The Grass is Always Greener When You Pump up the Saturation in Photoshop
Everyone like to look at pretty pictures, and bold, vibrant colors tend to look pretty. So, what's the problem?
Back in days of yore when photographers shot images on film rather than digitally as we do today, it was generally understood that images should accurately reflect the appearance of the scenes they represent. Surely, there were exceptions to the rule. There have always been trailblazer photographers who have attempted to push the bounds of creative expression using various "special effects" during developing and printing. But achieving good results with such techniques wasn't easy, and few photographers even wanted to try.
Photography was a medium for recording memories of what was, not what was dreamed of. Back when the American West was opening up, photographers took their cameras west too in order to show what was there for those who couldn't join them on the journey. Painters produced likenesses of the West as well, but it was photography that was considered truth. Back then, any image of sights such as Yosemite Valley or Monument Valley in the American Southwest were rare, and miraculous. No one felt much need of augmenting what they saw. Even once color film was introduced, it was enough for an image to be in color instead of merely black and white for it to stand out. Accuracy was still paramount.
But as time when by, the number of photographers and photographs continued to increase, competition naturally increased. Improvements to depth of field via tilt/shift lenses, and better exposure control and wider latitude via push/pull processing and other methods helped, but only so far. When Kodachrome was released by Kodak in 1935, photographers moved to it in droves due to its ability to render color. As a side note, another film did use the name Kodachrome as early as 1913, but it was cumbersome to use and was rapidly forgotten about once the more modern version of Kodachrome was introduced two decades later.
But it was the vibrant color of Fujichrome Velvia, introduced in 1990, that truly took the photography world by storm, cementing the idea of saturation as being a sought-after goal of image makers and image consumers alike. Photographers felt a pressure to move to Velvia to remain competitive and meet the demands of their customers. This wasn't true for all photographers of course. Wedding and portrait photographers in particular still valued accurate skin tones more than vibrant colors. But those who shot landscape images and others were forced to come to terms with Velvia in some way. Shortly before the end of the film era, even more saturated films such as Kodak E100 VS pushed the quest for vibrant color even further. For those who never shot E100 VS, it's worth noting that "VS" literally stood for "Very Saturated." Truth in advertising at least.
Once we all moved to digital, either via scanning the film we shot, or by direct digital capture, it became possible to push saturation as far as one wanted, and to do so at one's leisure in the digital darkroom, after the shutter release had been pressed. The saturation floodgates had been opened for one and all.
Regrettably, restraint was a lesson hard to learn for some, and many images started showing up online that were clearly pushed too far, into an almost comical pallet of overly saturated colors. OK, perhaps I'm editorializing here a tad bit, but I think you'd have to agree, it is possible to go too far, even if not everyone seems to share the same boundary as to just what "too far" may mean.
As a way to help mitigate the problem somewhat, Adobe added a slider for "Vibrance" to their imaging product line roughly a decade ago now. The idea behind Vibrance was to boost saturation proportionally to where it needed it rather than uniformly throughout an image. Areas of an image that that were already fairly saturated would see little change, whereas areas with less vibrant color to begin with saw greater change. So far as I am aware, the idea of Vibrance began with Pixmantec's Rawshooter raw file converter which Adobe acquired with the purchase of Pixmantec in 2006.
When HDR (High Dynamic Range) imaging caught on a few years later, oversaturation gained a new life all over again since many early software programs for HDR tone mapping had a nasty side effect of boosting saturation rather than merely blending different exposures. Thankfully, those days are beginning to fade (along with their garish saturated colors), but one can still find online forums where this sort of comic book color look is seen as a goal rather than a defect.
Yet the lure of saturated colors remains hard to avoid completely as it seems to be psychologically hardwired into the human brain. Set two images side by side, identical in every way except that one has more saturated colors than the other and the average viewer will almost invariably pick the saturated one as being better than its tamer neighbor. This behavior can also pose a strong temptation to boost color when optimizing images in Photoshop, Lightroom or whatever your tool of choice may be. And the saturation bug here is a progressive disease. Bump up the color a little bit when first working on an image, and it will generally improve its appearance. After attending to other aspects of optimizing that image though, and the eye adjusts to this new appearance. A tad more saturation at this point will again seem like an improvement. By making the colors pop more, the image just looks better. Work on an image long enough, and it may undergo several rounds of saturation boosting in an attempt to make it look as good as it can. Lacking any frame of reference to how it looked before any optimization, the saturation bug can run wild with abandon. It could only be after the fact if at all, when it's too late to go back, that one realizes that anything is amiss.
So, if saturation looks good, is any of this really a problem, or should we simply accept it as part of optimizing images? As tempting as that might sound at first, saturation isn't all rosy despite how vibrantly red those rhetorical roses may be.
Digital images are generally stored in RGB mode with a set of three numbers representing respectively red, green and blue components. To produce a more saturated red for instance, you would need to employ higher values for the red channel component. Similarly with green and blue. That is to say, if you force all color in an image to be saturated, you would limit the range of values employed for the three color channels to only the upper end, thereby disproportionately neglecting the lower end of each channel's range of possible values. But those values also serve to represent contrast, and detail. And the appearance of sharpness stems from the adjacency of contrasting colors or tones. By restricting one's self to only some of the range of possible values in the quest for vibrant, saturated colors, you would also limit the ability of the RGB system to fully represent the possible range of contrast and ultimately sharpness. Granted, moderate increases to saturation during image optimization would have only minimally apparent effect on contrast, but the effect is real nonetheless.
Moreover, it's not difficult at all to push color far enough so as to clip at least one channel while increasing saturation. To use roses again as an example, this time real ones rather than merely rhetorical, it's not uncommon to completely blow out the red channel, with just the green and blue remaining to preserve any appearance of detail and contrast. Looking solely at the composite histogram will give you the erroneous impression that all is well. But even a brief look at the per-channel histograms will reveal that the red channel is overloaded with no detail remaining. Saturation is not free, and there are limits to what can be done safely.
There's a well-known expression that the grass is always greener on the other side, the inference being that one isn't satisfied with what they have, and that their situation can always be improved upon with change. As we all learn at some point, this idea, while sometimes true to an extent, can't possibly be always true. The same lesson should be kept in mind when optimizing images. Saturating the green color of grass (or the color of roses or anything else for that matter) does, or should, have limits. Reasonable discretion matters, and there is a price to be paid for abandoning color accuracy.