By Richard Lynch
Question:
I'm a black-and-white enthusiast from my film days. I've just been using Photoshop to desaturate color images, and that doesn't seem to give great results. Is there a better way to convert from color to black-and-white?
The Short Answer:
Leverage your color using channels and image tone to make the best conversions to black-and-white.
The Whole Answer:
Conversion to black-and-white can be done in several simple ways like by desaturating, but the simple ones aren't usually the best. I've written whole chapters about black-and-white conversions in Elements books and have created several actions/tools for conversions that I sell on my website (http://hiddenelements.com) and include in books (like my Hidden Power book that you can find in the betterphoto.com book store). But there are several levels of complexity to making good black-and-white--and different quality to results. Lets look at a few conversions using Figure 1 as a starting point.
Figure 1
The first thing you will want to do with any image you are converting is color correct it. This may seem odd, but you want to have the best source to work with. We look at color correction in all of my courses on different levels (Photoshop 101, From Monitor to Print: Photoshop Workflow, and Leveraging Layers).
The "Desaturate" method of converting to black-and-white is the most basic conversion, and probably produces some of the least favorable results. You can do it as a one step command (Enhance>Adjust Color>Remove Color), and that does the same thing as creating a Hue/Saturation adjustment layer and lowering the saturation to -100. The result would be like Figure 2.
Figure 2
Better methods for converting to black-and-white are based on extraction of image tones. For example, you can do a Luminosity extraction (covered in more depth in my Leveraging Layers course), which is essentially:
- Create a new layer at the top of the layer stack and name it Luminosity.
- Press Command+Option+Shift+E / Ctrl+Alt+Shift+E to copy visible to that layer
- Change the layer mode to Luminosity
- Create a new layer below the Luminosity layer in the stack.
- Merge Down (Command+E / Ctrl+E).
This isolated the brightness of your image and more accurately reflects what you might expect to see over desaturation. You can see the result in Figure 3.
Figure 3
Other increasingly complicated and better methods include separating RGB components and combining them in different ways. My favorite option combines luminosity (33%), red (lighten, 60%), green (duplicated, Screen 70% and Screen 100%), and blue (Overlay 16%) channels. The process is a bit complicated (over 100 steps in Elements), but I have made Actions (a type of script used with Photoshop and Elements) to simplify the process to a click. You can find them on my websites: http://hiddenelements.com, or http://photoshopcs.com. For Figure 4 I did the usual conversion from my actions and then strengthened the Blue channel to 60%.
Figure 4
Other less realistic conversions can be achieved as well, using Channel Mixer, or the new Black & White adjustment tool found in Photoshop CS3. For Figure 5 I used another custom conversion action I created that mimics an Infrared effect.
Figure 5
Converting to black-and-white is often more art than science, and you can get greatly varying results as shown here. Converting to black-and-white can lead to other explorations, like toning (e.g., sepia), handcoloring, and more. But everything about a good image starts with good capture, good color management/workflow and good image correction! Courses on betterphoto can help you in all these facets.
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