How do I do a realistic color change on a realistic fractal map ?

[Freodin]

How about that?



Very quickly done... but is that about what you want?

[johnvanvliet]

i guess i was assuming that you were using a "feather" of the edge
or
a fuzzy brush as an eraser on the top layer

1) circle select
2) 150 PX "feather"
3) bucket fill



also if the sand color is on the layer UNDER the green
you can use the eraser set at ? 20% and selectively remove some of the top layer

[Deadshade]

How about that?



Very quickly done... but is that about what you want?

Yes that's about the idea. I would make the transition band much wider so that one can't really tell where the green stops and the yellow starts but that could be probably done.
How did you do that ?

[Deadshade]

also if the sand color is on the layer UNDER the green
you can use the eraser set at ? 20% and selectively remove some of the top layer

No I didn't try that.
But I think I see what you mean. Having
1) B&W texture
2)Green
3) Yellow

I could try to remove some green from the green layer so that some yellow shows through from below. Problem being of course that this "removing" should be done in a very irregular way so that one doesn't see obvious traces of the eraser.
Generally the problem I get when there are several layers is that everything gets too dark.

[Freodin]

Yes that's about the idea. I would make the transition band much wider so that one can't really tell where the green stops and the yellow starts but that could be probably done.

If you make the transition zone too wide, it looks rather weird... you have to play with the settings a litte.

How did you do that ?

Most simple. Two layers. One green, with some texture added. Above it, a yellowish layer, with some texture added. On the yellow layer, add a layer mask, coloured black. Switch to "Show Layer Mask" to be able to paint on it directly. (It's in the layers context menu)

Use a white brush and paint where the "desert" should be shown. Apply a largish gaussian blur (I think I used 100px for this example)... that's where you define how large the transition zone is.

Unselect "show layer mask"... and you should be done.

[Deadshade]

OK, thanks. My Gimp knowledge is not sufficient to currently use masks and to know what I am doing. Never used "show layer mask" sofar. I will try to see what I can do with that method.
It is not eaxctly what I imagine but much better than an ugly sharp boundary.
At worst I'll learn something new about GIMP

[Chick]

There are two things that I do about this problem.

1. I try to put something on the boundary that breaks it naturally, such as forest, river, mountain range, etc.

If I can't do that,

2. I make two layers of the two colors, then use a soft (0 hardness) brush to erase the overlap areas until they kinda fade together. This lets you add or subtract color with soft brushes until you get the look you want, then merge the layers together.

[johnvanvliet]

all this comes back around to skills learned in colorizing B&W images like this one

http://tutorialgeek.blogspot.com/201...otos-from.html

think of the tutorials as the end of chapter exercises in your textbooks from primary and secondary school

[ChickPea]

My skills aren't that great, but for what it's worth, I use Selection / Feather tool a lot when I want to blend. It can't be used in every scenario, but works great when you want to remove the edge from a block of colour.

[Deadshade]

all this comes back around to skills learned in colorizing B&W images like this one

http://tutorialgeek.blogspot.com/201...otos-from.html

Thanks but I know how to color B&W images, that's easy. In this tutorial everything is just plain sharp boundary. My problem is opposite - I need to get rid of sharp boundaries and get a color difusion pattern.