Laser printers (color ones) are (were?) required to have some sort of built in imperfection because they were too good and could be used for counterfeiting.
I wouldn't be surprised if this eventually is a requirement for cameras, you know, just because law enforcement wants it.
The part of this that I find most interesting is that these have been known since the 90s and in 2005 there was a flurry of interest as some of the schemes were decoded, but I have never seen an authoritative reason why they are there. Does some entity in the US government require them? By what legal mechanism? Are the printer manufacturers trying to avoid liability for manufacturing counterfeiting equipment?
> At that time, printers already printed yellow dots with the serial ID.
No schools in 1987 had color laser printers with this technology (and I doubt many businesses did either). Any students trying to do something fishy would have had to make do with, at best, 24-pin dot matrix printers with color ribbons.
I suspect that there are a lot of people with kids in school and various other use cases where color printing isn't really optional. (Though color laser isn't all that unreasonable these days.)
Is it? Soho color laser printers are calibrated and designed to print color documents, not photos. They use CMYK (4) colors and inkjets designed for photos use 6 or more. It's possible to do photos with it but generally the laser printers most people have are not really designed for high quality photo (where a cheaper inkjet would be), they will show banding and be less color accurate.
You'd think laser printers would be prior art - a rotating mirror (usually a hexagon) was exactly how older laser printers would scan across the drum to form out the print.
I wouldn't be surprised if this eventually is a requirement for cameras, you know, just because law enforcement wants it.
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