possible Laser Camera coming from Canon

Started Oct 22, 2009 | Discussions thread
Its RKM Veteran Member • Posts: 3,104
Re: possible Laser Camera coming from Canon

Mike_V wrote:

I know nothing about these cameras, but Lightjet and Lambda printers use red, green and Blue lasers to image the film and the quality and colour is amongst the best that you can get.

That is a completely different issue. In those printers the narrow colour bandwidth of the lasers not an issue since the full colour image is produced by the wide colour bandwidth of the dyes in the relevant layer of the film. The lasers only serve as a means of efficiently exposing the film.

You get the same effect with laser or LED scanners, such as the Nikon series of films scanners. The narrow bandwidth of the laser or LED source doesn't determine the colour bandwidth of the image, which is already recorded in the film dye, but they do provide a very precise means of sampling and measuring the density of the film dye.

In a laser camera, as described, the reflectivity of the object at the laser wavelength is the only measure of the colour of the object. However the colour of the object is the result of its reflectivity at all wavelengths in the spectrum. Unless the spectral response of the object is known, as in the film and dyes of the printers and scanners above, measuring the reflecivity at one wavelength gives absolutely no information about reflectivity at any other wavelength, even those extremely close.

This will result in a form of extreme inverse metamerism. For example, two completely different coloured objects may have exactly the same reflectivity at the laser wavelengths and thus appear identical to the camera. The reflectivity of the objects may be completely different at other wavelengths, hence appearing different colour in white, or broad bandwidth, light, yet to the laser camera they are identical.

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