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Condenser Enlargers
Enlarger and Easel Adjustments

Photography (Basic) - Introduction to photography and other graphic techniques
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When a diffusion enlarger is used, negative defects are not recorded as clearly in the print, compared to condenser  enlargers.  There  is  an  apparent  overall “softening” of the image sharpness and a reduction in image  contrast. Most of your negatives can he enlarged equally well with either a condenser or diffusion enlarger; however, for certain work the choice of enlarger may be an important  factor. The characteristics of a diffusion enlarger are as follows: It should be used for printing negatives that have been   retouched. It  subdues  negative  defects  and  grain. It has less image contrast than that produced with a condenser enlarger. It is not suitable for making large prints due to the softness of the image produced. Diffusion enlargers should be considered for use in portraiture and when the negatives have been retouched. CONDENSER-DIFFUSION ENLARGERS A  condenser-diffusion  enlarger  or  semidiffusion enlarger is a compromise between the two extremes of condenser  and  diffusion.  A  condenser-diffusion  enlarger uses a diffusion (frosted) bulb and condensers, or a diffusion  bulb  with  either  a  diffusing  glass  over  the condensers, or else one of the condensers itself acts as the diffuser. A condenser-diffusion enlarger has the advantages of a diffusion enlarger to reduce the effects of negative defects, silver grain structure and dust, and it also uses the  condenser  system  for  speed  and  uniformity  of  light. The enlargers in general use by most Navy imaging facilities are the condenser-diffusion type. They use frosted or diffusion bulbs with or without a diffusion screen  placed  above  the  condensers. ENLARGER LENSES As with a camera, the lens of the enlarger is the heart and should be high quality and reasonably fast. It is senseless to buy high-quality lenses for the camera, then nullify  the  quality  they  provide  with  an  inferior enlarging lens; however, a quality camera lens is not suitable  for  enlarging.  Even  a  moderately  good Table  11-1.–Enlarging  Lens  Focal  Lengths  for  Various  Negative Sizes Negative  size Lens  focal  length 35mm 50mm 120 (2 1/4 x 2 1/4) (6x6cm) 75mm 120 (2 1/4 x 2 3/4) (6x7cm) 105mm 4 x 5 inch 135-150mm enlarging lens is better for enlarging than most camera lenses. The focal length you use with an enlarger should be based on the size of the negative to be enlarged. (See table 1l-1.) Generally speaking, the focal length of the enlarging lens for a given negative size should be the same as a normal-focal-length lens used by the camera for the negative. While it is not necessary for the lens to cover the full area of the negative, the longer the lens focal length, the  less  magnification  at  a  given  lens-to-paper  distance; therefore, you must have several lenses of various focal lengths available for your enlargers when you want to make large prints from small portions of your negatives. Because an enlarger produces an image from a flat field (the negative) onto a flat field (the paper), depth of field  is  not  a  factor,  except  when  distortion  control (discussed later) is used. An enlarger lens can usually be used at large f/stops; however, when an enlarger lens is used at its maximum aperture, there may be some falloff of light at the edges of the circle of illumination. Therefore, an enlarger lens is usually stopped down one or two f/stops from wide open. Like a camera lens, when an enlarger lens is used at very small apertures, there is a loss of image definition due to diffraction. ENLARGING PROCEDURE The darkroom design, the equipment, and the arrangement for enlarging are basically the same as for contact printing. The safelights should be appropriate for the type of paper being printed. The size of the prints may require larger trays and greater amounts of solution, but they should be set up in the sink the same as for contact  printing. To  produce  good  enlargements,  you  need  good negatives, a clean enlarger, clean printing filters, correct exposure and development, and careful processing and finishing. Although most negatives can be printed by projection, there are a few desirable characteristics. A 11-11







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