Here are my notes on the individual images. This exercise was more instructive than I expected and I hope we all picked up some good pointers. As I noted earlier, this particular image isn’t especially advantageous for PPW. As you’ll see, many of the better versions hardly used Photoshop at all.
601 Chosen for the par version. Foreground color choice perhaps too brown. The choice of purple for background is unusual but effective. I think this is our best version for separating the Colosseum from the background, without wiping out our awareness that there is a big city behind it. Paco Márquez used only Capture One to prepare this image, justifying my prediction that PPW is not really advantageous in this particular image.
602 Snowy and washed out.
603 Good presentation of Colosseum but the background is rather busy. This came about when the person used a variant of the Bigger Hammer action to bring out shadow definition. The result is great detail in the background cityscape, but most people don’t want that. See #613 for how this idea might have worked better.
604 Interesting sensation of warmth, caused in Camera Raw by a move to warm the sky, in the course of an otherwise simple procedure.
605 Contrast between Colosseum and background, perhaps too much, compare to #601, foreground an unattractive color and Colosseum too neutral. The written explanation states, “I assumed the walls are gray-colored, so if that’s not true (if they’re a pale reddish or something) my version may be way out of whack.” And so it is. An image search will reveal that the Colosseum is distinctly warm.
606 This is like #601 but taken too far IMHO. David Kessler, who prepared this outside of Photoshop (perfectly OK by our rules) states that a certain amount of detail was lost when he brought the file into Photoshop for export. I don’t know how this would have happened, possibly a profiling issue.
607 Dreadful cold cast.
608 Reasonable luminosity but looks like a grayscale image, needs color somewhere.
609 Chosen for the par version. This striking effort is from one of the MIT retouchers. Its dramatic effect largely depends on two tricks: an emphasis on the spotloghting at right of the Colosseum, and the addition of color in the buildings at background right. Without either of these steps the image becomes dark and boring. Also, the foreground is handled well, it is attractively warm without drawing attention to itself by too much contrast or too bright an orange. To see the importance of the color choices here, compare it to the next one, #310.
610 It is fortuitous that this one comes right after #609, to which it similar in the handling of contrast. The person preparing this, however, decided that a blue haze in the background was a bad idea, and neutralized it. Blend #609 into it, Color mode, and things are much better.
611 This was my first attempt to make an entry for this case study and eventually I threw it out and started over, couldn’t even use it for blending. For some reason I decided that the foreground trees were critically important, so I went into Camera Raw and jacked up shadow detail. This did get better trees but it also emphasized the background city too much and gave the Colosseum a certain rough feel that isn’t appropriate for a 2,000-year-old stone building.
612 This person favored a more neutral sky and felt that his was too light, so he darkened it through a mask. He did not do the corollary, which was to lighten the center of the Colosseum, so the overall result is too dark and too flat.
613 This excellent presentation differs from most in that it makes the left-hand side of the Colosseum darker than the surrounding background rather than lighter. Both ways work. The key step here appears to have been the application of the Equalize command midway through the process to the red and green channels. This created more detail in the background city than others wanted, but it was handled more attractively than in #603.
614 Pleasant dark scene, possibly too magenta? The person had applied the skin desaturation action in an effort to tone down some of the oranges. The result is similar to #612 except that the midtone is lighter. That’s fine, but the sky should have been darkened separately if need be.
615 Here there was an attempt to force color into the shadows, which worked, and the highlights, which is more questionable. It’s a nice enough presentation, but #609, which is along the same lines, shows how it could have been better.
616 Nice presentation, colors not particularly interesting The person felt that early in the process the scene was too red, likely this was bad judgment.
617 Chosen for the par version, the favorite of many commentators. Spectacular rendition, possibly blown out in a few places, captures the brownness of the Colosseum as well as the spotlight effect. The color was absolutely needed, other people were too gray when they were this light. Robin Mark D’Rozario writes, “I wish I could claim intent for the luminosity range of my submission, 617. It was more happenstance and luck. The submission is a blend of three images. One of these was used only for the street and trees so it didn't contribute to the Colosseum and background. Of the other two one has a range of over 72 points and the second around only 41! Without the contribution of the former my submission would have been quite flat. I actually thought that the second image was more balanced and a better choice by itself! A further endorsement for blending images.”
618 This is the averaged version of the five MIT retouchers. As you can see by comparing it to the recently posted #631, which is the average of our 29 versions, we did somewhat better as a group than they did.
619 One of the nicest foregrounds but would benefit from a darker sky; therefore it is somewhat flatter than similar versions. A good representative of the group that preferred not to have a strongly blue sky.
620 Chosen for the par version. This is my “official” entry. I think I could do a better job today after seeing everyone else’s work. I did get a good separation from the background with a trickier version of a method that some others tried. Having been dissatisfied with my efforts in #611, which has a lot of detail where I don’t want it, I discarded it and started from scratch with this one. I got to a point similar to that of many other versions, too dark. So, on an adjustment layer, I found the lightest area of the Colosseum other than the spotlight (which I added yellow too, effectively IMHO) and lightened it drastically. Then, I applied a layer mask based on the pre-curve RGB. To that mask, I applied a U-shaped curve, thus exempting both highlights and shadows from the correction.
621 Brown and unappealing.
622 Another nice darkening of the background, could use a spotlight effect in the front. Compare to 623 which uses the same colors
623 Good ideas, execution not as good as some others.
624 This is my 2017 version. My notes from the time indicate that I was pleased with the foreground detailing. I’m much happier with my newer version, 620, which separates the Colosseum better from the background. Both, however, have the Colosseum a bit too gray. I should have darkened the sky. It looks like I may have just treated this like a routine citiscape and not realized the need to emphasize the Colosseum.
625 Effective, similar to several others. Good emphasis of spotlight. This person started with the default version and mostly worked with Photoshop curves. He went for more shadow detail (not sure that was wise); added a small amount of saturation overall but then some more saturation to the blues, which probably was good for the background and not so good for the roofing at foreground right.
626 Excellent contrast, somewhat overwhelmingly orange, which makes it a bit monotonous in comparison to the somewhat similar #617. Tom Hurd posted a complete description of his steps but allowed that he had spent 3+ hours on the image, summarizing his results:
627 Chosen for the par version. Interesting use of background colors, good spotlighting, foreground a little foreboding. The person notes, “this was a hard one primarily because it was hard to figure out what to do with the color. The default version had a very orange feel to the street lights, but I felt like that give the lit areas too much of a monochromatic lok without any color variation. Cooling things and shifting the warm areas toward yellow still looks ‘correct’ bue allows for a little bit of rosy color to come in to the buildings.” He used an inverted A channel in Hard Light mode to lighten the green trees; he also generated a CMYK version in order to have a fake black channel available for various uses; this is a variant of the H-K action, which can, if you wish, save an ersatz black channel for blending.
628 Looks almost like a grayscale version.
629 A nice rosy-purply feel, needs more snap in the Colosseum. Little spotlight effect at all. He did most work in Camera Raw, but after converting to sRGB for what he thought was the final result, he decided that the background was too blue and toned it down. That would have been a good time to make the sky darker, too.
630 The par.
631 (added later, not in download) an averaged version of 601-629.