A Unique Way to Convert Images to Black and White

Science tells us there are somewhere north of 13.1 billion ways to convert an image to black and white. It's time to add another method to your arsenal, but this one is pretty cool. Here's how to use Channel Calculations to convert a color image to black and white in Photoshop. 

So, what the heck are channel calculations anyway? They're pretty much what they sound like: you select a single channel from an image, do the same for another image (it could be the original image as in this video), Photoshop does some math on them (the same math it uses for blending modes), and out pops a new channel, selection, or image. Because a single channel is black and white, containing luminosity data for a single color, when you combine two channels into a single output channel, the result is again black and white, making it an interesting and efficient method for generating black and white images, as the above tutorial from PIXimperfect shows. It's a pleasingly tidy method, and the ability to cycle through blending modes and channel selections within the dialog box gives you a very quick library of resultant looks. Give it a try!

[via Shutterbug]

Log in or register to post comments


gabe s's picture

13 minutes to tell us how to do something in 30 seconds?

Exceedingly annoying

Stephen Hutchinson's picture

Well presented, and gave the basics in 30 seconds as promised for those like me who want to know how to do it first and then have an option to figure out why it works later. So no, "not 13 minutes to tell us how to do something in 30 seconds" but 13 minutes if you want a more detailed explanation and a few extra tips

Thanks for the tutorial. I'm going to try it.

Anonymous's picture

If you're going to make a post about image quality don't make us evaluate the images in a highly compressed YouTube video.

yanpekar's picture

Please, slow down. It might be a great idea to save people time by giving all the info in 30 sec, but it's really hard to listen and digest when you are speaking sooo fast. Was a bit confused re set expectation of "30 sec" since the video is for 13 min.

Michael Moon's picture

Am I the only one who feels like he would make a fortune narrating books?

Nick Rains's picture

Not at all unique as per the title, this method has been around since Photoshop 3 and pre-dates even layers. Almost all B+W conversions blend the three basic RGB channels in some form or fashion, that's why there are so many ways to do it. The only difference is the exact method and how intuitive it is for you. I don't see anyone discussing 4 channel conversions or better yet, Lee Varis's 10 channel workflow.

Very nice result.

The are many tools out there with stunning BW / Grayscale results.
I like techniques which combine some clever contrast with combination of channels.