slow (exposure index 3.2), moderately high contrast film which produces positive slides directly with conventional processing using Kodak D-11 developer. I t is supplied in 35 mm X 150-ft bulk rolls,3 hut not in 36exposure cassettes. The speed and simplicity of preparing positive slides is the chief advantage of LPD4 over Kodalith. Thirty-six positive slides can easily be produced in 2 h or less. Pamphlets are available from Kodak which give recommended storage, exposure, and processing guidelines for 24154and LPD4.5 However, the procedures which give optimum results for us are briefly described below and should serve as a starting point for anyone wishing to try these films. A
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2515 Negatives
A 35-mm. single lens reflex camera with built-in light meter is mounted on a homemade copy stand similar to the one described elsewhere.' Even illumination of a 12 X W i n . area on the copy stand base is produced by two 150-w reflector flood lamps placed 34 in. between filaments, with the filaments raised 12.5 in. above the copy stand base. Although the nominal exposure index for 2415 film is 100, we have obtained better results using a rating of 200. The proper exposure is determined by setting the camera shutter and film speed dials t o 1/60 s and ASA 200, respectively. Next, the copy area is covered with neutral gray cards, the flood lights are turned on, and the exposure is determined using the built-in light meter. An exposure of 1/60 s a t f8 is normal with our equipment but may vary with other copy stands and light sources. All exposures are made using the same shutter speed and aperture setting if only close-up lenses are used in conjunction with the prime camera lens, hut if hellows or extension tubes are used a new exposure reading should be made each time the camera-lens distance is changed. The exnosed film is loaded into a davliaht - " ~rocessine . " tank in a darkroom or changing bag. The film is developed for 4 min at 20°C using Kodak D-19 developer, with agitation for
5 s a t 30-s intervals. Yext, the film is rinsed with water then fixed for 4 min in Kodak fixer. The film is again rinsed with water. then bathed for 30 s in Kodnk Hvno Clearine Aeent. in ally, the film is washed for 5 min under running water, and then hung up to dry. If desired, a brief immersion in dilute Photo-flo may be used following the wash to prevent water spots.
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Diazochrome Posltlves For a small number of slides, it is convenient t o expose and d e v e l o ~them individuallv rather than in s t r i ~ susing a printi!;g frame as described elsewhere.! Other than the 2'415 negatives and 1)iazochromc shert film, all that iu needed is a 506-w Kodak Carousel projector, a ~ e p or e similar slide mount having clips or edge guides for holding the negative and diazochrome film frames in alignment, a 125- X 65-mm crystallizing disk, a 115-mm porcelain desiccator plate with feet, a 5-in. or larger watch glass, and concentrated aqueous ammonia. The diazocbrome sheet film is first carefullv cut into pieces the size of a single 35-mm frame (approximately 1%X 'I2 in.) using scissors or a paper cutter, in dim light. These cut film pieces should he stored in a lightproof container such as an emDtv bulk film canister until needed. Next. a 2415 neaative &d-a piece of diazachrome film are placed in the slide mount with their emulsion sides facing each other."he slide is then placed in the projector withthe negative facing the light source and given a trial exposure of 20 s. hi ammonia vapor developing bath is prepared for use by pouring a small quantity of fresh concentrated aqueous ammonia into the crystallizing dish, inserting the desiccator plate, and covering the apparatus with a watch glass. The exposed diazochrome film is then removed from the slide mount and placed on the desiccator plate to develop in the ammonia vapor for a t least 5 min or until maximum color intensity is obtained. If necessary, the exposure time may be varied to give optimum results. Increasing the exDosure reduces thecolorintensity of the diazochrome slide. The developed slide is mounted in a 2 X 2-in. slide mount. 2415 Positives
Excellent quality positive slides may he prepared by copying the negatives onto 2415 film using a 35-mm camera equipped with a copy attachment with a film strip adaptor. We have found the Spiratone Vario-Dupliscope system7 with calibrated light source to be satisfactory for this purpose. Each negative is copied according to the procedure
' Wright, N. A,, and Blevins, D. D., J. CHEM.EDUC.,61, 800 (1984).
Kodak Technical Pan Film 2415. CAT 129 9916. TP 651. Kodak Precision Line Film LPD4. CAT 157 8327. SP 421. "KodakTechnicaiPan Film 50-1 15." Kodak Pamphlet No. P-255, Professional and Finishing Markets Division, Eastman Kodak Company, Rochester, NY. "Kodak Precision Line Films LPD4 and LPD7," Kodak Publication No. G72, Graphic Data Markets, Eastman Kodak Company. Rochester, NY. When the emulsion side ofeither type of film is viewed, the film tends to curl toward the observer. Spiratone, Inc., 135-06 Northern Blvd., Flushing, NY.
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Volume 62
Number 12 December 1985
1097
provided with the copy attachment, using an exposure index of 200. The exposed 2415 film is then developed, fixed, and washed as described previously. After drying the film, the positive frames are cut apart and placed in 2 X 2-in. slide mounts. LPD4 Posltlves Our experience indicates that this film is even slower than its rated exposure index of 3.2, which is below the smallest film speed setting that is available on many built-in light meters. However, we have found that accurate exposure measurements may easily be obtained using the following procedure. After loading the camera with LPD4 film, the film speed and shutter are set to ASA 25 andl/s s, respectively. Next, the copy area is covered with gray cards, the lights are turned on, and the diaphragm setting is determined using the camera light meter. The actual exposure is ohtained by multiplying the indicated exposure time by 40. A typical reading with our equipment is '18 s a t f8, which indicates an optimum exposure of 4018 s (or 5 s) a t f8. T o obtain
1098
Journal of Chemical Education
these long exposures, the shutter is set on "B," a cable release is used to minimize vibration, and a timer or stopwatch is used to measure the time that the shutter is open. The exposed film is loaded into a daylight processing tank as usual and developed for 2 min in Kodak D 11developer with brief agitation every 30 s. The fixing and washing steps are the same as those given for Kodak 2415 film. After it is dried, the film is cut and mounted, and the direct positive slides are ready for use. DlSCuSSIon Kodak Precision Line Film LPD4 and Technical Pan Film 2415 have been shown to be excellent alternatives to Kodak Kodalith film for quickly and easily making presentation slides. The 2415 film produces professional quality negative slides which may be converted to positives or diazochrome slides by conventional techniques. The LPD4 film produces good quality direct positive slides with a minimum investment of time and effort.
