Submitted by Al …
(Adapted from The Encyclopedia of Photography ©1963)
In the second of our five part series, we looked at the development of Ektachrome and Kodacolor films, and Type C and R Papers. Part three will explore the general use of film, artificial light, filters, and colour negative films.
USE OF FILM
As evidenced in the preceding history of Kodak colour films, improvements in products are constantly being made, with the result that any published recommendations must be changed from time to time. Any changes for a film will be only those which will be reflected in improved colour rendition, increased sharpness, or easier handling. However, the instruction sheets which are packed with the film in use should always be considered as the primary source of information.
Kodak colour films are available as roll films and in 35mm and sheet form. Kodak colour movie films are available in magazines and spools for 8mm and 16mm motion-picture cameras. The 16mm colour film is also available in magazines and on spools perforated on two edges for silent motion pictures and on spools only, perforated on one edge, for sound motion pictures. Ektacolor and Ektachrome films are also available in long rolls up to 70mm wide, with and without perforations for various specialized applications.
All colour films are available for daylight use. Type F films are for clear, medium delay flashlamps. Type B films are for use with 3200 K lamps. Type S films are short exposure films for use with daylight, electronic flash, or blue flash. Type L films are for long exposure.
Films designated as professional films are designed specifically for professional use under controlled conditions of storage and handling, and will enable the photographer to obtain reproducible results when used under those conditions. Professional use presupposes refrigerated storage, immediate use, and immediate processing when removed from storage. Amateur type films are designed to furnish the best possible results though stored for considerable periods of time on the dealers’ shelves at normal room temperatures, and when retained over short periods of time in the user’s camera before removal and processing.
USE WITH ARTIFICIAL LIGHT
Where colour temperatures are given, the figures should be used with caution. These numbers designate only the colour of the source and not the spectral-energy distribution or its photographic effect. It is not sufficient for a filter to provide merely a change in colour temperature. For use with a Type B colour film for example, the filter must also convert the spectral-energy distribution of the source to very nearly the distribution of a tungsten lamp actually operated at 3200° K.
Colour temperature values for various daylight conditions tend to be misleading when the attempt is made to apply them to colour photography. Since two-point colour temperature meters read only the ratio between red and blue light and do not adequately measure spectral-energy distribution, their use should be confined to tungsten sources or sources having this type of energy distribution. A three-point meter is better for outdoor use.
While colour temperature readings can be taken from a tungsten lamp, the photographic effect of fluorescent lighting cannot be estimated from a colour temperature meter reading, although visually the colour of light from a deluxe warm-light fluorescent lamp will look much the same as that from a 500-watt tungsten lamp.
USE OF FILTERS
In general, any colour film will work best with the type of lighting for which it is designed, although adaptations to other light sources can be made with filters. Exact filtering for florescent lighting is extremely difficult, if not impossible. The severe deficiency in red output of fluorescent lamps means that the filtering action must usually be heavily red. Such dense red filters may increase exposure times so much that the emulsion layers of the film no longer retain their normal speed ratios. Further compensatory filtering or exposure time may be necessary.
Other factors add to the problem of finding suitable filters for use with fluorescent illumination. Fluorescent lamps vary widely in colour and brightness:
among different brands
from lamp to lamp within the same brand
with voltage fluctuations
with the temperature under which the lamps operate
with age, and
during a single AC cycle
Problems with this latter phenomenon can be avoided by using a shutter speed longer than 1/60th second. Where extensive filtering is used and the exposure becomes excessively long, Kodak Ektacolor Film, Type L, should be used.
In colour photography, consideration must be given to the lens. A lens must be highly corrected for colour photography, especially if the results are to be considerably enlarged. Unless the lens is corrected for lateral colour, this aberration may cause colour fringing, and stopping down the lens will not reduce its effect. The lens should also minimize longitudinal chromatic aberration which causes the position of the image itself to change slightly with the colour of the wavelength.
COLOUR NEGATIVE FILMS
Kodacolor Film is a dual-purpose colour negative film supplied in standard roll and 35mm film sizes and designed for exposure in daylight or with clear flashbulbs. Kodacolor prints and enlargements are made from the negatives, or they may be printed on Kodak Ektacolor Professional Paper or Kodak Ektacolor Paper. Transparencies can be made on Kodak Ektacolor Print Film or Kodak Ektacolor Slide Film. As a colour negative film it affords the photographer a choice of colour print, colour transparency, or black-and-white print. Black-and-white prints are made on a panchromatic paper. Because the film may be used outdoors by sunlight or indoors with clear flash, it is used with two radically different types of lighting. The negatives obtained with each light source are readily distinguishable to the printer, and compensation is easily made during the printing. Light sources should not be mixed.
Blue flashbulbs should not be used indoors unless it is to supplement daylight. When flash is used outdoors for fill-in, blue flashbulbs should be used. Most modern photofinishing equipment is adapted to provide this type of compensation. For those who wish to process their own film and make their own colour prints, all negatives can be brought to approximately the same balance by means of a filter over the camera lens during exposure. This will avoid the large changes in the filter pack used later during colour printing.
One way of working is to expose without a filter when clear flashbulbs are used indoors. Negatives exposed by daylight or electronic flash and intended for user-printing can then be brought close to the same balance by the use of a Kodak Wratten Filter No. 85C for daylight, or No. 85 for electronic flash. When the No.85C filter is used, a daylight exposure index of ASA 25, or speed value 3°, should be used. When using lamps, enough light must be provided for exposure of ½ second or shorter to avoid reciprocity failure. See Table 1.
Kodacolor films will be processed by independent photofinishers of by Kodak. With the Kodak Color Processing Kit, Process C-22, the film may be easily processed by the photographer.
Kodacolor roll film is available in these sizes: 116, 120, 127, 616, 620, 828, and 35mm.
Kodak Ektacolor Professional Roll Film, Type S, has a speed of ASA 80. It is balanced for daylight, electronic flash, and blue flashbulbs. It is tested for colour balance with electronic flash at 1/1000th second without reciprocity failure. When the use of photoflood illumination becomes necessary, it may be used with an 80B filter and a prolonged exposure up to 1/10th second with reasonable certainty of good results. This film is available in 120 rolls and in standard sheet film sizes.
Processed Ektacolor Professional Roll Film, Type S, can be differentiated from Kodacolor Film, 120, by the edge markings which are green rather than blackish as on Kodacolor Film. Ektacolor Professional Roll Film negatives will require about CP30Y or CC30Y more in the filter pack when printing than Kodacolor negatives. Ektacolor Professional Roll Film, Type S, may be processed in the same Process C-22 solution as other Ektacolor and Kodacolor films.
Kodak Ektacolor Film, Type L (Long Exposure), is also a professional sheet film designed for making colour negatives at exposure times of 1/5th second to 60 seconds with 3200 K lamps, or with the appropriate filter, by photoflood or daylight illumination.
Coloured couplers in the film provide automatic colour correction and make quality in colour reproductions without supplementary masking. The negatives can be printed or be used for making transparencies or black-and-white prints as with other Ektacolor or Kodacolor films. The speed of Kodak Ektacolor Film, Type L, when used with 3200 K lamps is ASA 16, a speed value of 2° (for a five-second exposure). This film should not be exposed for times shorter than 1/5thsecond or longer than 60 seconds. Other exposure values are shown in Table 2 below.
The meter calculator should be tentatively set for a speed of 16, which applies to a five-second exposure. Calculate a tentative exposure time for the desired lens opening. If this time is much shorter or much longer than five seconds, select from the table the effective speed which applies. Use this value to determine the correct exposure time at the desired lens opening. Kodak Ektacolor Film, Type L, may be processed in Process C-22 solutions. It is only available in cut sheet film in sizes from 2-1/4” x 3-1/4” to 11” x 14”.
Kodak Ektacolor Print Film is supplied in sheets from 2-1/4” x 3-1/4” to 20” x 24”. It is multilayer colour material designed for direct printing or enlarging from Kodacolor negatives and Ektacolor internegatives. It can be exposed with ordinary contact printing or enlarging equipment and processed with ordinary darkroom equipment. It yields brilliant positive transparencies for use in displays or for photomechanical reproduction. The exposure time of the film varies, depending upon factors such as subject matter and negative density. A typical Kodacolor negative or Ektacolor internegative requires ten to twenty seconds exposure when the illumination is two foot-candles measured at the printing surface and without the negative or any colour compensating filters in the light beam. Filters may be used to correct the colour balance.
Kodak Ektacolor Print Film is not processed by Eastman Kodak Company, but may be processed in Process C-22. Splicing tape and Kodak Ektacolor Print Film Cement can be used to join two or more sheets of the processed film together.
Kodak Ektacolor Slide Film is a similar material, supplied only in 35mm rolls, 100 feet long, and is used for making 35mm transparencies from 35mm colour negatives, or reductions from larger negatives to the 35mm size.
Kodak Ektacolor Internegative Film: Although colour prints from colour transparencies can be made directly on Kodak Ektachrome Paper, prints on Kodak Ektacolor Paper may be desired. In this case it is necessary to first make an internegative. Kodak Ektacolor Internegative Film is designed for this purpose.
All of the foregoing films are colour negative films. They can be used to produce transparencies, colour prints, or black-and-white prints. In this way they are the key to a very versatile system of photography. For many photographers the colour negative system has replaced both colour transparency photography and black-and-white photography. Colour prints from contact size to gigantic murals are possible. The colour negative can be used again and again to make any desired type of reproduction in any quantity.
One colour negative in the enlarger can produce many results. The print can be made lighter or darker, and it can be enlarged, reduced, or cropped. Overall colour balance can be altered subtly or dramatically by changes in the printing filter pack, or specific areas of the picture can be changed in density, colour-balance, or both. Dodging and printing-in techniques are the same as in black-and-white printing with an added feature: colour filters can be used as tools to affect both colour and balance.
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