Basic Photography Course

The amount of diffusing with a given material is

controlled by the distance of the material from the lens
of the enlarger and the density of the diffusing material.
Diffusing tends to lower image contrast; therefore, you
may need to use a higher contrast printing filter than
normally required for a given negative. The exposure
through the diffusing material should be about one third
of the total required exposure time.

To use dodging, burning-in, vignetting, and

diffusing effectively, you should make one full-straight
(uncorrected) print, using the basic exposure determined
with your test strips. Study this print and determine the
location(s) you are going to dodge, burn in, and so forth.
The application of these techniques may appear
time-consuming, but you will make professional-
quality prints that are rich in detail and mood.

MINIMIZING GRAININESS

As you know, most black-and-white photographic

images on film emulsions are made of fine grains of
silver. Because of this silver grain structure, enlarge-
ments, especially large ones, may appear "grainy." The
graininess of a print is a direct result of the graininess of
the negative and the degree of enlargement. The
graininess of a print, however, may be modified to a
limited extent during the printing stage by the following

techniques:

The diffusion enlarger should be used where

negative graininess is serious and objectionable in the
print.

The appearance of graininess in the print can be

reduced by using a rough, surface paper instead of a
smooth, glossy paper.

A diffuser used between the enlarger lens and the

printing paper helps subdue the appearance of grain.
Crumpled cellophane, fine mesh screen, or a piece of
nylon stocking can be used as a diffuser.

The enlarger can be set to project an image that

is slightly out of focus.

The permissible graininess in a print depends very

much on the viewing conditions. For a large display
print to be viewed from a relatively great distance, more
graininess can be tolerated as compared to a smaller
print held in a person's hand for viewing.

Figure 11-17.Distortion corrected by tilting the easel.

DISTORTION CONTROL

When you tilt the camera upward to make a

picture of a tall building, the vertical lines converge

and the building walls seem to be at the point of
collapsing. A view camera is equipped with
movements that allow the film to be parallel, or nearly
so, with the subject, in spite of the viewpoint;

however, most of the negatives you print probably are

not made with a view camera. Many negatives show
an undesirable, noticeable convergence of lines.

Changes in these images can be made by tilting the
head on some enlargers or by tilting the easel and
paper to correct image distortion (fig. 11-17).

Most enlargers have an easel separate from the

enlarger. Because the easel is separate, it can be
tilted by blocking it up on one end. A small
diaphragm opening (high f/stop) must be used to
increase the depth of focus to include both the part
of the easel nearest the lens and the part of the easel
farthest from the lens. Within the limits of what you
can keep in focus, you can correct some or all of
the distortion. With some enlargers, you can tilt the
negative carrier by propping up one side with one
or more coins.

11-20

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Basic Photography Course

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DOFMaster for Windows On-line Depth of Field Calculator DOFMaster for Mobile Devices On-line Depth of Field Table Hyperfocal Distance Chart Articles FAQ Recommended Books Support Contact Links Home As an Amazon Associate I earn from qualifying purchases.	contents <- previous page next page -> The amount of diffusing with a given material is controlled by the distance of the material from the lens of the enlarger and the density of the diffusing material. Diffusing tends to lower image contrast; therefore, you may need to use a higher contrast printing filter than normally required for a given negative. The exposure through the diffusing material should be about one third of the total required exposure time. To use dodging, burning-in, vignetting, and diffusing effectively, you should make one full-straight (uncorrected) print, using the basic exposure determined with your test strips. Study this print and determine the location(s) you are going to dodge, burn in, and so forth. The application of these techniques may appear time-consuming, but you will make professional- quality prints that are rich in detail and mood. MINIMIZING GRAININESS As you know, most black-and-white photographic images on film emulsions are made of fine grains of silver. Because of this silver grain structure, enlarge- ments, especially large ones, may appear "grainy." The graininess of a print is a direct result of the graininess of the negative and the degree of enlargement. The graininess of a print, however, may be modified to a limited extent during the printing stage by the following techniques: The diffusion enlarger should be used where negative graininess is serious and objectionable in the print. The appearance of graininess in the print can be reduced by using a rough, surface paper instead of a smooth, glossy paper. A diffuser used between the enlarger lens and the printing paper helps subdue the appearance of grain. Crumpled cellophane, fine mesh screen, or a piece of nylon stocking can be used as a diffuser. The enlarger can be set to project an image that is slightly out of focus. The permissible graininess in a print depends very much on the viewing conditions. For a large display print to be viewed from a relatively great distance, more graininess can be tolerated as compared to a smaller print held in a person's hand for viewing. Figure 11-17.Distortion corrected by tilting the easel. DISTORTION CONTROL When you tilt the camera upward to make a picture of a tall building, the vertical lines converge and the building walls seem to be at the point of collapsing. A view camera is equipped with movements that allow the film to be parallel, or nearly so, with the subject, in spite of the viewpoint; however, most of the negatives you print probably are not made with a view camera. Many negatives show an undesirable, noticeable convergence of lines. Changes in these images can be made by tilting the head on some enlargers or by tilting the easel and paper to correct image distortion (fig. 11-17). Most enlargers have an easel separate from the enlarger. Because the easel is separate, it can be tilted by blocking it up on one end. A small diaphragm opening (high f/stop) must be used to increase the depth of focus to include both the part of the easel nearest the lens and the part of the easel farthest from the lens. Within the limits of what you can keep in focus, you can correct some or all of the distortion. With some enlargers, you can tilt the negative carrier by propping up one side with one or more coins. 11-20 contents Basic Photography Course <- previous page next page ->	As an Amazon Associate I earn from qualifying purchases.
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