Digital Black and White

Many digital cameras have a setting to shoot in black and white. Some cameras do a direct conversion, others show what it would look like in black and white and then have the user do the conversion in Photoshop instead. The advantage of the latter is that the image quality is higher when the conversion is done in Photoshop instead of in the camera.

To convert an image to black and white start with the channel mixer

Image>Adjustments>Channel Mixer

or Layer>New Adjustment Layer> Channel Mixer

Channel Mixer

Set the check box to monochrome.

Try 60 Red - 30 Green - 10 Blue.

The sum total of the three should always be 100%


Colors that contain very little red appear dark. The red channel is like a deep red filter. The Constant slider adjusts the values of the output. Going left makes it blacker. Each of the channel sliders has a 200% range.

Source: p. 32 + 33 Mastering Black and White Digital Photography – Michael Freeman 2006

Using Channel Mixer and Adjustment Layers

Source: p. 40 + 41 Mastering Black and White Digital Photography – Michael Freeman 2006