Re: Dmax versus process?

From: Dave Soemarko <fotodave@dsoemarko.us>
Subject: RE: Dmax versus process?
Date: Mon, 01 May 2006 11:56:20 -0400

> Agree. And also, in additional to subjective evaluation, we need to
> understand that density alone does not tell everything, even the look or
> "blackness" perceived by eye. A tranmission densitometer simply shine
> (cannot think of the right word) a light source to an area and measure how
> much of the light is reflected. That is all, nothing more, nothing less.

Do you mean reflection densitometer?

> So, if you have a thick layer of colloid (in a non-technical sense) with
> less concentration of pigment, the light needs to travel down the thickness
> of the layer, and the reflected light needs to travel back. Let's say you
> have a density of 1.8. Now if you instead have a very thin layer and heavily
> concentrated pigment, the pigment might block the same amount of light, and
> you might have a density of 1.8, but the look of the two are different, and
> that cannot be told by density alone.

If you use same amount of pigment, and if the paper is sized to
minimize pigment penetration to the fiber, density can be maximized by
using a thin layer packed with finer pigment particles, rather than a
thicker layer or a layer packed with coarser particles.
Received on 05/01/06-10:27:19 AM Z