International photographer (Jan-Dec 1934)

Twelve T h INTERNATIONAL PHOTOGRAPHER December, 1934 Miniature Camera Photography By Augustus Wolfman The Story of the Enlarger [N the enlarger, or projection printer as it is I'SHHi termed lately, some expedient must be embodied to insure that the negative is evenly illuminated. The two things usually employed are the diffuser and the condenser. The diffuser consists of a ground glass, Bashed opal glass, or similar material, placed between the light source and the negative. It breaks up and scatters the light coming from the former so that many rays from all directions Screen picture, taken by R. E. Stichler. Hypersensitized DuPont Superior film was used. Exposure: 1/10 sec. at f:3.5. light up the negative. This is a great help for negatives which contain small mars for diffused light has the ability of minimizing the tendency of defects, as well as coarse grain in the negative, to show up in the print. Diffused light is also helpful when printing contrasty negatives ; it produces soft results. Quite the reverse the condenser tends to produce brilliant contrasty prints, and also easily shows up mars on the negative, in the print. It usually consists of two lenses each of which is flat on one surface and convex on the other, and in the enlarger they are placed so that their convex surfaces face each other. The size of the complete condenser is governed by the diagonal of the negative, its diameter being slightly larger than the latter. It gathers the rays from the light source and converges them into a cone the apex of which is approximately at the diaphragm of the lens. The condenser is placed in the enlarger close to the negative and in some projection printers it rests on the negative during exposure, acting as a pressure plate. If a clear lamp were to be used as the light source, its filament would be focused by the condenser into the lens. To overcome this diffusion is employed in conjunction with the condenser. There are also other advantages of this practice. The diffuser will minimize the ability of the condenser to reproduce slight defects on the negative in the print ; it will tend to remove the effects of aberrations in the condensing lenses, and also reduces the necessity of the lamp being adjusted every time the lens is racked in or out. In a condenser enlarger there is usually a screw or other device present by which the lamp can be loosened and moved up or down. When the enlarger is obtained it is best to adjust the light, and once this is accomplished it will be found that it is not necessary to re-adjust the light unless extreme enlargements are to be made. The diffuser takes a lot of credit of eliminating the necessity of the constant adjustment of the light in a condenser enlarger. A negative is placed in the latter, and about a three or four times enlargment projected on the easel, upon which a sheet of white paper has been placed. The negative is carefully focused, then removed, and it is observed whether the area on the white sheet is evenly illuminated. If not, the lamp is loosened and moved either up or down until the area projected on the white paper is evenly lighted. The lamp is then secured. No further adjustment will usually be necessary for the ordinary run of enlargements. Many enlargers employ the flashed opal lamp in combination with the condenser. Others use a sheet of ground glass or flashed opal glass. A great number of miniature camera photographers are turning to the use of the Photoflood lamp, because its intense illumination enables them to use slow contact papers, which are supplied in a greater number of contrasts than bromide paper. Although the usual Photoflood lamp is frosted, it is now possible to obtain these lamps made from opal glass which effectively diffuses this brilliant light source. There are a large number of reliable miniature enlargers on the market, and most will be found to employ the combination of a condenser with a diffusing medium. One enlarger enables a single and double condenser, and an opal screen to be interchanged. The opal screen together with an opal lamp is used when soft prints are desired ; the double condenser is used for contrasty results, and the single condenser and opal screen, are employed for negatives of average density. The question of the lens on the enlarger sometimes arises in view of the fact that many miniature camera photographers use the lens of their camera on the enlarger. In enlarging a good anastigmat is ideal, to insure a flat field, and the quality of the lenses supplied with high grade miniature cameras cannot be questioned. The objection is sometimes raised to this practice that the continuous use of radiant light, and heat, may have a harmful effect on the cement of the lens. The only advice that can be given on this subject is that if the photographer can afford it he should obtain his enlarger with a separate lens provided for that purpose. At least the high grade expensive lens of the camera will not have to be handled so frequently. Many miniature camera photographers still have all their printing done by the commercial finisher. It cannot be expected that the best results be produced by the finisher because he first of all cannot give individual treat(Turn to Page 24) Kinema Krafts Kompany calling AMATEURS and PROFESSIONALS Who want fresh 35mm. EASTMAN or DUPONT Gray Backed Negative. Price— $.02Y2 per foot 6510 Selma Ave. Hollywood, Calif. GLadstone 0276 Please mention The International Photographer when corresponding with advertisers.