International photographer (Jan-Dec 1935)

Twenty-eight The INTERNATIONAL PHOTOGRAPHER April, 1935 NOTES ON COLOR (Continued from Page 15) First Development: Water (125° F.) 2000 ccs. Metol ------- Hydroquinone Sodium Sulphite (Anhydrous) Potassium Bromide Ammonia (Spec. Grav. o.9) Dissolve all chemicals 65T., and add ammonia 13 grams 4 grams 100 grams 53/> grams 30 ccs. in the order given, cool to if ammonia of stronger spe cific gravity only as available, either dilute same or use proportionately less according to the strength. Developing time in the above bath with correctly exposed subject is 2J/2 to 3 minutes at 65°F. This developer will keep in a tight stoppered bottle. 2. Wash two minutes. 3. Bleaching Bath (Reversing) : Potassium Permanganate 3 grams Sulphuric Acid ----- 10 ccs. Water ------- 1000 ccs. Bleach until image is clearly visible. Time: about 4 minutes. Bleaching is completed when the image is clear and there is no veiling. A weak light can be turned on after 2 minutes for inspecting negative. 4. // ash for about 2 to 3 minutes in running water. 5. Rinse for 2 minutes in following clearing bath. Clearing Bath (2\A'/, solution of Sodium Bisulphite): Water 1000 ccs. Sodium Bisulphite ---- 25 grams 6. Rinse after clearing. 7. Expose film to strong artificial light (100 watt lamp) for about 3 minutes. The film is then redeveloped in any good metol-hydroquinone bath. Film can be under, but not over-exposed. The following may be used : Water (125°F.) ---- 4000 ccs. Metol -------- 4 grams Sodium Sulphite (Anhydrous) 200 grams Hydroquinone ----- 18 grams Sodium Carbonate (Anhydrous) 75 grams Potassium Bromide 4 grams Time of final development: 3 to 4 minutes at 65°F., or even 6 minutes if required. When image is thoroughly darkened, development is complete. 8. Rinse thoroughly. The film is now fixed and hardened and given a final washing. Use weak acid fixing bath . . . wash in running water 20 minutes . . . wipe dry with a viscose sponge to avoid water-marks. When DuFayColor pictures have been completed, they are ready for use. There are many ways of enjoying their beauty. The most satisfactory method of viewing color film is of course by means of projection. The film strips may be used in the projector as film slides, or better still, each picture can be cut apart and bound between two 2x2 inch cover-glass slides. The glass slides protect the film from danger, and make a most convenient method of not only preserving the pictures but showing them as well. The Leitz Umino projector is equipped to handle the pictures either as film strips or glass slides. Stereo enthusiasts will be interested to know that by means of the Leica Stereoly attachment, perfect stereo pictures can be made in full color, using the DuFayColor film. As is commonly known, the Stereoly attachment is a simple yet effective device which merely slips over any one of the 50 mm. Leitz lenses of the Leica camera. New avenues are opened to the Leica owner who desires to combine his stereo and natural color activities. Imagine the thrill of seeing pictures in full third-dimension AND natural color! This is truly the dream of thousands, and is now about to be fully and satisfactorily realized. To those who have not as yet become interested in color, it In W*?rld~(A)i2* Usve Cff^cts in Dayxirn* "Fv^ Scvn^s ftif fused. Fv7cus. an A many ^rb«r sFfvcrs With any Camera •" In any Ulirnare GeorcjG H. ScHeibe ORIGINATOR OF EFFECT FILTERS 1927 WEST 78th ST. LOS ANGELES. CAL. is strongly suggested that they try just one roll — on seeing how easily and simple color photography is with DuFayColor process, they will no longer be content to make black and white pictures. MINIATURE CAMERA PHOTOGRAPHY (Continued from Page 19) simply due to incorrect mixing of the developing solution, a step which is usually not given the proper attention. Mixing a developer entails the bringing together of various chemicals in the same solution, and this must be accomplished properly if the correct results are to be produced. With many formulas the ingredients are listed in the order in which they are to be dissolved ; however, by adhering to the following general rules a developing solution will be properly prepared : 1. The alkali, or accelerator , should not be dissolved with the developing agent before some preservative (sulphite) has been added. The alkali increases the developing agent's affinity for oxygen, so that if the sulphite is not added first to absorb the latter, the developing agent will undergo a degree of oxidation, according to the time it is allowed to remain in solution with the alkali before the sulphite is added. 2. Do not add a second chemical to a solution until the first has been completely dissolved. 3. In general do not dissolve the developing agents in water over 125°F., for they are likely to undergo undue oxidation. P-diamine is an exception to this rule. It can be dissolved practically in boiling water without ill effects. Three simple rules, but nevertheless if they are insurance against avoidable trouble. adhered to W EVERYTHING W W PHOTOGRAPHIC^ fcTH Mem M J A A ^7 for Professional and Amateur \ V New and used. Bought, sold ' W rented and repaired. Designers and manufacturers of the ^ H.C.E. Combination Lens ^L Shade and Filter Holder . ^k for any size lens J ^^L Send for bargain catalogue A ■ ^^ Hollywood Camera ^H ^k Exchange ^f ^k 1600 Cahuenga Blvd. ^k ^L Hollywood ^H "•' A Tel.: HO 365! ^ W Cable: &! JAjH f fllll vfl ^k HOCAMEX ^| A^ ^k ^H YV'V Please mention The International Photographer when corresponding with advertisers.