Digital BW, The Print

Frank,

Dmax is measured with a densitometer or a spectrophotometer.  Glossy 
and luster papers have a higher Dmax, and matter papers have a lower 
Dmax.  Some of that is due to the fact that glossy papers tend to 
reflect back like a mirror, whereas matte papers scatter the light so 
less reflects back to reach the measuring device.  

Even though the Dmax of a matte paper may be lower, it may "appear" a 
lot darker than it is.  This is particularly true when framed and set 
behind glass.  For matte papers, a Dmax higher than 1.6 is usually 
good enough for a solid black look, but I prefer to get closer to 1.7 
if possible.  When you get below 1.6, blacks can start to look a 
little weak.  

Every paper its own potential Dmax, but this is based not only on the 
paper, but the inkset used.   And even then, you need to get the 
right amount of ink on the paper.  Too little ink will generally 
result in lower Dmax, but too much can also cause fogging, pooling, 
bleeding, and may actually cause the Dmax to drop too.  So, you need 
to get the ink limit set about right for the best blacks.  The dither 
pattern also has an influence.  Ideally, you want no white flecks 
visible under a loupe, and you want just enough ink to give you the 
best Dmax, but no more.  

For color profiles, there are also other considerations, and it is 
often a trade-off.  Sometimes the highest Dmax can reduce the color 
gamut a little, and sometimes maximum color gamut may slightly reduce 
Dmax.  Sometimes, you are lucky enough to get both.  

Like most people, I test each paper using a specific printer and 
inkset to find the best overall compromise.  For B&W, color gamut is 
a non-issue, so you can shoot for Dmax without worrying about 
lessening the color gamut slightly.  With QTR, you print a 21 step 
grayscale and find the step that gives you the very best black you 
can get.  It can be done by eye, but a densitometer or spectro is a 
better way to nail the best settings.  

I have some matte papers that measure a fairly low Dmax (around 1.6) 
but they look fantastic when printed.  I'd like a higher Dmax, but in 
the final analysis, we are after a print that looks great and shows a 
wide, smooth range of tones.  Surface texture, how the ink lays on 
the print, and other factors come into play.  Dmax is one guide to 
help us in the quest for better prints, but can't be taken as the 
only measure, IMO.

Hope that sheds a little light on the subject.  

Lou

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, Frank Jay 
<frankjay02@...> wrote:

>    
>   Any help or comment that will give me a better understanding of 
Dmax, be it measured or perceptual will be appreciated.
>   thanks
>   Frank