In my last post, I described a basic workflow for using Lightroom to produce black and white images from color originals. In general, the process is simple and problem-free, but there are two specific areas where problems have arisen and suggest some strategies for working with them.
The first problem is easy enough to explain, if you have a smooth gradient from one hue to another, such as the pink-to-purple-to-blue transition of an earth shadow, you may need to exercise restraint and caution with the Grayscale Mix controls. It’s fairly easy, particularly if you use large or very differing adjustment values for the different hues in the gradient, to end up with unnatural looking results. In most cases, this is easy to fix, once you actually notice it, by careful adjustment of the sliders, but occasionally it won’t be, and you’ll have to resort to other techniques (perhaps the gradient filter tool, or working the image with other tools in Photoshop) to realize your vision.
The second problem is noise. Sometimes strong adjustments to the Grayscale Mix sliders will really bring out noise in an image, I often run into this when darkening skies. Noise reduction can help here, but, there’s a catch…
A third problem is trickier, a longstanding issue in black and white conversions in Lightroom, as well as Adobe Camera Raw, is a set of artifacts that often crop up along edges of images you’d applied strong Grayscale Mix adjustment effects. Below, I’ve included a 100% crop of a detail along the top of the mountain from the example in my previous post.