How to Convert Photos to Black and White with the Channel Mixer in Photoshop



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How to Convert Photos to Black and White with the Channel Mixer in Photoshop

This article is part of our series Photo Editing 101 by Ian Pullen. This series will cover all of the basics of using Photoshop for editing photos. If you’re just getting started with Photoshop or photo editing, or if you’re looking to improve your skills in this area, this series will provide an excellent foundation. If you want to make sure that you don’t miss future articles you can subscribe to our newsletter or follow us on Twitter, Google+, or Facebook. You can also find the articles that have already been published by visiting the Photo Editing 101 course page.

The Channel Mixer in Photoshop makes it possible to convert images to black and white with a degree of control that is not possible by just desaturating a photo or converting it to grayscale. Both of those techniques are one click methods that see the same conversion applied to every image.

What may work well on some photos could be less effective on others. Your photos are the result of your camera recording red, green and blue light and the Channel Mixer gives you the ability to adjust each of these color channels individually when making a mono conversion.

This gives you the capability of adjusting the tonal value of skies, foliage and other objects to dramatically vary the appearance of a mono conversion. In the rest of this article, I’ll introduce you to using the Channel Mixer to convert your photos to black and white, using the presets and making your own manual adjustments.

How Do You Open the Channel Mixer

How to Convert Photos to Black and White with the Channel Mixer in Photoshop

To open the Channel Mixer, just go to Layer > New Adjustment Layer > Channel Mixer or, if the Adjustments palette is open, just click the Channel Mixer icon, which is at the far right of the second row of icons in the main menu.

How Do You Convert a Photo to Black and White?

How to Convert Photos to Black and White with the Channel Mixer in Photoshop

Converting your color photo to black and white is as simple as clicking the Monochrome check box. You’ll see that by default, the red and green channels are set to 40% each and the blue channel is set to 20%. If you look just below the Blue slider, you’ll see the Total shows +100%. To keep the overall exposure of your image the same, whenever the individual sliders are adjusted, they should always add up to 100%. If the total is lower, the image will start to become darker and a higher total will lead to a lighter image. In both cases, there will a little warning icon displayed by the Total. Obviously you can ignore the warning and in some cases you may choose to lighten or darken the image a little using the Channel Mixer. However, for anything but very minor tweaks, there are other tools better suited to this task.

How Do You Use the Presets in the Channel Mixer?

The Channel Mixer’s presets are the easiest way to make adjustments when converting to black and white and these are designed to replicate traditional lens filters used in black and white film photography.

To use one of the presets, just click on the drop down menu at the top of the palette and select one of the options there. I’ve included screen shots of the effect of the blue, green and red filter presets here to show how they can produce dramatically different results.

How to Convert Photos to Black and White with the Channel Mixer in Photoshop

The above photo is the Black and White with Blue Filter which gives quite a neutral appearance to this landscape scene.

How to Convert Photos to Black and White with the Channel Mixer in Photoshop

The above photo with the Green Filter has increased the contrast a little more making for a more interesting exposure.

How to Convert Photos to Black and White with the Channel Mixer in Photoshop

The above photo with the Red Filter has further increased the contrast across the frame and has produced an image with more depth than either of the other two. However, results with filters will vary depending on the subject, so it always makes sense to try out all of the filters to see which provides the most pleasing results. With photos containing a lot of foliage, the Black and White with Infrared Filter can give very interesting results, with leaves turned to near white.

How Do You Manually Set the Channel Mixer?

How to Convert Photos to Black and White with the Channel Mixer in Photoshop

You can also adjust the sliders manually and this can be a way to tweak a preset to produce a more dramatic effect. If you do this, remember that the Total should ideally always equal +100%.

In the above screen shot, you can see that I’ve increased the red and decreased the blue quite significantly.  This has turned part of the sky nearly black and lightened the fields dramatically, however, you may note that the gradation in the sky has become a bit coarse as a result. Do take care not to push the settings too far.

How Do You Use the Constant Slider?

How to Convert Photos to Black and White with the Channel Mixer in Photoshop

The Constant slider can be used to adjust the lightness or darkness of the image, though I’d advise that you only ever use this for minor adjustments. There are other Adjustment Layers available that are far better suited for making such tonal changes to a photo.

Conclusion

The Channel Mixer gives you the flexibility to convert color photos to black and white with far more control than just converting the mode to Grayscale. However, in versions of Photoshop that include Black and White Adjustment Layers, that is a feature that offers even greater control.

See more articles in the Photo Editing 101 series.