Let's take a look at the rest of the formulas beginning with the one for the first inversion mode, Difference. Difference uses subtract. So we're subtracting the luminance levels of the active layer from those of the background layer and then we find the absolute value. So in other words, the result is always positive no matter what and that's why we end up getting an inversion result is because the numbers bounce back essentially. The composite luminance levels end up growing ever darker and then they bounce back and become brighter again. Exclusion, which is a very similar mode, it looks a lot like difference except it has lower saturation values, there is a lot of graze in the composite image.
It uses a completely different formula that's based on the screen formula. So we're taking A+B just as we do with screen and we're subtracting AxB which is that multiply, but then we're multiplying that multiply formula by 2 and that creates another kind of bounce back. So colors that are very different from each other become bright and colors that are very similar to each other become either gray or very dark. So the bright colors doubled back and again, we get an inversion effect.
Now these next two modes subtract and divide, they were introduced recently in Photoshop. However, they were actually already available inside the program, the variations on existing modes. So Subtract just goes ahead and subtracts A from B. That's it, but it turns that to be the same thing as inverting the active layer and applying the Linear Burn mode. And so as a result, it's very likely we'll get clipping. Divide goes ahead and divides the luminance levels on the active layer by those on the background and it's the same as inverting a layer and applying the Color Dodge mode.
So again, they're not unique modes, but they can be useful every so often, especially where masking is concerned. Then we've got the component modes; Hue, Saturation, Color, and Luminosity and they don't really have equations. They're just mixes of the various primary components that are going on between the active layer and the background layer. So in the case of Hue, we're keeping the Hue from the active layer and mixing it with the saturation and the luminance of the background layer. In the case of Saturation, we're keeping the saturation of the active layer and mixing it with the hue and the luminance of the background.
In the case of Color, we're keeping both the hue and the saturation of the active layer and mixing it with the luminance of the background. And in the case of Luminance, we do just the opposite. We mix the luminance of the active layer along with the hue and saturation of that background layer. And that's it, folks. That's how the underlying math works were blending is concerned inside Photoshop. It's a lot of stuff to know, I don't expect you to remember these formulas, but you can always come back to this document if you needed in the future and hopefully, knowing the mechanics of the mode will help you anticipate how they work as we employ the various blending options in future chapters.
Get unlimited access to all courses for just $25/month.Become a member
Access exercise files from a button right under the course name.
Search within course videos and transcripts, and jump right to the results.
Remove icons showing you already watched videos if you want to start over.
Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.