TECHNOLOGY, EVOLUTION AND REMARKABLE FEATURES
The fabulous Kodachrome slides were invented in 1936 by two musicians very expert on photography and chemistry called Mannes and Godowsky, with the aim of helping Eastman Kodak in the sales of its 16 mm cinematographic amateur film.
It was the first 35 mm photographic emulsion in the world, together with the German Agfacolor Neu, appeared in an almost simultaneous way.
It must be highlighted the spectacular evolution of Kodachrome films, regarding nominal sensitiveness and its manufacturing process, because for instance during fifties it was a 12 DIN/12 ASA film, this being a period in which the ISO 100 emulsions were deemed very quick.
Historically, Kodachrome changed from the starting K-1 process to the K-12, and it would become worldly consolidated at a worldwide level with the current K-14, its actual cornerstone.
As a matter of fact, Kodachrome films use a unique technology, since they don´t include any colour couplers (as happens in all the slides featuring E-6 process), it being incorporated through the processing chemical components in a proportional way to the exposure received by its different layers of black and white emulsion sensitised for each one of the primary colours. The silver halide image is substituted by crystalline colorants, chemically more resistant than the amorphous ones used in the structure of the emulsions based on chromogenic chemistry.
This very complex technology, requiring the use of very bulky and expensive machinery, has been the alma mater of Kodachrome legend: ultrafine grain, huge resolution ability, superlative acutance and an unbeatable stability before and after the process, with very peculiar palette of colours and tonalities, certainly loved and almost idolized during more than fifty years by the best photographers in the world till currently, and it has been the only chemical emulsion performing as main character of a song (´Kodachrome´, created by Paul Simon in 1972).
It´s incredible that for more than half a century until the nineties decade (which brought about the arrival of Fujichrome Velvia, Kodak Ektachrome 100VS and Fujichrome Provia 100), Kodachrome displayed an indisputable dominance as regards acutance and colour saturation, compared to the rest of slides, and besides it was proved that in some elite graphic magazines, after the photomechanics and in sizes not exceeding 20 x 28 cm, the images transferred to paper from an original Kodachrome 35 mm slide showed a global aesthetic beauty of image superior to those ones obtained from original medium format 6 x 6 cm slides from other brands!
And a myriad of photographers who worked in tropical areas with adverse climatology for the emulsions, verified that Kodachrome slides had wonderful stability properties under such conditions, clearly beating the rest of slides in this respect.
It´s impressive the fact that Kodachrome slides have been extraordinarily well preserved and have kept their brilliant colours almost flawless since the autumn of 1938.
According to tests made by Henry Wilhelm in France in 1988, at 24º C and at 40º C of relative humidity, Kodachrome slides are able to endure 90 years intact until a density loss of 10% appears.
Therefore, it´s decisive the fact that the final Kodachrome image is constituted by molecules of pure dye, introduced during the process and not present in the silver halide emulsion during the exposure time.
And here lies the pith of the question, for Kodachromes are essentially black and white films featuring three layers sensitized for the three basical colours, and during the K-14 and after a specific development for each of the three quoted layers, the colour is added by means of the ´dyeing´ of each one.
It all is awesome, on being reported that compared to the three quoted layers of Kodachrome, Fuji Velvia has 17!
Four have been the Kodachrome flagships: