Die Anmerkungen und Quellenangaben zum Buch
The writer is unaware of whether or not it is the practice to correct the colour balance of a motion picture print by a subsequent bath intended to reduce one of the three subtractive primaries. If the excess is red, green or blue, then baths must be successively used of yellow and magenta reducers, cyan and yellow, or magenta and cyan. Apparently two filters are occasionally employed for a brief period should operation demand it.
For direct illumination Agfa No. The latter position was selected for the maximum transmission of the safelight filter, owing to high sensitivity of the retina in this region, and resolving power is also higher than for red or green light. It is better to have high visual acuity in the darkroom than high illumination. While filters can be made which transmit light of a narrow wavelength band in the yellow region they are not efficient.
These safelights must be mechanically air-cooled. Using two filters of 20 x 30 cm. The safety margin for Agfacolor positive is 30 minutes. The German technicians do not seem to have used a special illuminant in printing machines. A system of combination of light sources such as has been successfully used for the printing of Dufaycolor would seem to present valuable advantages. This consists in the mixture of light given by: A.
The combined radiation consists of:. This lamp has now been standardized and its relative output of radiation should be constant after the lamp has been run continuously for 75 hours. During this ageing period it is quite possible that the line spectral emission ratio varies to a minor extent, but no data is available. It is proposed by Dufay-Chromex Ltd. On theoretical grounds there are good reasons to expect a marked improvement over the previously employed system. Published by the U. Agfacolor Sensitizers and Colour Couplers. Chemical Formulae. We give below the formulae of the principal sensitizers and colour couplers used for Agfacolor negative and positive films:—.
Paul Keck, formerly of Zeiss. This is a very interesting report upon some colorimetric work carried out in Germany on reproduction deviations found in the reproduction of colours by the Agfacolor films.
After a review of modern colorimetrical methods, he sums up the mathematical formulation of the problem of colour photography by A. Hardy, F. Wurzburg and others, in this next statement. Schultze and H. Hoermann of Agfa, Wolfen. Keck quotes from an unpublished paper by these authors. They calculated the reproduction of three different sets of samples:. The Oswald eight full colours. Eight saturated pigment samples from the Baumann-Prase Atlas. Eight spectrum wavebands of constant luminance. Generally the tristimulus values give the worst results.
Here the RUCS distance was only , and for the pigments Sensitivities with large overlapping spectral curves give poor reproduction. This is especially true for the tristimulus values of the spectrum used as sensitivities. Sensitivity curves calculated according to Hardy and Wurzburg give very good results if the negative parts, as well as the overlapping sections, are neglected. The reproduction is almost as good as before when optimum colours are used which do not cover the whole visible wavelength range. The best colour reproductions result in average deviations from in the RUCS system.
Red and magenta chromaticities in general give rise to the largest differences and yellow hues correspond to the smallest ones. The same authors have published measurements on colour reproduction by Agfacolor reversal film of a set of 12 highly saturated filters. The niters were also reproduced on Agfacolor Reversal Tungsten Type. Dominant wavelength and colorimetric purity of the originals and reproductions were measured. The colorimetric purity values were transformed into excitation purity. For the 12 selected samples the dominant wavelengths and excitation purities are given in the accompanying Table The values under Dl and D2 refer to two exposures in daylight and A refers to the exposure to tungsten light.
The distortions are serious, especially with blue and violet hues. As far as luminance is concerned the transparency of the reproduction is always less than that of the original filter. The same authors measured the reproduction chromaticities of the same 12 filters as reproduced by the Agfacolor negative-positive process and also obtained comparison reproductions by printing Agfacolor positive with three separation negatives exposed through Agfa tricolor filters 40, 41 and The light source was ICI—A.
Narrow-cut tricolor filters were used for printing. The reproduction of blue and violet filters i, k and l, display larger deviation than did the reversal film. The print made from the separation negatives was little better.
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Eight pigments of high saturation in the Baumann-Prase Color Atlas were reproduced by the reversal and by the negative-positive process. Results are given in the following Table. Note the dominant wavelength of No. The reproduction of No. On the other hand No. In general, the Agfacolor process gave deviations about twice as great as by the best an additive system could yield.
Reversal was slightly superior to negative-positive. This is an interesting question and there is not much data yet to help us to come to reliable conclusions. Masking is a pastime for mathematicians. The writer is firmly convinced that up to the present, a set of separation negatives represents by far the most reliable and accurate foundation.
Beam-splitter cameras are expensive, cumbersome, and delicate, but they give the technician an odd feeling of security after experience of the vagaries of monopack. Nevertheless negative-positive processes, such as Agfacolor, have their proper field of application and we must hope that one of the manufacturers will shortly revive its production. In the meantime physicists are welcome to cover pages with their symbols to prove that something can be done on paper which cannot be done in the laboratory. Brock, who visited the Agfa film factory in June , stated in the report C.
Trip No. Final Report No. London, H. Stationery Office. Report No. Farben, Agfa Subsidiary Wolfen. Ranger and others, Jan. Final Reports Nos. Rose and Br.
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White T. Note: B. Cornwell-Clyne, Adrian : Colour Cinematography. This criticism based on the fact that Ryan did not mention Agfacolor.
Einfach Managen Komplexität Vermeiden by Dieter Brandes
Only the American author James L. Limbacher gave some information on Agfacolor and listed many titles of feature films in his book Four Aspects of the Film New York Actually the history of Agfacolor is fairly unknown in the U.
Agfacolor was introduced by the German Agfa company in — now 60 years ago. Before that Agfa had started manufacturing a photographic color reversal film Agfacolor-Neu in November , only three months after the introduction of the first Kodachrome slide film in the U. During the second world war the Third Reich used the Agfacolor stock for 13 full-length completed color features. Principally Eastman Color is based on the same idea of multilayer color film but uses different color couplers for the dye generation.
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The article of Gert Koshofer, former employee of Agfa-Gevaert and past Secretary General of the German Photographic Society, covers both the technical and the contemporary history of the German invention Agfacolor. The motion picture industry used it under the different political conditions of national socialism, East-bound communism in East Germany and West-bound democracy in West Germany.
Its first use for a feature film production was for the UFA movie Frauen sind doch bessere Diplomaten i. After a lot of problems with the new film medium, especially with different color temparatures during the day on location, this film was first shown in Berlin on 31st October It was a big success in the public, but suffered from some deficiencies as critisized by experts. Before that time there had been no full-length color feature in Germany. As forerunners of Agfacolor served here two-color systems like Ufacolor Agfa Bipack System , the three-color printing process of Gasparcolor and the complicated Agfa Pantachrom system.
These color processes were only used for short subjects like documentaries and advertising films — the German producers were too angry to make their color films with such inadequate and awkward systems, which required special equipment like bipack cameras. The Beauty Spot.
But Agfacolor conquered them all by its relatively simple method using normal movie cameras, a printing process similar to black and white films and common cinema projectors. This was a real sensation compared with Technicolor, which at that time required the special beam-splitter camera and the lavish imbition dye transfer printing process. The development and introduction of Agfacolor had been driven forward by the German government, especially by the nazi propaganda minister Josef Goebbels who was very interested that the German film production could soon compete with Hollywood in the field of color cinematography.
The Golden City to be made in Agfacolor.
In dose cooperation with his director of photography Bruno Mondi Harlan perfected the technique and style of German color movies during war time. This work culminated in the propaganda feature Kolberg with great historical battle scenes, carried out by , Wehrmacht soldiers and 4, mariners. But the other Agfacolor features of the Third Reich were harmless dramas and musical entertainment subjects.