View Full Version : Making water with soft edge in Gimp
03-29-2009, 07:36 PM
The first step is open GIMP and create a new image,with the brush tool, paint a blue patch that will serve as the basis for our tutorial.
03-29-2009, 07:45 PM
Now we have this body of water, we can begin the work.
In the menu "filters" select "blur">"gaussian blur" the level it in this case is 70 pixels.
03-29-2009, 07:49 PM
Use the menu "Colors"> "posterize" changed for 10 levels.
03-29-2009, 07:53 PM
In the same menu "Colors"> "brightness-contrast" changed to 6 and 23 respectively.
03-29-2009, 07:56 PM
Again use the "gaussian blur" filter this time for 12 pixels.
03-29-2009, 07:59 PM
In the "layers window" create a new layer and add an "alpha channel" to it.
03-29-2009, 08:05 PM
Paint or load a terrain to this new layer.
Now using the "eraser tool", erase the region over the water(in the new layer).
03-29-2009, 08:09 PM
The end result of our work should be more or less like this:
Please feel welcome to correct any errors I have committed on this tutorial.
03-30-2009, 12:32 AM
That's a nice looking water.
03-30-2009, 08:26 AM
Lookin' good JP!
03-30-2009, 09:58 AM
Hello, joćo paulo.
This will be a quite useful tutorial for creating water in GIMP. Thank you for writing it and sharing it.
I have created a PDF document of this tutorial and have attached it to this message.
03-30-2009, 10:10 AM
Thanks for the PDF version and the words Vandy :)
03-30-2009, 06:28 PM
Thanks Vandy, our resident scribe. I always like to download something and work on it with the browser closed.
One suggestion on the posterization technique.
Gimp's posterize "is designed to intelligently weigh the pixel colors of the selection or active layer and reduce the number of colors while maintaining a semblance of the original image characteristics" (from the gimp docs).
What is not explicitly mentioned is that each channel of the image is separately analyzed. This means for a posterize setting of 3, you will end up with 3 levels each of R, G, and B, or 27 colours.
This works nicely for some images:
But not so well for single colour gradients (like the blur in this tutorial creates) that are not pure R, G, or B
I found a tutorial on the web that described using an index mode conversion to create a different posterized version of an image. Attached is a script that implements this (Shows up under colours->Posterize Indexed...). Note that the slider here is the number of colours, not channel levels, so a comparable setting to posterize level 3 would be 27 colours.
Here is a typical gradient, posterized and with my posterize indexed script:
But it really depends on the source image, as this might not be what you expect from the colourwheel using poster indexed (to 27 colours):
03-31-2009, 07:42 PM
Thanks for the improvements and the very useful script rob.
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