Synthacolor (British Synthacol Ltd; Rowsley Works, Reddish, Stockport) were probably the first organisation within the UK to announce a home developing and printing outfit for colour negative film. The date was September 1953 (ref: Photography magazine, September 1953).

Because of their earlier entry into home colour film developing and printing, the BJPA contains various Reviews, starting in 1954.

The film processing kit comprises four solutions, supplied as powder chemicals packed in five tins, each making 1 litre of solution each with the exception of the intermediate stop bath which makes 2 litres. The four solutions are the colour developer, an intermediate bath, a bleach bath, and a final fixing bath. It will be seen that a combined bleach-fix, such as is commonly used for the processing of colour negative materials, is not supplied (but see the BJPA 1956 test of the new Synthacolor kit, below).

All the chemicals dissolve readily and the solutions may be made up quickly; the colour developer however, as is usual with such solutions for colour negative materials, must be allowed to stand for twelve hours before use.

Comparative tests were made on the three makes of colour negative available to determine the colour balance and gradation given by the Synthacolor negative processing kit and the official processing chemicals or service offered by the manufacturer. In each case the Synthacolor kit gave extremely similar results to those given by the official processing both as regards colour balance and the gradation of the negatives. For the Pakolor negatives a somewhat different filter pack would be needed for the two differently processed films but this change would not be greater than the normal amount of filter correction needed.

Thus the Synthacolor colour negative processing kits are a most useful product and provide the photographer with an alternative source of processing solutions at reasonable cost. All the components of the kit may be obtained separately, a useful point since it is not advisable to use the colour developer and intermediate stop bath more than once, whereas the bleach and the fixer will handle a fair quantity of film before exhaustion."

"Synthacolor paper is a colour positive material of the conventional type for the making of prints from colour negatives either by contact or by enlargement.

The printing kit comprises a supply of the paper in 3½"x 2½" size, 36 gelatine colour correction filters, and a glass filter which gives a basic modification of the colour temperature of the light source. The colour correction filters consist of 3 sets of twelve filters, yellow, cyan and magenta in density steps of 0.05 from 0.05 to 0.60. Since the paper, like any colour printing paper, is panchromatic, it has to be handled in the light of a green safelight of low brightness, though the amount of light which it passes is appreciably greater than a normal panchromatic safelight screen. the darkroom. All the chemicals except the stop bath are supplied as powders which make 1 litre of solution.

After the first fixer the green safelight may be changed for a much brighter orange or yellow-green but the print cannot be viewed in white light until after the final fixing bath. The complete processing routine takes some 59min. and a test print can be assessed for colour balance after some 39min.

The recommended light source for the enlarger or printing box is a standard high intensity enlarging bulb and the basic correction filter, called an R filter, has to be inserted into the light path.

Since the colour paper has similar speed to a normal black-and-white bromide paper it is recommended that a black-and-white print be first made from the colour negative and after development this can be assessed for exposure. This same exposure time is then used for a no-filter print on the colour paper test strip (test strips are included in the packets of paper).

Prints of similar quality to those made on any other colour paper can be made on the Synthacolor material and it would seem to be possible to print from any of the three types of colour negative films currently available using correction filters within the normal range. As with all materials of this type care in processing is needed if the whites of the print are not to be degraded with a colour stain.

The paper is available in both 10 and 25 sheet packets in 3½"x 2½" and 6½"x 4½" sizes only. All sizes and packings are on a double-weight base. The green safelight, Synthacolor No.1, is available in 7 X 5, 10 X 8, and 12 X 10in sizes and replacement chemicals for all the baths in the processing kit may be obtained."

Compared to the 1954 Synthacolor kits reviewed above, in 1956 Synthacolor are claiming that their home colour kit has:

• reduced number of chemicals (3 including Bleach-Fix instead of 5),
• dual purpose suitability for developing colour negative film as well as colour printing paper,
• only 25mins. before the print can be examined (albeit by artificial light) compared to the previous 39mins.

The BJPA reported:
"This new processing kit is designed to process the colour negative films and papers that are generally available.

The kit offers a considerably simplified processing schedule for both films and papers since it now incorporates a combined bleach-fix solution; in addition the developer is so formulated that it is made up as three stock solutions which are mixed in differing proportions for films and paper.

The developer pack contains sufficient to make 84 fluid oz. of the necessary stock solutions, the stop bath enough to make 35 fluid oz. of stock solution (which dilutes to make 10½pints = 210 fluid oz of working solution), and the bleach-fix makes 70 fluid oz. of working solution.
Price of the outfit is £1. 13s, and the individual components are available separately at l0s. 6d. for the developer, 2s. 6d. for the stop bath, and 19s. for the bleach-fix."