Selective Masking Part III: Computer Techniques for the Traditional Darkroom

By Alan Ross Back to


Part I (Nov/Dec, 2010) introduced an inexpensive, low-tech technique for hands-free dodging and burning of an image by using pencil or markers on mylar masks placed above the negative in a traditional darkroom. Part II (March/April, 2011) introduced the use of Photoshop or Elements to create masks on inkjet transparency film to make hands-free graduated-burns of skies and other areas. Part III expands on the use of the computer in the traditional darkroom for making prints with multiple contrasts on variable-contrast paper.

All three articles explain how to make a variety of masks to achieve controlled results while printing conventional negatives on silver halide photographic paper in the darkroom. Other important requirements: These masking techniques require use of a diffusion enlarger or contact printing, a special, inexpensive, negative carrier, a computer with Photoshop or Elements, a scanner that preferably will scan film, an inkjet printer capable of printing on transparent media such as overhead projection film available at most office supply stores.

One of the greatest technological advances for the darkroom enthusiast was the introduction of variable- contrast papers. Not only were they great for the bank account, since one package would suffice for any given size instead of three to six, but it became possible to have more than one contrast in a single sheet of paper. Some of the procedures typically relied upon for multi-contrast printing, while ultimately producing the desired result, require the use of special auxiliary printing filters or enlarger settings which have to be changed for one action, then reset to original status for subsequent prints. Time consuming at best, and occasionally aggravating.

So far, we have applied Selective Masking techniques ranging from a low-tech “I just want to make these rocks a bit lighter” to computer-savvy methods for a smooth, graduated sky-burn. Now it’s time to take the techniques discussed in Part II to the next level. We are now going to go from Grayscale to RGB−kind of like the BW-to-Technicolor segue in the Wizard of Oz.

(Figure 1) First rough print
(Figure 2) Selecting 100% magenta

Simple Multiple-Contrasts

I adjusted exposure and contrast to get the room interior to look the way I wanted, the terrain outside the windows became mostly paper-white, as did the glare on the window frame and floor (see Figure 1). Since I have dealt with this sort of situation before, I had a pretty good idea that a burn-in at the basic print contrast would produce a rather harsh quality rather than the more delicate, dreamy quality I wanted. I would need to burn the highlights in using a lower contrast than the contrast for the interior. Keeping in mind that Selective Masking is controlled dodging, meant that to accomplish this I would need to make a higher contrast mask for the room, with the windows, etc, being clear. That would let me reduce the contrast in the enlarger to offset the now mask-increased contrast in the room. That, in turn, would cause the windows to get more exposure than the rest of the image, AND at a lower contrast.

Since I already had a 300dpi grayscale scan of the whole negative, I didn’t need to pull the negative from the carrier and take time to make a mask scan. As I always do, I started out by making a Reg Marks Layer (See Part II) indicating the image corners. Because it takes color to make a contrast change on VC paper I next converted the file from grayscale to RGB (File>Mode>RGB, do not flatten Layers).

My approach to this mask is exactly the same as for same—contrast masks—the only difference being that instead of a Black Layer modified to gray, I will use a color: magenta to burn in with a lower contrast, or yellow to burn in at a higher contrast. In this case it will be magenta. Just as with the examples in Part II, the areas to be burned in will be in appropriately separate Layers with the target areas painted or filled in with white.

Since, just as with the Black Layer in the earlier examples, we can adjust opacity from 100% to Zero, we want to make the base Layer 100% magenta. Click the foreground box color in the Tools window and a Color Picker will appear. In that window, you will see boxes for C, M, Y and K with some numerical entries. Enter “0” for C, Y and K, and “100” for M. Click OK. The foreground box in the Tools window will now be magenta (see Figure 2).

Create a new Layer and position it just above the Background Layer. Select All and choose Edit>Fill >Foreground Color. You now have a Layer that is pure magenta.

Next, we’ll do a burn Layer for the windows; I’ll do the window frame and floor spots in a separate Layer so I can control them separately. I made the Background Layer active and used the Magic Wand to shift-select the windows, getting them all in the same selection. In the Quick Mask mode I could then see all areas that needed additional selecting or deselecting (see Figure 3). Exit Quick Mask.

(Figure 3) Initial window selection with the Magic Wand
(Figre 4) Test files made with magenta and yellow patches set at warious opacities. The patches were then compared to a set of color printing filters to estimate the approximate color correction values.
(Figure 5) The final mask

I then created a new Layer called Window Burn and filled the selected areas with white. Next, I did the same thing with the window frame and floor spots, creating a new Layer called Floor and Window Burn.

I wanted the floor elements to burn in a bit less than the windows, so I dropped the white opacity of that layer to about 80%.

In order to make an approximation of how to set the base magenta opacity, I referred to a sample printout I had made with varying opacities of magenta, then compared the patches to a set of color printing filters. Refer to Determining Opacity Densities in Part II and also Figure 4.

My original enlarger filtration for my basic test print was 20M. It happened that magenta set at 50% opacity with my inkjet film and printer was approximately 20M so that was my initial−and very happily my final mask setting. (This doesn’t always happen!)

With my enlarger’s V54 cold-light lamp, 20M has about the same contrast shift as 30-40Y, so to make the print I removed the 20M and then put in 35Y.

This mask, (Figure 5) in conjunction with some penciling on a mylar sheet (Part I), to dodge some of the deep shadows to left and right of the window, allowed this complicated image to now be printed with only the push of the timer’s button.

In summary:

• If your negative scan file is in grayscale, convert it to RGB and don’t flatten layers in doing so.

Magenta dodges highlights more than blacks− this results in an increase in local contrast.

Yellow dodges blacks more than highlights−this results in a decrease in local contrast.

• Remember that Selective Masking is controlled dodging! If you need to burn-in an area, you need to increase your exposure to get the burn-in value you need then dodge everything else via mask.

Ansel Adams and Georgia O’Keeffe, Carmel, 1976
Ansel Adams and Georgia O’Keeffe, Carmel, 1976. This is an image from 35mm that I was never able to print successfully without getting into multiple contrasts. There was a great deal of flare coming from the window behind O’Keeffe. If I got the contrast right for Ansel, everything else had way too much contrast. If I got O’Keeffe right, Ansel was just a dark gray mess. This mask essentially allowed me to make the print using four different contrasts. The sky area printed at the basic contrast set in the enlarger. Magenta dodges whites more than blacks, so contrast was increased in that area. Yellow dodges blacks more than whites, so contrast was decreased in that area. The mix of magenta and yellow simply dodged that area without much change in basic contrast. I still had to do some traditional burning and a bit of pre-exposure, but the mask gave me the contrast control I needed.

Having used Selective Masking in one form or another for maybe 25 years, I have to say that it has completely changed my approach to printing. I can control the densities of multiple areas, small and large, that I could never dream of dealing with before.

Ansel would have loved it, too. When we were making prints for his Portfolio VII in 1976, one of the images was Cemetery Statue and Oil Derricks. It was basically easy to print, but the statue’s face needed a slight bit of dodging. As much of a master printer as Ansel was, we probably threw out half of the prints he exposed! The Los Angeles sky behind the statue was a clear blue (!!!!) and a fraction of a second’s hesitation in moving the dodging wand resulted in streaks in the sky. A second of lingering too long with the wand over the face resulted in a sickly pallor. If I had only thought to replace the back sheet of glass in the negative carrier with a piece of opal-glass or diffusing plex, he could have taped a piece of mylar over the image, added a touch of pencil density and been master of his printing desires!

And now it’s your turn to deal with troublesome images you could never master before! Have Fun!

About the Author

Alan Ross
Photographer and master printer Alan Ross has been Ansel Adams’ exclusive printer for over 36 years. His experience includes operating a commercial studio with projects ranging from ad campaigns to murals for the National Park Service. Since 1993, he has devoted his energies to his personal work, teaching and work for select clients, including Boeing, Nike, IBM and MCI. His photography hangs in collections and galleries throughout the country and internationally, and he has lectured and led workshops in locations from Yosemite to China. For a more in-depth discussion of Ross’ masking process, visit his website,