Digital BW, The Print

While we B&W types seem to obsess about our print dmax, it's instructive to put the numbers and readings in perspective.  In message 105399 dpgoldenberg33 noted that D=1.57 means that 2.7% of the light striking the paper is reflected.  D=1.7 means that 2% is reflected. To see the extent of the non-linear nature of these density numbers, see the graph at http://www.gravurexchange.com/gravurezine/0804-ezine/ploumidis.htm

I've also been noting that the spectro measurements are, in effect, using side lighting that is much more ideal than most of us have in the real world.  In fact, my 1% spot meter readings of glossy v. matte blacks on the wall indicate the matte blacks are often deeper.  This is contrary to what the spectro readings would indicate.  The spectros are not measuring total reflectance in all directions.  Yet in most real world situations the light is coming from lots of different directions, so total reflectance may be a more meaningful measure (but difficult to do).

To follow up on the significance of the reflective nature of the medium to its spectro readings, I just got a density reading of 1.75 from an ordinary glass mirror.  That's a great dmax from a mirror that reflects nearly all the light that hits it!

Paul
www.PaulRoark.com

I have always found it rather counter intuitive that glossy papers give higher Dmax than do matte surfaces.  The explanation,  restating what I think Paul is describing, is that reflection from a perfectly smooth surface follows Snell's law: the angle of reflection equals the angle of incidence.  So, if light comes in from the side, it is reflected to the other side, and very little of it reaches a point right in front of the surface.  A matte surface is made up of lots of little surfaces facing lots of directions, and so some light always gets reflected forwards.  If we put a piece of glass in front of a matte surface, most of the light from the side is reflected to the other side, increasing the apparent Dmax.

I have always had a preference of the "un-ferrotyped glossy" look, and have been using Ilford Gold Fibre Silk as my "presentation" paper.  But, I like the *idea* of printing on a more natural surface, and I have lately been working with Premier Art Smooth BW.  What I think that I am starting to appreciate is that the loss of deep shadow density on the matte paper is balanced by a greater tonal range in the highlights. Some of this may have to do with the brightener in this paper, but the glossy papers I use have OBAs, too. I think that the relative effect on the highlights is the complement of what happens to the shadows: more light from the sides is reflected forward from the matte paper.

Any thoughts or comments?

David



--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul" <roark.paul@...> wrote:

>
> While we B&W types seem to obsess about our print dmax, it's instructive to put the numbers and readings in perspective.  In message 105399 dpgoldenberg33 noted that D=1.57 means that 2.7% of the light striking the paper is reflected.  D=1.7 means that 2% is reflected. To see the extent of the non-linear nature of these density numbers, see the graph at http://www.gravurexchange.com/gravurezine/0804-ezine/ploumidis.htm
> 
> I've also been noting that the spectro measurements are, in effect, using side lighting that is much more ideal than most of us have in the real world.  In fact, my 1% spot meter readings of glossy v. matte blacks on the wall indicate the matte blacks are often deeper.  This is contrary to what the spectro readings would indicate.  The spectros are not measuring total reflectance in all directions.  Yet in most real world situations the light is coming from lots of different directions, so total reflectance may be a more meaningful measure (but difficult to do).
> 
> To follow up on the significance of the reflective nature of the medium to its spectro readings, I just got a density reading of 1.75 from an ordinary glass mirror.  That's a great dmax from a mirror that reflects nearly all the light that hits it!
> 
> Paul
> www.PaulRoark.com
>

David-

It gets more complex than that.  The glass adds others factors too. I 
won't get into that physics.

If I know where the print will go, I'll print for that lighting. 
However, I don't think any place outside of a gallery or museum has a 
constant light source (deg-K, etc.).  One of my viewing sources is an 
overhead light with tungsten, A Reveal bulb and a warm flourescent on at 
the same time.

The highlight/shadow behind glass is something else you would print 
for--if you know.  But what glass?  The matte print will still diffract 
and refract before bouncing the light back out.  That may cause some of 
the appearance of better "blacks."

Behind glass or not; multiple lighting or not -- I still prefer the 
"richness" of a matte print over the "brilliance" of gloss.

But, that's a battle that will never end.  One thing I would LOVE to see 
is an original Ansel Adams, Minor White, etc. print both out of glass 
and behind it at the same time.

Seth

My undersstanding , I think , is a tad different..Yes what your saying is true regaring the texture but I think it's more about the relationship between texture and the actual gloss..  So were have two different dynamics going on. A mat surface absorbs light so to speak where as a gloss surface reflects it.. For me stepping back a bit texture creates small surfaces that are not perpendicular to a viewer.. so some of these surface which ultimatly reflect light in different directions thus creating what is visually texture.. In the end I think the larger inflience is simply more about gloss or no gloss... That would be demonstrated by simply placing a piece of glass over a matt paper ...regardless of it's texture it will appear as a higher Dmax...Inside of that the smoother the texture on the matt paper surface the higher the visual Dmax will be so the more texture the less visual Dmax.. I think that is because the optimal direction for light reflectance is perpendicular to a surface. In a textured piece many small surfaces are not perpendicular to a viewer.
I think that the goal of achieving a high Dmax is not as important to me as to others.. The reason for that is that I feel it's more about the paper ink combination today.. Visually papers with varied Dmax still maintain the relationship between the colors or shades of black..So the image is still acceptable to us.. I think it's about finding a paper surface that we like and that offers what were after which might be archival properties or teh texture etc.. and achieving the highest Dmax we can on that material while maintianingg the right relationship between the shades.. To me that's the art of it.. not the biggest number if that makes any sense..

jimbo

  ----- Original Message ----- 
  From: David 
  To: DigitalBlackandWhiteThePrint@yahoogroups.com 
  Sent: Monday, October 15, 2012 9:00 PM
  Subject: [Digital BW] Re: Dmax in perspective -- the mirror with a reflective "density" of 1.75


    
  I have always found it rather counter intuitive that glossy papers give higher Dmax than do matte surfaces. The explanation, restating what I think Paul is describing, is that reflection from a perfectly smooth surface follows Snell's law: the angle of reflection equals the angle of incidence. So, if light comes in from the side, it is reflected to the other side, and very little of it reaches a point right in front of the surface. A matte surface is made up of lots of little surfaces facing lots of directions, and so some light always gets reflected forwards. If we put a piece of glass in front of a matte surface, most of the light from the side is reflected to the other side, increasing the apparent Dmax.

  I have always had a preference of the "un-ferrotyped glossy" look, and have been using Ilford Gold Fibre Silk as my "presentation" paper. But, I like the *idea* of printing on a more natural surface, and I have lately been working with Premier Art Smooth BW. What I think that I am starting to appreciate is that the loss of deep shadow density on the matte paper is balanced by a greater tonal range in the highlights. Some of this may have to do with the brightener in this paper, but the glossy papers I use have OBAs, too. I think that the relative effect on the highlights is the complement of what happens to the shadows: more light from the sides is reflected forward from the matte paper.

  Any thoughts or comments?

  David

  --- In DigitalBlackandWhiteThePrint@yahoogroups.com, "Paul" <roark.paul@...> wrote:
  >
  > While we B&W types seem to obsess about our print dmax, it's instructive to put the numbers and readings in perspective. In message 105399 dpgoldenberg33 noted that D=1.57 means that 2.7% of the light striking the paper is reflected. D=1.7 means that 2% is reflected. To see the extent of the non-linear nature of these density numbers, see the graph at http://www.gravurexchange.com/gravurezine/0804-ezine/ploumidis.htm
  > 
  > I've also been noting that the spectro measurements are, in effect, using side lighting that is much more ideal than most of us have in the real world. In fact, my 1% spot meter readings of glossy v. matte blacks on the wall indicate the matte blacks are often deeper. This is contrary to what the spectro readings would indicate. The spectros are not measuring total reflectance in all directions. Yet in most real world situations the light is coming from lots of different directions, so total reflectance may be a more meaningful measure (but difficult to do).
  > 
  > To follow up on the significance of the reflective nature of the medium to its spectro readings, I just got a density reading of 1.75 from an ordinary glass mirror. That's a great dmax from a mirror that reflects nearly all the light that hits it!
  > 
  > Paul
  > www.PaulRoark.com
  >



  
  No virus found in this message.
  Checked by AVG - www.avg.com
  Version: 2013.0.2741 / Virus Database: 2614/5833 - Release Date: 10/15/12


[Non-text portions of this message have been removed]

--- In DigitalBlackandWhiteThePrint@yahoogroups.com, "jimbo" <mrjimbo@...> wrote:
>
> I think it's about finding a paper surface that we like and that offers what were after which might be archival properties or the >texture etc.. and achieving the highest Dmax we can on that material while maintianingg the right relationship between the shades.. To me >that's the art of it.. not the biggest number if that makes any sense.

THIS!!  Makes sense to me!

On 10/16/2012 05:00 AM, David wrote:
> A matte surface is made up of lots of little surfaces facing
> lots of directions, and so some light always gets reflected forwards. If
> we put a piece of glass in front of a matte surface, most of the light
> from the side is reflected to the other side, increasing the apparent Dmax.

Is that actually happening?  I always thought that there is a loss of 
light when glass is put in front of a print, the more when the distance 
from the glass to the print is wider and/or the glass quality is lower. 
Compared to a bare matte print viewed in the same light you will see 
less separation in the shadows but the dynamic range is not altered as 
the paper white will suffer of that light loss too. A Diasec mounting 
with the print front faced is a completely different method that will 
make a matte paper into a gloss paper more or less and then Dmax and 
dynamic range will increase. More light on a framed print should bring 
back the same sensation a bare print gives with lower light, 
anti-reflective museum glass a must then. That is the other aspect, 
glass reflections will interfere more with the shadow parts of an image 
than with the highlights.

>  What I think that I am
> starting to appreciate is that the loss of deep shadow density on the
> matte paper is balanced by a greater tonal range in the highlights. Some
> of this may have to do with the brightener in this paper, but the glossy
> papers I use have OBAs, too. I think that the relative effect on the
> highlights is the complement of what happens to the shadows: more light
> from the sides is reflected forward from the matte paper.

Is matte omnidirectional reflection of the light not creating a simple 
flare on the total of the image? Having a higher impact on the black 
densities of the picture than on the highlights like in all situations 
where flare happens? It is more a diminishing of the total dynamic range 
but more in shadows than in the highlights so no actual gain in the 
highlight separations either. I think profiling based on a linearisation 
made with 45/0 degr. spectrometer + a perceptual algorithm will create 
equal perceptual separation in the tones in almost all paper surfaces. 
The optical geometry of the spectrometers is not the ideal Ulbright 
sphere but not bad either. I have written before that bronzing can 
affect color reading with today's desktop spectrometers but that is a 
more exotic issue.

-- 
Met vriendelijke groet, Ernst

http://www.pigment-print.com/spectralplots/spectrumviz_1.htm
400+ inkjet paper white spectral plots, October 2012:
added Tetenal-Kodak, renewed Ilford-Innova-Hahnem\ufffdhle-Pictorico
soon Bonjet-Permajet-FelixSchoeller-Mitsubishi-Kodak(more)