Making water with soft edge in Gimp

[Vandy]

Hello, joão paulo.

This will be a quite useful tutorial for creating water in GIMP. Thank you for writing it and sharing it.


TO ALL:

I have created a PDF document of this tutorial and have attached it to this message.

Enjoy.

Regards,

Gary

[joão paulo]

Thanks for the PDF version and the words Vandy

[Ascension]

Thanks Vandy, our resident scribe. I always like to download something and work on it with the browser closed.

[RobA]

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):


-Rob A>

[joão paulo]

Thanks for the improvements and the very useful script rob.