Saturday, May 21, 2022

On converting digital Color into Black and White ~ One Last Time

Before I pause this blog, I thought I'd reiterate something that I learned about converting digital color to black and white.  

When I used to make prints for other photographers for a living, I always strove to tone richness, creamy whites, and deep/beautiful blacks.  If you look at so much of the modern digital black and white work it can be a muddy mess of yuck.  Sure, current practitioners might not see things that way.  They likely believe their B&W work is just wonderful.    Yet to me I have to ask why is so much work missing that tonal richness we used to have back in the day?

It turns out there's a very simple way of getting back to that classic old print richness and I wanted to write about it again, but Mike Johnson beat me to it.  And he says what needs to be said more clearly and succinctly that I ever could.

Here is a link to his Online Photographer blog article.


Musee des Arts et Metier ~ Paris 2021


I now know that processing digital files can be more flexible and more accurate in black and white imaging than film ever was.  And, with a bit of knowledge, we can achieve that old silver print "richness" that so much of the current digital B&W is lacking.  

It comes down to this two things.  First, humans see color tones in black and white in a specific way and, second, the material properties of silver halide papers and their effects on printed from negative images are rather different than people might think.

First, the way humans see color converted to black and white is very interesting.  Tim Soret does an excellent job of explaining what we "see." What human perception modeling allows is tonal separation.  Let me say this again, with emphasis: What human perception modeling allows is tonal separation.

This used to be the Holy Grail of black and white film photography.  In digital work to touch that Holy Grail of tonal separation is as simple as understanding which tool to use and why.


Musee des Arts et Metier ~ Paris 2021


As a side note, I was happy to see that Sony's in-camera black and white conversion fits M.Soret's description of human perception.  When I set a Sony mirrorless camera up for black and white, I can see the effect in the EVF and on the LCD.  Sony has done an outstanding job of eliminating much of the guesswork.  A photographer can really "see" in black and white.  It's so easy it sometimes feels like cheating.

My second learning about converting digital color to black and white is related to what I used to experience when I was a black and white print technician working on Sunset Blvd in Hollyweird, CA back when dinosaurs roamed the earth.  Exhibition quality prints we used to make for at the time famous photographers were nearly always creamy smooth/rounded in the high-tones and raised elevated in the mid-tones of a negative.

It's most definitely not sufficient to take a black and white negative, scan it and invert it to generate a positive image and call it done.  

The negative was always only part of the process, the starting point.  Further, if we stop at the black and white film negative, we're once again stuck in a sea of muddled yucky grays.  It's no better than performing a simple de-saturation of a digital file.  So how do we get around this and come closer to creating the tonal richness of old film-era prints? 


Musee des Arts et Metier ~ Paris 2021


Following Mike Johnson's guide, open the "curves" function in your photo editor, grab the middle of the curve, and lift/raise it.  Watch what happens to your image and stop lifting/raising the curve when the effect is correct.  Here is what M.Johnson says about using this approach.

"...[It]increases shadow contrast, raises the often radically lowered middle values, and softens the contrast of highlights, all at once. This is just B&W Tonality 101..."

To cement this learning we can look at old prints and study their tonal ranges.  We can "calibrate" our eye to the "richness" of tones and expressions that can be achieved.  M.Johnson suggests browsing a site called "Shorpy."  Indeed, studying photos there can be educational and inspirational.

Once you "see" the difference between a muddle mess of grays image and beautiful tonal expressions you'll know what to do.  Just follow these two steps: 

1) Use luminance/human perception modeling to perform the initial conversion from color into black and white

2) Raise the mid-tones using the "curves" tool


Musee des Arts et Metier ~ Paris 2021

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