Yashica Twin Lens Reflex Guide - Focal Press January 1964
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Colour Reversal Film
This produces a colour transparency on the actual film exposed in the camera. This transparency held up to the light shows
a positive image with all parts or the subject in their original colours. It can be viewed in a suitable transparency viewer
with a magnifier or it can be projected in a slide projector to give a large and brilliant picture on a screen.
There is little doubt that the projected image is the most natural and best for showing colour.
Although the colour transparency is an end product, it can still be used to make:
•
duplicate positive colour transparencies,
•
a black-and-white negative which can then be used to produce black-and-white prints or enlargements,
•
a colour negative for making colour prints and enlargements, as from colour negative film (described below),
•
direct colour enlargements on colour reversal paper. Colour prints on paper invariably show a loss of colour
quality as compared with the original positive transparency. For correct colour rendering, colour reversal films
have to be carefully matched to the light by which they are to be exposed.
Accordingly, some makes are available in two or more of the following types:
•
daylight colour film (type D or T) which will give correct colour reproduction in daylight or with blue-tinted
flash bulbs or electronic flash.
•
artificial light type colour film which will give correct rendering by photoflood illumination (type A or K), or
high-power tungsten light,
•
flash type colour film (type f) which will give correct rendering with the normal clear flash bulbs.
Colour films made for one kind of light may often be used under different light conditions with the aid of a conversion
filter as recommended by the manufacturer.
Different makes of colour film may yield transparencies of a slightly different characteristic colour quality, colour
saturation and colour contrast. Which you prefer is very much a matter of personal taste, and you can only be
recommended to try various makes to find the one which suits you best.
Colour Negative Film
On processing, this produces a colour negative which shows a negative image of the subject in its complementary colours
- e.g., blue appears yellow, red appears blue-green and so on. These colours may sometimes be hidden Linder an overall
orange or reddish tint.
The main purpose of the colour negative is the production of colour prints on paper. The quality is generally higher than
that of prints obtained from a positive transparency.
From the colour negative you can make:
•
any number of Colour prints in varying sizes,
•
direct black-and-white prints or enlargements, in the same way as from a black-and-white negative,
•
positive colour transparencies for viewing or projection. Most colour negative films are suitable for exposure by
any type of light - e.g., daylight, flash or photofloods. The necessary adjustment of the colour rendering is carried
out during the printing stage. Manufacturers sometimes recommended conversion filters even with colour
negative films. These mainly serve to simplify the subsequent correction needed in printing.
Colour Film Speeds
The majority of colour films, reversal and negative, are rated between 25 and 64 ASA or 15 and 19 DIN, corresponding to
a slow to medium speed for black-and-white material. A few films go up to 160 ASA or more for poor light conditions.
Others may be as slow as 10 ASA or 11 DIN.
As with black-and-white films, the slower types tend to yield improved image detail, especially with negative colour film,
while the fastest emulsions may show slightly reduced colour saturation and image sharpness.
