Digital BW, The Print

I think it's probably simpler than that. Given a pure color -light of a 
single wavelength, say from a laser. Can the values of the R, B, G 
sensors be used to estimate the response of a B&W film to that same 
laser? Most likely not.

However, given a complex scene illuminated by white light, I would 
expect you could come close.

Truman

Jon Dubovsky wrote:

> >
>I think I need to weigh in again.  Perhaps no one read my previous post. 
>*I* understand Anthony, at least on this point:
>
>It is a basic mathematical fact that the process of binning is *not* 
>reversible under almost all circumstances.
>
>Let's say that we have a spectral input of amplitude A(F), where F is the 
>frequency.  Let's take two simple response functions (the same applies to 
>three, but I the extra lines clutter things up), r(F) and g(F).
>
>If we take two binning functions to collect r and g...
>R = integral over all F of (A(F)*r(F))
>G = integral over all F of (A(F)*g(F))
>
>Look at those last two equations.  If I give you the result of the 
>integral (the R value, for instance) and the r(F) response function of the 
>filter/CCD combination, can you tell me what the input A(F) is?
>
>Answer: for all but the most trivial A(F) and r(F), no.  For an arbitrary 
>A(F), never.
>
>More simply:  if you know the exact spectral response of, say, the red 
>element of a CCD sensor, and I tell you I got a red value of 130, can you 
>tell me the original spectral input?
>
>Answer: no.
>
>  
>