Black and White from Colour Images – Part 3 – Digital Photography Tip of the Week

Last week I continued my discussion of black and white digital photography and the topics of using grayscale and saturation to convert you colour photographs to black and white. This week I discuss using the channel mixer in order to create pleasing and dynamic monochrome photographs.

Channel mixer is available in the full version of Adobe Photoshop CS2, and a similiar tool is available in Microsoft Digital Image Suite. Adobe Photoshop Elements 4 does not offer such a tool, though I am sure there are third party plugins that will perform the same functions.

A digital photograph consists of three colour channels, red, green and blue. Each of those channels is a separate, monochrome image. Displaying each channel individually will show this (and also presents another method of converting to black and white, using only one colour channel). Using the channel mixer though, we can control just how much of each colour channel we use when creating our black and white images.

To open channel mixer in Adobe Photoshop CS2, click on Image => Adjust => Channel Mixer. Whenever possible, using adjustment layers is the best way to make corrections to your photograph as they can be re-edited later on. To make an adjustment layer for channel mixer, click on Layer => New Adjustment Layer => Channel Mixer. The dialog box you will see next has 4 sliders, one for each colour channel and one for constant. The next step after opening channel mixer is to click on the monochrome check box at the bottom of the dialog box.

You can now slide each of the sliders back and forth to increase the intensity of each channel. Results are best when the total of all three channels equal 100, though sometimes a little over or a little under will work as well. The constant slider is used to lighten or darken the whole image by a constant amount across each colour channel.


Original Image


Converted to Grayscale


Desaturated


Channel Mixer


Settings used for above Channel Mixer Image

As you can see by the examples, simple black and white conversions often lack punch and drama that black and white photography has been known for. Controlling each individual colour channel during the colour to black and white conversion allows you to make more dramatic black and white photographs from your colour images.

Next week, I will conclude my series on black and white photography by touching on a few other, less seldom used methods of converting to black and white.

The digital photography tip of the week is written by the PCIN Assistant Editor, Chris Empey. Chris is a long time photographer and is currently the President of the Niagara Falls Camera Club. You can see more of his photography at his Photo of the Day website. If you have a tip to send Chris, or a question about digital photography he can address in the newsletter, send it to chris@pcin.net.

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