Digital BW, The Print

I just tend to use L* (and not density) in thinking about how black or white
something is.  But there are reasons why density is worth knowing.  If you
plot the log function you see immediately that its shape is characteristic
of the eye's response to increasing light intensity.  Also, one unit on a
log10 scale is 3.32 exposure zones.  So if you know dMin and dMax then you
have a sense for how many f-stops of dynamic range you have.  The best
reading I have found for this stuff is Normen Koren's site:

http://www.normankoren.com/

Particularly the sections on "Monitor Calibration and Gamma" and "Tonal
Quality and Dynamic Range in Digital Cameras".  It ties the analogue and
digital components together.  Some of it is heavy but it's worth persevering
- even if you have to take good breaks from it, try to go back as you'll
slowly see stuff fall into place.  Site's like Bruce Lindbloom's are full of
formulae and calculators which are useful from time to time but Normen's
site has more of the "why".  The only book I have found useful is Bruce
Fraser's Real World Color Management which is deliberately low on the maths.


> From: Tony Riley <listsubs@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Sun, 30 Oct 2005 15:59:58 -0000
> To: <digitalblackandwhitetheprint@yahoogroups.com>
> Subject: Re: [Digital BW] Black Density measurement
> 
> Thanks both to you and John Moody for setting me off on the right path.
> I have the Eye1 Pro and am using the Eye1 Share package to measure colour
> patches but it is inevitably a long learning curve from producing working
> profiles to understanding exactly what is going on "under the bonnet".
> 
> The reason for my request was that I am testing various papers to see which
> give the richest(most dense) black. I am quite surprised at the range and
> just how poor even some gloss papers are at good black reproduction.
> 
> Given that there is a fairly constant translation formula between L* and
> Density why is D considered preferable to L as a unit of definition?
> 
> Any good books out there that might make a good read in the bath? <grin>
> 
> TonyR
> 
>