Kodachrome is a registered brand name of the Kodak company for a slide film produced from 1935 to 2009. The film, which came as Kodachrome 25, Kodachrome 64 and Kodachrome 200 (The numbers stand for the ISO sensitivity of the film), is generally characterized by its very high sharpness, extremely natural colour reproduction and high colour stability.
It is precisely this characteristic of colour fidelity and colour stability that we notice again and again in our scanning service: While we very often with 30-year-old “normal” slides need to apply colour restoration methods, with 30-year-old Kodachrome slides you get images as if they were taken only yesterday. Yet 30 years is nothing for Kodachrome film, which is supposed to maintain its colours for up to 60 years.
However, Kodachrome films must also be treated differently from other colour films, since they are different.
A kind of black and white film
In fact, Kodachrome is not a normal colour film, but has three B/W layers that later become red, green and blue. The colours are created during the development process, not during the exposure. This is why Kodachrome film could not be developed in the photo lab around the corner (normal E-6 process), but had to be sent to Kodak. There was a special K-14 process for developing Kodachrome films. The development of Kodachrome slides was discontinued in 2010. To our knowledge, there is no one left who can develop these films!
What were the advantages of this special development process? The colours of Kodachrome pictures were the same for all Kodachrome films, i.e. a green meadow photographed with a Kodachrome 25 has the same colour as one taken with a Kodachrome 64-film. In this K14 development process, the film was immersed in more than 30 baths, each for a fixed time. In each bath, dye diffused very slowly into the film. Very stable dyes were used in this process, so that the long colour fidelity could be guaranteed.
Since Kodachrome slides are particularly fine-grained, they have a very high resolution and a very large density range. If you do not want to accept any losses during digitization, you need a high-resolution scanner with a large density range. The NIKON Super Coolscan 9000 ED, used by Digitized Memories, is such a scanner
How do you recognize Kodachrome films?
In Australia, Kodachrome slides usually have a thin cardboard frame on which “Kodachrome” is written very thickly. This is how you got the slides back framed when you sent them directly to Kodak’s laboratory. But there are also unframed Kodachromes, so the framing was left to the photographer.
A Kodachrome slide can usually be recognized by the inscription on the bottom of the film: There you will find abbreviations such as KM (Kodachrome 25), KR (Kodachrome 64) or KL (Kodachrome 200), possibly with a preceding P (professional version).
But even without these codes, Kodachromes can be recognized. Any slide always has a glossy and a matt layer side. If you look at the slide from the glossy side, it should be the right way up. Now turn the slide around so that you are facing the matt side. A Kodachrome film has a significant relief on its layered side; this is as distinctive as if it had been engraved. The film is very thin in the light areas of the image and somewhat thicker in the darker areas.
Kodachrome scans with ICE dust and scratch correction
High-quality film scanners are characterized by an integrated, hardware-based automatic dust and scratch correction process. The well-tried and tested ICE technology is used in many film scanners. An infrared light source additionally scans the slide and detects dust and scratches by means of mountains and valleys on the film. An infrared beam does not pass through dust particles.
Generally, ICE does not work with black-and-white films. As described at the beginning, a Kodachrome film is basically a black-and-white film that only acquires its colour in the development process. In fact, it contains similar substances (e.g. silver) that also occur in black-and-white films and are impermeable to an infrared beam; the ICE process usually fails because of such particles.
However, with the Nikon Super Coolscan 9000 ED, used by Digitized Memories here at the Gold Coast, a new ICE process with the addition ” Professional™ ” came onto the market for the first time. To our knowledge, the Nikon Super Coolscan 9000 ED together with it’s Digital ICE Professional™ is the only film scanner compatible with Kodachrome film.
Is Ektachrome the same as Kodachrome?
Ektachrome has nothing to do with Kodachrome, even if the two terms sound similar. It is a completely normal film family that is available in different speeds (ISO 100, 200, 400…). Ektachrome film was developed in the normal E-6 process, just like any other slide film. Everything written on this page about Kodachrome films does not apply to Ektachrome films, so they are two completely different pairs of boots.
The same applies, by the way, to other similar-sounding films like Agfachrome or Fujichrome. These types of film are also normal slide films (E-6 development process) and have nothing to do with Kodachrome films.