DCR Workshop: Post-Processing to Get What You Want
by Joel Shore -  7/29/2011

As photographers, we know the best way to capture an image is to "get it right in the camera." Sometimes, that just isn't possible. Maybe you didn't have the right lens, or the lighting was awful. Perhaps that quick shot you took of your significant other was perfect - except for the street light or tree branch that seems to be growing out of his or her head. Thank goodness for post-processing.

Let's take a look at a photo I made of the main arcade inside the Venetian Hotel and Casino in Las Vegas. If you've been there, this view is standing near the casino, looking toward the hotel front desk area. Shooting this at 5:35 a.m. on a chilly (for Vegas) January morning partially explains the absence of tourists. I was lucky, too. This photograph demonstrates the value of knowing how to properly post-process with Adobe Photoshop.

Getting the shot
The image was captured with a Canon 1D Mark III DSLR and 16-35mm f/2.8L lens, at 17mm and stopped down to an aperture of f/20. The rig was mounted a Gitzo tripod outfitted with a Really Right Stuff 55mm ballhead. The exposure, triggered with a Canon remote, was 13 seconds at ISO 100. I was shooting in RAW. To eliminate camera shake, mirror lockup was enabled.

To make this shot, I first asked for and received permission from the front desk to set up my camera and tripod, so long as I assured the Venetian the image would not be sold as a commercial offering. There wasn't much time, so I quickly set up my tripod and mounted the camera. Unable to set a custom white balance, I opted for the camera's tungsten setting.

As you can see, there are several things terribly wrong in the "as-captured" version. For one thing, the color is just awful (but the lighting levels are wonderfully uniform). The image is flat and lacks contrast. And check out the way those massive pillars are leaning backward. That happened because I tilted the camera up toward the ceiling. If I had kept the camera perfectly level, the pillars would have retained their verticality, but of course, most of the ceiling would have been cut off - and this image is all about the ceiling murals. A specialty tilt-shift lens would have yielded proper perspective, but I did not have one with me at the time. Also, if I had shot a photo of an X-Rite ColorChecker card, I could have used those 24 standard colors as targets for color correcting in Photoshop; alas, when packing for my trip I didn't think that far ahead.

With the RAW Canon CR2 image brought into Adobe Camera Raw, I first set out to make some overall global adjustments. To get the white balance in the ballpark, I used the eyedropper to click on various areas. Two that worked well were the grayish ceiling surrounding the exit sign at the left and the painted balance between the pillars and the curved barrel-vault ceiling. The latter worked better, though it was by no means perfect. Adjusting the white balance tint helped, too.

Other adjustments were made to the Exposure, Recovery, Fill Light, Blacks, Vibrance, and Saturation sliders. There's no rule - I experimented until achieving a satisfactory result (below). Keep in mind that the painted portion of the curved barrel vault ceiling is ivory, not white.

Taking it to Photoshop
After transferring the image from Camera Raw into Photoshop, the first adjustment was to correct the perspective. To do that, I pressed Ctrl-minus on my Windows PC to reduce the size of the on-screen image, then grabbed a corner of that window, pulling to create lots of gray working space around the image. I pressed Ctrl-A to Select All, then chose Edit, Transform, Perspective. I grabbed the top right corner and yanked outward, pulling the pillars back into vertical alignment. The portions of the imaged pulled into the left and right triangular areas became lost from the final image.

After clicking the checkmark to accept this transform, I added some contrast with a curves layer to make the image pop. For other adjustments to the mural, I added a Color Balance adjustment layer, and another layer with a mask targeting the red shields. The statue "sculptures" and surrounding wreaths had an annoying pink tinge; a last Hue/Saturation layer with layer mask was used to desaturate these features to neutral gray.

The marble floor was a separate matter. The black wasn't black enough, and the white wasn't white enough. The rust-colored tiles looked washed out. Each required individual treatment. Doing so meant making a separate adjustment layer and mask for each. The black and white tiles each got a Curves layer. To adjust both the color and intensity of the rust-colored tiles, I created a Hue/Saturation layer with a layer mask targeting only that portion of the floor.

Several cosmetic corrections were made in Photoshop. To fix the unlit doorway at the far end of the arcade on the right side, I copied the door from the left side, pasted it to a separate layer, flipped it horizontally, then moved it into position. Exit signs near the two rear doorways and near the left front pillar were removed, as was a janitor's mop bucket that was peeking out between two pillars. Finally, the overhead valence near the front right of the image, dark due to a burned out bulb, was restored using a technique similar to the aforementioned doors. Copied from the left valence and flipped, the warp tool was called into action to make it line up perfectly.

Total working time was about 90 minutes, much of it due to the intricacy of the layer masks for the floor tiles, and various portions of the ceiling. If I were doing this anew, I'd consider trying a different technique - converting the image into "Lab" color mode, making color corrections with blue-yellow and magenta-green Curves layers, then converting back to RGB color mode.

The comment I most often receive from Vegas veterans who see the large print on my office wall is that they don't remember the colors ever being this vibrant. Exactly!

Photo credit: Images © 2008 Joel Shore. Reproduction prohibited.