Kodachrome films have a dynamic range of around 12 stops, or 3. The color rendering of Kodachrome films was unique in color photography for several decades after its introduction in the s.
Even after the introduction of other successful professional color films, such as Fuji Velvia, some professionals continued to prefer Kodachrome, and maintain that it still has certain advantages over digital. Steve McCurry told Vanity Fair magazine:. It had a great color palette. Velvia made everything so saturated and wildly over-the-top, too electric. Kodachrome had more poetry in it, a softness, an elegance. With digital photography, you gain many benefits [but] you have to put in post-production.
This is because developed Kodachrome does not retain unused color couplers. Unprocessed Kodachrome film may survive long periods between exposure and processing.
In one case, several rolls were exposed and then lost in a Canadian forest. Upon discovery 19 years later they were processed and the slides were usable.
A 35mm Kodachrome transparency contains an equivalent of approximately megapixels of data in the 24 mm x 36 mm image.
Some software producers deliver special Kodachrome color profiles with their software to avoid this. An IT8 calibration with a special Kodachrome calibration target is necessary for accurate color reproduction.
Many scanners use an additional infrared channel to detect defects, as the long wave infrared radiation passes through the film but not through dust particles. Kodachrome interacts with this infrared channel in two ways.
The absorption of the cyan dye extends into the near infrared region, making this layer opaque to infrared radiation. Kodachrome also has a pronounced relief image that can affect the infrared channel. These effects can sometimes cause a slight loss of sharpness in the scanned image when Digital ICE or a similar infrared channel dust removal function is used. Kodachrome, and other non-substantive films, required complex processing that could not practicably be carried out by amateurs.
The process underwent four significant alterations since its inception. The final version of the process, designated K, was introduced in The process was complex and exacting, requiring technicians with extensive chemistry training and large, complex machinery. The first step in the process was the removal of the antihalation backing with an alkaline solution and wash. The film was then developed using a developer containing phenidone and hydroquinone, which formed three superimposed negative images, one for each primary color.
After the first developer was washed out, the film underwent re-exposure and redevelopment. Re-exposure fogged the silver halides that were not developed in the first developer. The red-sensitive layer was re-exposed through the base of the film with red light, then redeveloped forming cyan dye. The blue-sensitive layer was re-exposed through the emulsion side of the film with blue light, then redeveloped forming yellow dye.
The green-sensitive layer was redeveloped with a developer that chemically fogged it and formed magenta dye. After color development, the metallic silver was converted to silver halide using a bleach solution. The film was then fixed, making these silver halides soluble and leaving only the final dye image. The final steps were to wash the film and mount the film in slide frames.
Due to its complex processing requirements, Kodachrome film was initially sold at a price which included processing by Kodak.
An envelope was included with the film in which the photographer would send the exposed film to the nearest of several designated Kodak laboratories. After , as a result of the case United States v. Eastman Kodak Co. Kodak entered into a consent decree that ended this practice in the United States, and allowed independent processing laboratories to acquire the chemicals needed to process Kodachrome films. Kodak announced that the remaining film, Kodachrome 64, would no longer be manufactured.
Because of the decline in business, many Kodak-owned and independent Kodachrome processing facilities were closed. The loss of processing availability further accelerated the decline in Kodachrome sales. In , Kodak attempted to increase the availability of K processing through its K-Lab program. This effort did not endure and all the K-labs were closed by Without that product, we would not have the pictures.
Pictures that were taken on other films have suffered more than Kodachrome. Kodachrome was thought to last 50 years, and it has.
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One of their early processes, patented in , was for a two-colour method using a plate coated with two emulsion layers. The upper one was a slow emulsion, sensitised to blue and green light, while the bottom layer was a faster red-sensitive emulsion. The top layer was dyed yellow to prevent blue light from reaching the bottom layer. The speeds of the two layers were adjusted so that both were correctly exposed by a single exposure. They suggested several ways of developing a colour image, the most significant of which involved the use of a developer which would act on the upper layer only, not penetrating to the bottom layer before development was complete in the layer above.
This allowed the silver image in the upper layer to be bleached and toned blue-green, and then the bottom layer could be developed and dye-toned orange-red. Alternatively, both layers could be developed together, and the images bleached, and a controlled penetration toning solution applied so as to tone only the upper layer, the bottom layer being subsequently dye-toned as before.
Although as it stood this process was not very practical, it was to evolve into an important commercial process. In Mannes and Godowsky had been introduced to Dr C. Through his good offices, the Kodak Research Laboratory coated many experimental plates for the two amateur researchers. They discovered that a major problem with multilayer emulsions was that the dyes used to sensitise them for various colours would wander through the layers, making the red-sensitive layer slightly green-sensitive, and vice versa.
In the Kodak Research Laboratory discovered a new range of sensitising dyes, some of them much less mobile than their predecessors. In Mannes and Godowsky were invited to join the staff of the Kodak Research Laboratory, where they concentrated on methods of processing multilayer films, while their colleagues worked out ways of manufacturing them.
The result was the new Kodachrome film, launched in Three very thin emulsion layers were coated on film base, the emulsions being sensitised with non-wandering dyes to red, green and blue light, the red-sensitive layer being at the bottom. To deal with the unwanted blue sensitivity of the red and green layers, a yellow filter layer was provided below the top coating and above the bottom two.
A single exposure produced a record of the red, green and blue content of the scene in the three layers. The exposed film was first developed to give a negative silver image in the three layers, the silver then being chemically bleached out, together with the yellow filter layer, which was a form of very finely divided silver.
The film was then re-exposed to light, and all the remaining silver salts were developed in a solution containing the colourforming couplers to produce positive cyan dye images in all three layers. Next, a bleaching solution, the penetration of which could be accurately controlled, was applied to the film until the cyan dye in the top two layers was removed, but leaving that in the bottom layer intact.
The bleaching solution also converted the silver image in the top two layers back into developable silver bromide. A second colour development followed, using a magenta coupler, to produce a magenta dye image in the top two layers. Another bleaching stage removed the magenta dye from the top layer, which was then redeveloped in a yellow dyeforming developer. Now, the film had positive images in both silver and dye in each layer. The silver was removed by bleaching, leaving three clear dye images only.
The new process was released first in the form of 16 mm movie film, announced in April Because of the very complex processing involved, the Kodachrome films had to be returned to the manufacturer for processing, and the film was sold with the cost of development included.
It sold for 12s 6d for an eighteenexposure film, including the cost of processing, which compared not unfavourably with the cost of a black and white film together with developing and printing charges. At first the films were returned in an uncut strip, for the customer to mount as slides, or to project in a film strip projector. In February a ready-mounting service was announced and the transparencies were returned to the customer in 2 x 2 inch 5 x 5 cm card mounts.
The Kodachrome film was the first commercial integral tripack film, and with its great transparency favourably contrasted with the rather dense additive screen plates and films.
However, the processing cycle was very complex, and the stability of the dyes was not very good. Both problems were resolved with the introduction of an improved process in The film, of the same construction as before, was first developed to a black and white negative. Then, the film was re-exposed through the back to a red light, which affected only the bottom layer, which was then developed in a cyan dye-forming developer. Then the film was re-exposed from the top to blue light, and the top layer was developed in a yellow dye-forming developer.
Finally, a magenta dyeforming developer, containing a chemical fogging agent, was used to develop the middle layer. Now, the film had both negative and positive images in silver in each layer, and positive dye images.
It remained only to bleach out the silver images, and the yellow filter layer, and a colour transparency of dye images only was left. The basis of the Kodachrome film process has remained unchanged ever since. The improved process was still complex enough that the processing of the film could only be carried out by the manufacturer, or by a laboratory equipped with the necessary complex machinery.
Kodachrome Professional film remained on the market until , when it was superseded by Kodak Ektachrome film, introduced in , which could be processed by the professional user. Coe, Brian : Colour Photography. The First Hundred Years Surface emulsion side, raking light. Film: Regular 8mm home movie, anonymous The project began even before the two young men graduated from high school. After viewing the film Our Navy in the early two-color additive color system , Prizma Color, Mannes and his friend Godowsky began experimenting with the use of colored filters and film, patenting a new process even before their high school graduation.
They continued their experimentation and research while Mannes was studying physics and piano at Harvard and Godowsky was studying violin at UCLA. Eventually, with backing from an investor, the pair was able to convince Kodak of the value of their discoveries.
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