Digital BW, The Print

Hi 

The whole point is to measure apples (matte ink on matte paper) with oranges
(photo ink on photo paper) but with a light source that doesn't bias one
over the other ie a fair test.  A sphere densitometer takes the surface
texture off the table so to speak because the light is coming from all
angles.  Then you have a measure of dMax that is comparable and we can see
if your matte ink and matte paper "hills and valleys" produce a better
result than the properties of photo black ink on "photo" paper.   I would
still expect the photo combo to show a HIGHER dMax because I think it simply
absorbs light better.  You are arguing that matte paper would have the
higher dMax.  If anyone has a sphere densitometer it can be tested quickly.

Steve


> From: dlruckus <dlruckus@...>
> Reply-To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Date: Thu, 02 Jun 2005 18:26:23 -0000
> To: <DigitalBlackandWhiteThePrint@yahoogroups.com>
> Subject: [Digital BW] Re: Matte versus glossy Dmax: a matter of physics?
> 
> Hi Steve.
> 
> Perhaps I'm not understanding your reference to a sphere instrument
> but it would seem reasonable to think that perfectly diffuse lighting
> on both papers (assuming identical ink on both as otherwise your
> measuring apples and oranges anyway ) would simply tend to subdue the
> difference in surface characteristics. If this is done, so long as you
> had equal ink laydown,thickness and coverage etc you would get
> equivalent measurements, none of which would be fully accurate in
> regards to actual ink absorption of light. After all, the ink's
> absorbtion properties aren't affected by surface gloss. Or is what you
> are proposing just that? That the different surface characteristics
> effect some chemical change to the ink?
> 
> It is even possible under those conditions that the matt surface might
> show a slightly better d'max than the glossy due to multiple
> absorbtion from bouncing light around the hills and valleys of the
> matt while being singly reflected/absorbed by the highly specular
> nature of the glossy surface.
> 
> It's an interesting speculation but one unlikely to be tested anytime
> soon.
> 
> Regards
> Duane