Digital BW, The Print

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


--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Steve Kale
<stevekale@b...> wrote:
> I thought the point of this thread was that because matte paper had
a more
> diffuse reflection than "photo" paper that a measurement (stress:
> measurement) of the dMax of that paper was fundamentally biased
because of
> the typical measurement device used (0/45 geometry).  The corollary
to this
> is that in a diffuse light setting the two prints would "look" the same
> black.  (I don't believe they do and believe that photo black on "photo"
> paper is fundamentally blacker.)  Using a sphere instrument one can
make a
> measurement for which the lighting is diffuse.  We could then know
how much
> of the dMax difference is attributable to the underlying absorption
of light
> and how much is due to the difference in surface properties.