Yashica Twin Lens Reflex Guide - Focal Press January 1964 Page 32 / 55
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The Choice of Colour Film
Making your choice between colour reversal or negative film (in spite of the various uses that can be made of either type
of material) remains an individual question.
First there is the way you want to see the result, as a colour print or as a colour transparency. The print has no doubt much
to commend itself. It is easily shown, stored and carried about. The transparency calls for the aid of a viewer or projector.
Next, the cost of a colour print is about three times that of the transparency. This may at times be mitigated by the fact that
from unsuitable negatives no colour prints need or can be made. The transparency user, however, has additional outlay in
the form of a viewer or projector with screen (in most cases both).
Yashica reflex transparencies made on size 120 film need projecting in a large-size projector which, takes 2 ¾ x 2 ¾ in.
slides. Alternatively, you can cut down the transparency to fit 2 x 2 in. miniature slide frames (1 5/8 x 1 5/8 in. super
slides).
The Yashica Reflex 44 models (#) yield 1 5/8 x 1 5/8 in. transparencies directly. With the Yashica 635 model, used with
35 mm. film, you get 24 x 36 mm. transparencies for mounting in 2 x 2 in. standard frames.
A final point to consider is the quality. The transparency will record each colour and its brilliance in full. Held to the light
or projected on a screen, the brightness range, which may be 100 : 1, is fully or almost fully retained. It shows colours
brilliant with great depth and realism. The colour print can at its best reflect only four-fifths of the light failing on it and
even the darkest tones reflect about one-twentieth to one-tenth, so that the full range is no more than 16 : 1. While the
colour print is, by necessity, duller than the transparency, it is only fair to say that the eye soon adjusts itself to the reduced
brightness range, and subjects without great contrasts will be very satisfying.
From the point of view of convenience, reversal film has the advantage that it directly gives finished colour pictures of
high quality and is still capable of producing colour prints as well. For the maximum versatility and control in print
making, however, negative film is superior.
Filters for Black-and-White Film
By its nature, a black-and-white film can only translate colour values of the subject into tones of lighter or darker grey.
Mostly these correspond fairly closely to the brightness to the brightness of the colours, but do not, of course, differentiate
between them. In certain cases the difference between the brightness of two colours may be so slight that both record in
almost the same tone of grey.
There a filter helps by modifying the depth of one or the other colour, and so making it show up lighter or darker than it
would normally.
The commonest example is the blue sky in a landscape, with white clouds. The blue is so brilliant (and the film is often
excessively sensitive to it) that the clouds do not show up against it. By putting a yellow filter in front of the camera lens
we can subdue or "hold back" the blue, so making it record darker in the final print. We can even go further and over-
emphasize the effect progressively with an orange or red filter; these darken the blue so much that the .sky looks almost
black for a really dramatic effect.
The same considerations hold for other filter effects. For instance, the film renders a red rose in the same tone of grey as
the green leaves of the rose bush. With the colour contrast gone, the rose disappears in its surroundings. A green filter
makes the rose darker and the leaves lighter; conversely, a red filter will show up the rose as light against dark foliage.
Scientifically, both filters falsify the tone rendering, but produce a more acceptable pictorial result.
In all these cases a filter lightens objects of its own colour and darkens objects of its complementary colour. Apart from
isolated Instances in pictorial photography, such contrast control is very valuable in copying and scientific work (e.g.,
photomicrography).
All filters cut out some part of the light and thus, as a compensation, an increase exposure time is necessary when using
them. This is stated on most filters in the form of a filter factor indicating by how much (e.g., 2 times, 3 times) the
exposure must be increased with that filter. The factors are approximate for they depend not only on the nature of the filter
but also on the exact colour sensitivity of the film and on the colour of the prevailing light.
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