HOWTO draw realistic hair or fur in Gimp; or "follow a Photoshop tutorial using Gimp instead".
The other day while skipping through the daisies on Digg, I chanced 'pon a nifty little Photoshop tutorial about making a beard on a face shot. "Cool beans!", I exclaimed dorkily, admiring the realisticly hairy effect producing a caveman shag on the guy in the picture, "I think I'll give it a shot." So I did:
Now, let's assume that you already clicked the above Photoshop link like good little boys and girls and are familiar with how it goes. Now here's the "diffs", if you will, on how to do it in Gimp:
Done in Gimp 2.2.10 - and no Wacom tablet.
I started by drawing the brush much as the tutorial describes, using a paintbrush with fuzzy circle 05 at fade-out 45 and the curved lines tool, creating paths which I stroked with the brush.
The next part was a challenge; Gimp has no equivalent of shape dynamics for brushes. So I simply duplicated layers to the brush and flipped and rotated it and skewed, creating an image pipe type of brush instead. In place of having the image program randomly manipulate the brush characteristics, I could define my own one frame at a time. The image pipe dialog - activated automatically whenever you save a file with the extension ".gih", gave me options to set the image pipe similar to PS's brush shape dynamics. I picked random for all layers and saved it to my brush folder.
(very old) Tutorial on image pipes here:
I experimented a few times to try different effects. While I couldn't do color dynamics, I could substitute by setting the brush opacity to 40-60%, and playing with the fade-out and pressure sensitivity for different thicknesses.
Finally I got down to it. True to what the tutorial said, you just draw the hair on! I filled in the large black area normal, then set the fade on and made short strokes all around the border to bush it out. I even used another animated brush, "confetti", to add in stubble around the border of the beard on his face. Here he is now, with apologies to Abe Lincoln:
Making it blend in with his natural hair would be an exercise in futility. I know I picked a bad subject, but Dick Cheney was the only public figure I could think of without a beard who would have a suitably high-resolution photo to work with that I could find with a reasonable amount of Googling. Still, I resolved to try some color-blending anyway.
I settled on using a lighter shade of gray with the brush at a higher opacity and the topmost layer set to "overlay". I did this because doing it the way the tutorial said made it look smeary.
After applying some frost highlighting (sloppily), I had something as close to what I could call passable. Flatten the layers, and save it original size and one-quarter to post here (and hide my errors, heh, heh).
I posted my result to the forum where the comments on the tutorial were and twiddled my thumbs. Alas, after 24-hours of twiddling, I have failed to garner a single congratulatory comment; I was probably too obvious about trolling. However, it got a few clicks and glances and one humorous comment, and nobody has stood up and screamed, "FRAUD! You did this in Gimp, you impostor!" So, as the saying goes, no news is good news.
It still bothered me that the white hair and black beard didn't match.
So I added a turban.
This was fun. I think I'll make a point of passing off Gimp work as Photoshop work in the future, just to see how far I can get.
NOTE: No disrespect to the Vice President; I picked him out of the blue. Rest assured that I am completely non-partisan: I dislike all politicians equally.
UPDATE: And if you think this is cool, check out this Italian forum where somebody made adorable plush toys, apparently with a similar technique in Gimp.
By the way, I didn't think to try using a gradient for a fill color on the pipe brush at the time. If anybody else has a similar demo they'd like to share, please post a link in the comments.