Technique 39. Convert to Black WhiteVersion 1

Technique #39. Convert to Black & WhiteVersion 1

Here we'll use a Channel Mixer adjustment layer to change a color image into a black-and-white (grayscale, in the world of Photoshop) image. First, we'll apply a generally-accepted rule of thumb for using Channel Mixer, then we'll experiment with the results.

key concepts:

adjustment layers

Here's the image I'll use in this technique.

Step One.	Click on the Create New Adjustment Layer icon at the bottom of the Layers palette, and from the pop-up menu, choose Channel Mixer. By default it will display the Red channel at 100% and the others at 0%. Turn on the Monochrome checkbox and start experimenting with the three Source Channels sliders. The rule of thumb that works well for many images is to aim to have the three numbers add up to roughly 100. You can experiment with a variety of combinations, but be careful to avoid blowing out any areas of the photo (unless you want that to happen). In this example, the settings for the three channels were quite different but still added up to around the 100 mark.
Step Two.	Okay, so there really isn't a Step Two, unless you consider clicking OK a step. At this point, the Channel Mixer is making the photo appear in black and white, but we're still in RGB mode. I would recommend saving your document as is (in RGB with the adjustment layer), then using Save As to create a copy, flattening the layers and changing the mode (to Grayscale) of the copy. That way, you still have the original with an adjustment layer that you can tweak at any time.

Variations

In this example, I added a Gradient Map adjustment layer (above the Channel Mixer adjustment layer), using a simple black-to-white gradient.

Variation 1: Black-to-white Gradient Map adjustment layer

Here I changed the blend mode of the Gradient Map adjustment layer to Luminosity.

Variation 2: Luminosity Gradient Map adjustment layer

This time I changed the blend mode of the Channel Mixer adjustment layer to Hue.

Variation 3: Hue Channel Mixer adjustment layer

In order to fade the effects of the two adjustment layers (to make the photo have a slight color tint), I selected both layers and, from the Layers palette's flyout menu, chose New Group from Layers. Then I lowered the Opacity of the Group (folder) in the resulting dialog to 75%.

Variation 4: Faded adjustment layers