basic scanner questions
Posted: Fri May 18, 2007 6:24 pm Etc/GMT-1+01:00
While out for an enjoyable visit to Saltwick bay last night, questions of fundamental importance arose regarding scanners. Dave P and I were soon out of our depth, so we resolved the online sages should have a go.
Basically, we don't understand colour management. As far as we know, there is a physicist's definition of what the three fundamental colours are, ie each of red, green and blue have an arbitrary wavelength assigned to them. The scanner's job is then to raster the surface of whatever and work out the percentage of each colour, ie how much transmission there is at each wavelength. So why the heck do we need profiling? Surely every scanner in the world knows which wavelengths to analyse. Surely every proper scanner in the world can quantify the transmission at each of these wavelengths. Why the variation?
Secondly, a good many people swear by profiling. I am quite convinced they have their sanity but I fail to see the method. Isn't it a case that there are just three colours to analyse? Why the need for such a rich palette? Is it really the case that when colours are mixed, the scanner can no longer accurately analyse the pixel? I would have thought band-pass filters to be better than that these days - I assume that is what is used to analyse the colour. I would be very impressed if each pixel were analysed for its full spectrum, although that must almost be feasible at a reasonable rate these days.
Anyway, if you have any explanations that reasonably intelligent, but scanner-ignorant folk can understand, we'd be glad to hear from you.
All the best,
Charles
Basically, we don't understand colour management. As far as we know, there is a physicist's definition of what the three fundamental colours are, ie each of red, green and blue have an arbitrary wavelength assigned to them. The scanner's job is then to raster the surface of whatever and work out the percentage of each colour, ie how much transmission there is at each wavelength. So why the heck do we need profiling? Surely every scanner in the world knows which wavelengths to analyse. Surely every proper scanner in the world can quantify the transmission at each of these wavelengths. Why the variation?
Secondly, a good many people swear by profiling. I am quite convinced they have their sanity but I fail to see the method. Isn't it a case that there are just three colours to analyse? Why the need for such a rich palette? Is it really the case that when colours are mixed, the scanner can no longer accurately analyse the pixel? I would have thought band-pass filters to be better than that these days - I assume that is what is used to analyse the colour. I would be very impressed if each pixel were analysed for its full spectrum, although that must almost be feasible at a reasonable rate these days.
Anyway, if you have any explanations that reasonably intelligent, but scanner-ignorant folk can understand, we'd be glad to hear from you.
All the best,
Charles