Any color adjustment tool, in any software—past, current or future—works (or does not work) based on the control it offers over one or more of the three elements of color: luminosity, hue and saturation. Photoshop users have more than 20 color adjustment tools. There are six go-to tools, eight “exotic” color tools and 11 redundant tools.
Go-To Color Adjustments
There are six color adjustment tools that I shudder to think of living without: Curves, Hue/Saturation, Vibrance, Selective Color, Photo Filter and Black & White.
Curves offers the ultimate control over luminosity; no other adjustment offers such precision over the relative darkness and lightness of shadows and highlights. Using the separate channels, Curves offers the same kind of precision when adjusting hue.
Hue/Saturation and Vibrance are the two essential tools for adjusting saturation. What’s the difference? Vibrance saturates less-saturated colors more and prevents clipping in very saturated values, producing a heavier appearance. Hue/Saturation produces a lighter more intense effect, so use it cautiously; you can quickly clip values, producing an overly smooth, overly saturated synthetic appearance if used aggressively. Similarly, handle its Hue slider with care; it’s really more useful for color transformation than it is for color enhancement.
Unlike the Vibrance tool, Hue/Saturation offers the ability to adjust individual hues without the need for masking. Neither has the ability to selectively adjust the saturation of highlights, midtones and shadows; for this, you’ll need a luminosity mask. Vibrance provides only a very limited ability to selectively adjust colors with different levels of saturation while Hue/Saturation provides none. (For a way to do this, read my recent column “Saturation Masking”)
Photo Filter offers the ability to adjust the hue and, to a more limited degree, the saturation of an image, much like an analog lens filter would do, only much more precisely and flexibly. Though less intense, Photo Filter preserves hue variety better than a Color Fill layer set to a blend mode of Color.
Selective Color trades in subtlety, referencing CMYK adjustments without leaving RGB working spaces. Its ability to adjust the hue of whites, neutrals and blacks, and its ability to mix white and black into other hues, producing reduced saturation tints and shades, makes it unique.
Black & White is the simplest and most powerful tool for converting color to black-and-white, first reducing saturation to zero and then adjusting luminosity based on original hues. It shines brightest when used in combination with Hue/Saturation and when applied selectively with masks in multiple passes.
Exotic Color Adjustments
You’ll see and think about color differently once you use the three most exotic color adjustment tools in Photoshop: Color Lookup Tables, Gradient Map and Match Color. (For more detail on each of these exotic color adjustment tools, read my previous columns on digitalphotopro.com.) They affect luminosity, hue and saturation in complex nonuniform ways.
Color Lookup Tables combines multiple color routines or recipes into a single adjustment, making it easy to create consistent effects across multiple images; it’s most frequently, but not exclusively, used for color grading the many stills in a video.
Gradient Map uses the luminosity values of an original to selectively distribute new colors into an image.
Match Color applies the color values of one image to another, based on a complex statistical analysis of the color relationships in both; it has an added benefit of being able to neutralize strong color casts, such as those found in underwater exposures, without the use of a second image.
There are also five additional exotic color adjustment tools, which aren’t worth using.
While preserving shadow and highlight detail is best done during exposure and RAW conversion, and while you can mask a Curves adjustment to the shadows or highlights, the adjustment tools Shadows/Highlights and HDR Toning both offer occasionally useful sharpening options that Curves doesn’t, in the form of Radius sliders, which potentially makes them more related to detail enhancement than color adjustment.
Cast Equalize (resets dynamic range), Posterize (reduces gradation) and Threshold (reduces all values to pure black or white) go in the really exotic category. They have real uses for very graphic images and for analysis, but offer little that’s useful for photorealistic images.
Redundant Color Adjustments
Part of mastering a tool is learning what not to use. Many of Photoshop’s color adjustment tools are redundant, offering similar control over the same elements of color—with less power and precision. You can simplify your toolset by eliminating these 11 adjustment types from your workflow. (For more on this technique, see my previous column “Blending Channels” on digitalphotopro.com.) Instead, use the tools that give you more control.
• Brightness/Contrast (use Curves instead)
• Exposure (use Curves instead)
• Levels (use Curves instead)
• Color Balance (use Curves instead)
• Invert (use Curves instead)
• Equalize (use Curves instead)
• Desaturate (use Hue/Saturation instead)
• Replace Color (instead, use Select By Color Range and then Hue/Saturation)
• Channel Mixer, Apply Image and Calculations (instead, use Layer Styles to blend channels, with or without a mask)
See the pattern(s)? Two adjustments, Curves and Hue/Saturation, and one layer technique can outperform all of these 11 adjustments.
You can make any color adjustment in Photoshop more precisely target an element of color by using one of four Blend Modes: Luminosity, Hue, Saturation and Color (a combination of Hue and Saturation). Simply change an adjustment layer’s Blend Mode from its default Normal. If, instead, you apply an adjustment directly to an image, immediately after applying it, select Edit > Fade (Command/Shift/F) to change the mode. As a general guideline for all color adjustments, I recommend you make a standard practice of using the Blend Mode of the element of color you’re adjusting, making exceptions when desired.
Lightroom And Camera Raw
Can the separate, but related programs Lightroom and Camera Raw do things that Photoshop can’t? Yes.
While the majority of these two interfaces, which differ in appearance, but not in function, provide controls that are quite similar to, but sometimes more limited than, what you find in Photoshop, they can do three things that can’t be done in the same way in Photoshop: first, White Balance (Curves and Photo Filter are similar, but different); second, Clarity (High Pass filtratio
n is similar, but different); and third, the HSL panel is able to produce luminosity adjustments of individual hues without adverse side effects on dynamic range.
While the precision of the adjustments provided in Lightroom and Camera Raw is often more limited, it’s usually best to do the basic heavy lifting during RAW conversion—it’s less destructive—and then either dramatic transformations and/or fine-tuning in Photoshop.
In the future, if we discover a single interface that allows us to precisely and without side effects control the luminosity, hue and saturation of any range of brightness (L) colors (H) and intensities (S), then we’ll have found the Holy Grail of color adjustment. For now, the Photoshop interface, a product of more than 25 years of continual expansion, is more complicated than it needs to be, but it’s capable of producing magic—so much magic. When you clarify your thinking about color, you’ll find it becomes much easier to navigate interfaces and master color adjustment. Keep it simple. Remember, color only has three elements—luminosity, hue and saturation—so color adjustment is all about controlling the relationships between them, nothing more and nothing less.
John Paul Caponigro, author of Adobe Photoshop Master Class and the DVD series R/Evolution, is an internationally renowned fine artist, an authority on digital printing, and a respected lecturer and workshop leader. Get access to a wealth of online resources with his free newsletter Insights at www.johnpaulcaponigro.com.