Topic awaiting preservation: Modes, Blending Modes, and Things (Page 1 of 1)

People really get on my nerves sometimes. But that's my own fault.

Okay, time to start fiddling and thinking.

Let's start with High Pass sharpening in RGB mode.
- Copy photograph
- Filter > Other > High Pass to taste
- Set blending mode to Linear Light and reduce Opacity to taste

Of course, Linear Light is going to be a bit heavy handed. This is because of the way LL works. But it's not the heavy handedness that bothers me - it's the cries of over saturation. "It's over saturated, so change blending mode to Overlay or Soft Light." Guess what? That will also affect saturation, and the point of changing the blending mode is to avoid messing with saturation at all.

Aaahhh! Go away!

The fix is to High Pass sharpen Luminosity only.
- Copy photograph
- Edit > Fill to extract Lum
- Copy this again
- set bottom one to Lum
- Clip the top one to the grey Lum layer
- High Pass and Linear Light, Overlay, or Soft Light the clipped layer

Ta-freaking-da. You just did some High Pass sharpening and left saturation *totally* alone. Was that so hard?

The basic idea: extract Lum, manipulate it, put it back in. If all you want to fix is Lum, then fix only Lum. Hello?

Doing this in Lab mode is a mite easier.
- photograph in Lab mode
- Copy
- High Pass
- Linear Light, Overlay, Soft Light
- Advanced Blending > turn off a and b

In this way, you don't have to worry about extracting. It's a more direct route or short cut. Turning off a and b is something that I use quite often in Lab mode. Same for turning off L and leaving a and b turned on.

We took something in RGB and mimiced it in Lab. What about mimicing other blending mode things across spaces? This is where things get interesting.

- start with a colourful photograph in RGB
- new layer and fill with pure black
- set blending mode to Multiply

Looking at the black abyss, eh? This is one of those simple RGB things that most of use are used to and sometimes take advantage of. Now for the interesting part.

- Image > Mode > Lab and don't flatten

Now what are you looking at? Not quite the same, is it?

The pure black has no affect on a and b because the black has no a and b, so to speak. And the fact that Photoshop doesn't exactly clamp saturation properly based on Lightness.

Ready for some more observations?

- turn off the pure black layer
- copy the original photograph and set to Multiply

Notice what happens to saturation. WTF? And I do mean WTF?

To see it better, maybe whip out Histogram and watch what happens to a and b while you turn the Multiply layer on and off.

Wanna see something really cool? Change the blending mode to Screen. Haha!

I don't think we are in Kansas anymore, Toto.

I have gone a few more steps, but I think that's enough for now.

We love LAB. Curves rock there.

Honestly haven't [played much with blend modes and such (yet) though. Thanks.

Very cool.

Okay, skip ahead skip ahead. Too many little things.

The next time you are in Lab and just messing around, try this Advanced Blending hack. At the very top of the layer stack, put a new layer and fill with any shade of grey you want. Set the blending mode of this top layer to Saturation. Open Advanced Blending and do something like this for the Lightness channel:



Non-destructive and tweakable. No more ChOps to get rid of blue shadows or pink clouds.

Colour me happy.

Great minds think alike, WJ, Mathias Vejerslev got a similar trick on the U2U, in the lounge>basement resources...

Pierre Courtejoie

(Edited by sPECtre on 01-23-2006 19:44)

I took me awhile, but I found it.

Haloless Sharpening

If it wasn't for you pointing these things out, Pierre, I would miss out on so many similiar things, tangents, and variations. Kudos to you for keeping my eyes open.