Re: soft-proofing shadows
Re: soft-proofing shadows
- Subject: Re: soft-proofing shadows
- From: Roger Breton <email@hidden>
- Date: Sat, 19 May 2007 19:13:07 -0400
Hello Eugene,
> I assumed that a light source could not reproduce black as effectively as ink.
Well, it is not so much the light by itself, as you noted below, but the
combined effect of light + no light, i.e. white point and black point on a
monitor usually form a higher dynamic range or contrast than a print.
> My monitor, though it
> appears to be able to display black in ambient light up to about EV 4, in
> total darkness its maximum black appears as pale grey.
Isn't color "relative"!
> I assumed if there
> was light emitting from my monitor while it was displaying total black it
> could never fully achieve black.
True. Maybe not black but some black.
> On the other hand, since my concern is more about the separation of tones
> along the curve it might not be so crucial that the monitor black point be
> precisely the same L* value, since the luminance values of the print will
> vary with illumance.
The apparent contrast of the print does vary with illuminance and how dark
are the black on the print and how white is the paper itself.
I suppose it's possible to determine the contrast range of a monitor and try
to transpose that range on a print, to find some objective basis of
comparison. If I had a luminance meter, I suppose I could measure the Y of a
monitor white point and the Y of a monitor black point. That could give a
figure like 100:1, for instance. Now, the same assessment can be carried
over a print, using the same instrument, to yield a similar contrast ratio
figure. Say 50:1. I am just making number up. But then, knowing that
information, what judgement would you make on the reproduction? Would that
help you better analyze the tones in the shadows?
> It might be more crucial to compare complete dynamic range. The monitor will
> most likely have a greater dynamic range, and therefore even if its black
> point is lighter it could compensate by exploiting the space in its upper
> range to preserve increments in brightness.
True. I don't know if that is how things are done inside an ICC profile? I
tend to think that tones are mapped "linearly". One would need special
software in order to achieve the smart use of the tonal range you describe.
This, by the way, is how colors are converted from RGB to CMYK when using a
good perceptual rendering. Tones are just not slapped from Source to
Destination, a smart profiler will do some kind of smart tone compression
during the conversion.
> Is this what makes you say that a
> monitor black point is deeper or is it truly transmitting a lower brightness
> value when compared to the maximum black reflective densities viewed under a
> standard iluminance?
No, I was refering to the contrast ratio of a monitor who is typically, in
my experience at least, higher than that of a print.
> Eugene Appert
Regards,
Roger Breton | Laval, Canada | email@hidden
http://pages.infinit.net/graxx
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