Digital BW, The Print

In a message dated 4/23/02 5:25:21 PM, chervinsky@... writes:

>If you look at the numbers
>carefully, you will conclude as to how shockingly non-linear they are.
> I would have expected, for example that the 50 % reading would have
>been close to 1.7/2 = .85.  The Measured value of around 0.6 is WAY
>off!

You mention that you don't think the paper will make much difference, but the 
chief coulprit in all this is dot gain, which is a paper related function. 
When you cover the entire area, then dot gain does not matter; its all 
covered already. When you place no dots and leave the paper white dot gain 
does not matter either. But at fifty percent dot gain matters hugely. I have 
worked with systems that had a 46% dot gain at the midpoint... meaning that 
printing 50% gray would get you a 96% gray...basicly black. Densitometer's 
specialty is determining dot gain. Print that same ramp on several widely 
differing papers, and see what midpoint values you get... variations of 30% 
are possible.

C. David Tobie
Design Cooperative
CDTobie@...