Tuesday, June 7, 2011
See In Black & White
How to understand the role of color contrast in black-and-white conversions to make your best images starting at the moment of capture
|This Article Features Photo Zoom|
Figure 3: This shows the sRGB gradient colors plotted in the Lab coordinate space in Color Think. The "L" scale for Lightness is the vertical axis in this coordinate system, so colors with higher lightness values appear higher in this space and those with lower lightness values, such as the blues and reds, appear lower.
By using the L values in the standard grayscale conversion, Photoshop uses a model that's based on how our eyes actually respond to the brightness of different colors. But not all of the processes choose brightness values in the same way, and it's the brightness values that determine color contrast.
Figure 5: Here's what happens to the same pure colors when they're simply desaturated using the Hue/Saturation dialog in Photoshop. Because Hue/Saturation works in the HSL color model rather than in Lab color, the very saturated colors in our gradient are all rendered as middle gray.
Beyond the standard grayscale conversion and desaturating in Hue/Saturation, there are countless other techniques for creating black-and-white in Photoshop. On top of that, there are countless plug-ins out there, each claiming to possess the magic elixir that will make your black-and-white conversions "unique." But by far, the most important aspect of making good black-and-white representations is color contrast. And the raw controls that we now have in Lightroom and Adobe Camera Raw make creating great color contrast a piece of cake.
Let's take a look at two very different examples of this. Figure 6: First, in this photo of the restaurant front, we have an image that contains colors in nearly every one of Lightroom's color luminance ranges.
There are two starting points for black-and-white in Lightroom's HSL tab. Figure 7: When you first convert to black-and-white, the default behavior gives you the Auto mix. The Auto mix generally darkens the greens and yellows and lightens the blues and purples, but the actual mix that you get will be different with every photo. Auto always tries to give you the best color contrast that it can.
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