How to Use Photoshop’s Divide Blend Mode and a Free Math Lesson That Will Blow Your Mind

Given Photoshop’s complexity, it can be incredibly refreshing when someone comes along and explains not only how a certain tool works but also how to use it. This fantastic video from PiXimperfect runs you through how to use the Divide blend mode in Photoshop and packs in a free math lesson which will help you to understand why it does what it does.

Unmesh Dinda is widely revered as the definitive authority when it comes to learning Photoshop, and this short tutorial is no exception. It would never have occurred to me to use the Divide blend mode when attempting to remove a color cast from an image, largely because I had absolutely no idea what it did or what it was for. Dinda unpacks it, casually walking you through how to use it and why it works, throwing in a free math lesson along the way. If you left high school wondering when you’d ever need to use algebra, make sure to watch to the end.

Dinda finishes with a challenge: right now, lots of us are spending our time upgrading our Photoshop skills, and he wants you to find another use for this blend mode. What are your ideas? Leave a comment below.

Andy Day's picture

Andy Day is a British photographer and writer living in France. He began photographing parkour in 2003 and has been doing weird things in the city and elsewhere ever since. He's addicted to climbing and owns a fairly useless dog. He has an MA in Sociology & Photography which often makes him ponder what all of this really means.

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14 Comments

Love learning something new all the time. The colorcast fix seems so simple, yet I've been doing it in lightroom and never seemed to get it right. Now PS is more useful, thanks for your help!

I hate to nitpick about an otherwise excellent presentation, but the 256 in his formula really should be 255 (the full-scale value for the channel). Try this example in PS: fill top layer with white (255,255,255), fill the layer beneath it with (254,254,254), apply Divide blend mode to the top layer, and measure the result on the Info panel. You'll see (254,254,254).

256 / (255/254) = 254.996, rounds to 255 (Formula in the video)
255 / (255/254) = 254 (Corrected formula)

Again, that doesn't take away from the useful technique presented.

So is this how the white balanced adjustment tool works in Camera Raw?

Unmesh's videos are so informative. Thank you for sharing ❤️

Other use: Use this technique to correct an incorrectly set white balance camera setting without going into the camera raw filter.

Even then you could adjust the white balance in the Camera Raw Filter.

I had the same question though. Perhaps there are better uses of that blend mode.

I agree better to handle it in RAW, but I can see a unique use for this method: a scan of an old photo, where because of the deterioration the color cast is uneven. For that you could use a gradient as a color fill layer and neutralize the cast differently across the image.

Thank you for this great informative tutorial!

Good videos from him, really, just hate, that the advanced videos includes all the basic beginners thing again and again...tired to watch... so long like this. In every video he wants to tell everything again. If somebody is a beginner, watch beginner level....

:-)))))

Leave it to Unmesh to figure this stuff out and then teach the rest of us. Who would have thought?

Now we just need to figure out how to AUTOMATE this! Right?