LAB Overlay Technique

[macaddict]

Image mode changed to Lab Color, then Image>Apply Image. Change blend mode to Overlay. Change channel to B. This is at 100% opacity:


Change channel to A. This is at 100% opacity:


Change channel to Lab. This is at 100% opacity:


Original image:


The best punch, in my opinion, is B. So, I lowered the Overlay to 30% opacity and here's the final image:


That's all there is to it - a quick and easy punch.

I will say, I'm now reading Chapter 3 of Margulis's Photoshop LAB Color - I'm amazed at the results using his techniques!

[bham]

Thanks for doing that. I have tried about everything to get the exact match on the first two pics and couldn't and still can't but could on the second example. I was doing the right thing but for some reason the images don't end up same.

Thanks again. Great technique.

[jfriend]

Originally Posted by macaddict

Image mode changed to Lab Color, then Image>Apply Image. Change blend mode to Overlay. Change channel to B. This is at 100% opacity:


Change channel to A. This is at 100% opacity:


Change channel to Lab. This is at 100% opacity:


Original image:


The best punch, in my opinion, is B. So, I lowered the Overlay to 30% opacity and here's the final image:


That's all there is to it - a quick and easy punch.

I will say, I'm now reading Chapter 3 of Margulis's Photoshop LAB Color - I'm amazed at the results using his techniques!

OK, this is fairly easy to understand. There must have been some other significant things you did to the original image you started this thread with because a strict overlay doesn't produce the result you ended up with. No worry.

Anyway, overlaying a LAB color channel with itself is very much like steepening the curves on the same LAB channel in chapter 1 of Margulis' book. If the image doesn't have any brilliant colors (which is true of most images), then it's nearly identical.

For reference, Rutt posted here how you can get the exact same result as Apply Image/overlay with a curve (it's just a large S-curve that does the same thing as the overlay blend mode).

I, myself, prefer using the curve over Apply Image because it's 200% more flexible. Just switch to LAB, create a curve adjustment layer, switch to the A or B channel and steepen the curves. You can either push in the ends (a la chapter 1 in Margulis' book or you can make a big S-curve that approximates the overlay mode (see Rutt's posting referenced above).

I prefer this way because not only can you vary the steepness of the curve and the opacity to control how much of an effect you get, but it goes in an adjustment layer so you can easily turn it on/off to gauge the effect and even dial it back after-the-fact. Further, you have the abilty to manipulate the shape of the curve which can apply more of a change to some colors than others and you can use the BlendIf settings to dial-back the effect from brilliant colors if you need to exclude them. And, lastly, you can also adjust any color cast with the curve if any appear when you enhance the colors (which happens to me about 1/3 of the time).

So, feel free to use Apply Image/Overlay if you want, but I think it gives you a lot more control and flexibility to use a curve adjustment layer. Thanks for sharing.