Gradient Map/Reverse Gradient Map Script

[virtualTune]

well...they all utilise GM and i thank you for linking them,. but they don't explain what they do and what one would have to do to get the desired change. Say Blue to green. I don't know what will happen!

[bladesonic]

If you want to find out what they do, try it. Just experiment with them.

[fencepost]

The link to the GIMP manual explains exactly what it does. But, I agree with bladesonic: experimentation is the key. The worst thing that can happen is that you'll have to use the Undo command. Well, that's not the worst thing that can happen, but you get the idea.

[virtualTune]

yeah i did play around, accidentally hit save....that was the worst that could happen! I should try again on a less important piece!

[virtualTune]

ok here we go:

Spoiler: show

Chucks_of_my_grandma_by_fogke.jpg

before

Spoiler: show

GM.png

after


So you have to duplicate the current layer it is applied to. set it to EG overlay and play with opacity. When I tried it before I always made a new transparent layer. that way nothing showed up however! thx guys.

@maffe, I'll be glad to help you!

ignore the render it sucks!

[fencepost]

Glad you were able to get some results!

So you have to duplicate the current layer it is applied to. set it to EG overlay and play with opacity.

Not necessarily. You can apply a gradient map directly to the active layer OR, if you're using my gradient map script, apply it directly to all layers in the image. However, it appears that the tutorials I provided links to always apply the gradient mapping to duplicate layers and adjust opacity. It really depends on what effect you're trying to achieve.

When I tried it before I always made a new transparent layer. that way nothing showed up however! thx guys.

Correct. In order for the mapping to take place, you have to have something other than transparency to work with. I think people get the impression that gradient mapping is a similar thing as adding a gradient to a layer. However, the only way they are similar is that they both use gradients. You can add a gradient to any layer (transparent or filled) and set the opacity, blend mode, gradient shape, etc. However, the gradient mapping simply exchanges existing colors within a layer using the chosen gradient. There are no options to set opacity, blend mode, shape, etc. because color 'A' in the gradient is exchanged with color 'A' in the layer. Unfortunately, you can't specify which color in the gradient should replace the color in the layer. However, I believe there are other techniques in GIMP to accomplish that, but that's not something I'm an expert in.

Don't know if this helps or not, but it looks like you're on the right path.

Art

[virtualTune]

now, i figured i would get the same results if i just make a new layer. add the desired gradient. set mode to overlay and play with opacity. so there is no need to make the gradient mapping.

[fencepost]

No, they are not the same thing. Try it and see. Gradient mapping is a color exchange and adding a gradient & changing the blend mode/opacity is just overlaying with a gradient. I've used your signature as an example.

Incandescent gradient placed on a new layer (linear shape, Overlay mode, 100% opacity)



Incandescent gradient map

[David Wood]

That's right, adding a gradient to a layer isn't gradient mapping.

In gimp, when gradient mapping, the foreground color will be the dark colors in the image, and the background color is going to be the light areas.

[virtualTune]

though the same effect could be achieved with gradients..?!

that was a good example fencepost! thank you. you should make some tuts. u're really good att explaining stuff!

[David Wood]

I'm working on one.

[virtualTune]

IMO (!!!!!) fencepost is easier to understand though.....

[fencepost]

though the same effect could be achieved with gradients..?!

Probably not easily. Remember, you're exchanging one color for another. With a gradient overlay whatever color is above the layer is just blending with the layer below. Exchanging does NOT equal blending.

should make some tuts. u're really good att explaining stuff!

I've written a few in my day.....http://fence-post.deviantart.com/galler ... -Tutorials

Art

[fencepost]

IMO (!!!!!) fencepost is easier to understand though.....

I think David will do a good job. Don't be too hard on him. I don't write many tutorials these days....my joy is scripting.

[virtualTune]

i am hard on him cuz he behaves like my big bro(which is fine cuz i have no sibblings)