HOWTO applly merge technique

[graemev]

I came across this technique in PS  https://www.youtube.com/watch?v=cv7YP5L-2Zs


In essence it depends on being able to merge pixels from the layer below based on the brightness of the pixel in THIS layer (or the one below)

... hard to explain, the video does it better.

It seems to produce some good effects, I'm struggling with a achieving the same effect in GIMP.

...my best guesses are something like making a mask based on the "level" of one of the images, but this fails to encompass the "gradation" concept

[trandoductin]

Not sure of exact method, but maybe this will help.
On a new layer, I chose color of sky, darken it turned up saturation a bit and changed the hue of color and painted the whole sky
Then I used the original layer and pasted that as a layer mask for the new layer and invert the layer mask.
Then you can play with curves on the mask. (I like to use the S-Curve)

[rich2005]

Nothing like that in Gimp, that is a PS layer style. Gimp is much more hands on.

Give the guy in the video credit, he did try and explain how it worked and looked to me like it is a clever use of on-the-fly layer masks.

The best I can come up in Gimp is use of luminosity masks, https://patdavid.net/2013/11/getting-aro...masks.html not exactly the same as PS but you might a result.

Remember that tutorial images are usually set up to accentuate the effect and that one is no different. Had to hunt around for photo with clouds but then using duplicated layers in different modes (experiment with that) and used the levels tool on each layer.

Original looks like this: https://i.imgur.com/1Lw2rzJ.jpg

Enhanced clouds like this: https://i.imgur.com/kK1ABLI.jpg

[graemev]

trandoductin, yep I've used that and similar techniques in the past (usually using a raw processed at different settings) The technique in that video is "different" so instead of "me" saying , take the top bit from this image and the bottom bit from that , the actual image makes the decision. I did come across a "trick" used in this technique (for a different purpose) http://www.cambridgeincolour.com/forums/thread3924.htm. Which feels like it might have some promise ...make a layer mask using the image then play with colour levels (on the mask) to get the setting I want.

(feels like the same/right sort of thing as the image creates the mask and the "picture" (being masked) is/can be just painted on dabs of colour)

rich2005 , I'll take a look at that plugin, thanks.

---

Dug out somewhere I did the earlier technique a while back.

Before: https://photos.app.goo.gl/TahMGd0flG8xkro02
After: https://photos.app.goo.gl/jTylU9sQibHoad8F2

[graemev]

Read up the tutorial ( luminosity masks, https://patdavid.net/2013/11/getting-aro...masks.html ) sort of made sense. Then I installed the (faster version of) the plugin , launched it a few times, but no layers appeared . Finally RTFM the short description ... channels . It seems it makes channels not layers/layer masks!

I''ve not really used channels . My guess is I do channel to selection , then make a mask for a given layer from the selection?

[Ofnuts]

(09-18-2017, 02:54 PM)graemev Wrote: Read up the tutorial ( luminosity masks, https://patdavid.net/2013/11/getting-aro...masks.html   ) sort of made sense. Then I installed the (faster version of) the plugin , launched it a few times, but no layers appeared . Finally RTFM the short description ... channels . It seems it makes channels not layers/layer masks!

I''ve not really used channels . My guess is I do channel to selection , then make a mask for a given layer from the selection?

When you add a mask to a layer, you can initialize it from a channel: see the "Channel" button at bottom of the list, and the selector below, that contains the current channels, except the 5 implicit ones: R,G,B,A and selection.

The difference between channels and layers, beyond channels being just grayscale, is that channels always encompass the whole canvas.