Farmhouse and Dogwood
by Scott Rosenberg © 2005 for largeformatphotography.info
Introduction:
The
digital workflow is pretty much ubiquitous in the world of fine art color photography these days. The
technology has gotten so good that we are now able to produce prints with a vibrancy and clarity never
before possible. Modern scanning and printing technologies have gotten so good, in fact, that for the
first time since slide film has been available, prints are actually starting to rival transparencies. While
reflected media will never look exactly like transmitted media, the digital workflow of today is enabling
photographers to produce prints closer to their originals than ever before.
After seeing what was possible with the new digital darkroom, I quickly embraced the workflow for my color
printing. Initially, however, I was less enthusiastic about making black and white prints using these same
technologies. To my eye, I still preferred prints made in a traditional darkroom. However, after recently seeing
black and white prints from the latest in digital printing, I feel like that gap has been bridged considerably,
and set out to determine how best to scan black and white negatives using my Microtek Artixscan 1800F.
To gather a list of best practices, I spoke to several photographers whose work I admire and who are printing
black and white images from digital files made from film. While most are using the same scanner as I, their individual
methodologies shared little else. I therefore decided to start from square one, consider every possibility
I could think of, and let the results speak for themselves. It should be noted that there will always be sources
of variation that can not be controlled, and my findings are specific to the equipment, myself included, in my
personal workflow. In other words, your mileage may vary.
Experimental Design:
Having
not much else to go on, I decided to scan a sheet of black and white film every way my scanner was capable of:
1. As a Black and White Negative
2. As a Black and White Positive
3. As a Color Negative
4. As a Color Positive
Since I set out to determine the scanning workflow that will lead to the finest print, and not the amount of
input required post scanning, I worked with each file until I got that individual image to look just as I
would want it to before having it printed, taking care to get all the files as closely matched as possible.
Positive scans would have to be inverted; color scans would have
each of their three channels (Red, Green, Blue) evaluated to determine which one yielded superior results.
I worked on each file as I would any other in preparation for printing, and while no prints were made, these
master files were then scrutinized and a best practice was decided upon.
Since I was primarily interested in assessing my scanners capability regarding tone and resolution of fine
detail, I selected the image shown below, as it contains a full range of tonal values, from the deep shadows found
under the porch to the bright whites of the dogwood blooms, as well as some very fine elements in the detail of the
rough-cut timbers and the bark of the trees.
A Comparison of the Color Channels:
The
first thing I wanted to check was if there was a difference in the red, green, and blue channels
in the color scans. Since the final print would be black and white, I could use any one of these
three channels independently of the other two, or use all three simply by converting the RGB image
to greyscale. Shown below are detail scans illustrating each channel, as well as the RGB image
once converted to greyscale.
The green channel, while a little grainier, clearly has retained the most detail. Remember,
these scans represent a very small area of the overall image, and as such, the increased grain apparent in the green
channel is not really a concern, as it will be completely undetectable in the final print.
Now that the sharpest channel of the color scans has been determined, we can take a look at how the black and
white scans compare to the green channel of the color scans.
Detail Scans and Conclusions:
Having
determined that the green channel from the color scans was in fact the sharpest, I now set out to compare it
to the black and white scans. Shown below are detail scans illustrating how the black and white scans
compared to the green channel alone of the color scans.
These scans are slices from the tree to the right of the farmhouse. The slices from the color
scans clearly show more texture and detail than those scanned as black and white. It is difficult to tell at this
size, but when enlarged further, the color positive scan shows the most detail.
These
scans are slices from knotty boards just above the window on the farmhouse. Again, the
slices from the color scans are sharper and exhibit more detail than the black and white scans, with the color
positive scan showing the most detail when enlarged yet further than what is shown here.
As can be seen in the detail images above, there was little difference observed in the tonal
range of the scans. There was, however, an appreciable difference in the amount of detail captured, the master
file containing the most detail comes from the green channel when the film was scanned as a color positive.
This surprised me, as these are the settings farthest from what was actually scanned - a black and white negative.
It was my initial belief that scanning the film as a black and white negative would yield the best scans. So
surprised was I by these findings that I duplicated this experiment with an entirely different black and white
negative, this second experiment returning precisely the same results.
For my particular workflow, that is to say my scanner with me at the wheel, the best scans of black and white
negative film are obtained by scanning the film as a color positive, inverting the file, and then using only
the green channel.