grain extract and grain merge

[gimp-artist]

Hello guys, how are you doing? I'm reading gimp Docs. Here is what they say about "grain extract" in layer modes.

Grain extract mode is supposed to extract the "film grain" from a layer to produce a new layer that is pure grain, but it can also be useful for giving images an embossed appearance.

I don't think grain extract gives images an embossed appearance, but grain merge gives the embossed appearance.

What do you think about it?

[Espermaschine]

It does when you duplicate an image, set the upper layer to 'Grain Extract' and offset a few pixels.

Fun fact: Photoshop doesnt have a Grain Extract Blendmode, but an Emboss flter which does exactly this.
Gimp FTW !

[gimp-artist]

(05-03-2018, 11:09 AM)Espermaschine Wrote: It does when you duplicate an image, set the upper layer to 'Grain Extract' and offset a few pixels.

Fun fact: Photoshop doesnt have a Grain Extract Blendmode, but an Emboss flter which does exactly this.
Gimp FTW !

----------------------------------------------

Thanks. If I haven't read your reply I won't able to find out what the grain extract and merge are for. At first, I doubt about the offset you wrote. After I moved a few pixels, boom, it's new world, really. Thanks. Have a nice day

[Espermaschine]

There are a few tricks you can do with blendmodes.

The obvious one is: when you have lineart made of black lines on a white background, you can make the white invisible by setting the mode to 'Multiply'.
The reverse (white lines on a black BG) is true for 'Screen'.

My favorite "trick" is using a black layer on top set to 'Saturation' to make an image look greyscale in a non-destructive way.
The real benefit however is, that contrast is easier to judge when an image has no colour.
So whenever im not happy with an image, but dont know exactly why, i use this trick to adjust my colours and make everything "pop".

[gimp-artist]

Thanks for the very practical answer. I knew what I have read about modes in gimp Docs, but I did not know what the all the modes are for. Your answer gives me a lot of possibilities. I feel like I leveled up. Thanks mate. 

[Espermaschine]

(05-05-2018, 07:06 AM)gimp-artist Wrote: Thanks for the very practical answer. I knew what I have read about modes in gimp Docs, but I did not know what the all the modes are for. Your answer gives me a lot of possibilities. I feel like I leveled up. Thanks mate. 

Yeah, learning to understand blendmodes takes a bit of an odyssey.
I did the same as you, reading the descriptions in the Gimp manual, and although the developers did a great job of writing that up for us, its still a little dry.

Another good tip to remember is: 'Hard Light' is 'Screen' and 'Multiply' combined into one layermode.
So lets say you bumpmapped text into a 50% gray layer, which gives you a 3D look with shadows (black) and highlight (white).
When you set this layer to 'Hard Light', the grey will become invisible but the shadow and highlight will remain.