After advising a fellow AS user to use GIMP, they asked me to help them. I promised a tutorial to be posted in the forums, so, here it is. I make no claim to be an expert in the matter. I'm just providing what was requested. In this tutorial, I will share my method for giving characters scars and gashes. Feel free to recommend other techniques if they can be applied to this topic.
For this tutorial, I will beat up on my character, Kuva.
Start with your character. While you can use my method on any image, it's best if you make your image's layers follow a pattern similar to mine. Base to top layer, you should have your picture organized thus: Background, Lineart, Color, Other layers for shading and lighting and textures, Lineart Copy. Other layers are up to the artist.
Next, make a duplicate of the Color layer. Name it something like "Color/Scarring". It's always good practice to modify a duplicate of your base image, that way you don't start pulling your hair out because you permanently modified the original lossless file of your masterpiece. You should do all your scarring on this duplicate layer.
Now we're ready to beat up on Kuva. First we're going to make the old, healed scar. For that, we need a flesh tone. Something you would find if you parted the hair of a dog to see the skin beneath. Lacerations heal differently than abrasions, especially deep ones. Usually a scar heals a lighter color than the skin surrounding it. However, as an artist, you also want to take perception into consideration. I chose a slightly darker flesh tone than I would normally choose because of how dark Ivan's fur is. The contrast made the scar appear much lighter.
Next, you will want to select the paintbrush tool, along with the feathered brush.
Now we're ready to put in the scar. Using the tools we've selected, apply the flesh tone wherever you want scarring to appear.
We now have a pretty convincing scar, but this is a bit over simplistic. Hair doesn't grow in scar tissue, but it will still grow around it. We want to show that the scar has been there a while by painting some fur around it. For this task, use the eyedropper to select the color of the fur around the scar. Next, choose the smallest brush possible for the paintbrush tool, and set it to fade out. The fading distance needed will depend on the resolution of your image. The greater the resolution, the longer the fade distance should be. When zoomed in, it should become apparent that this brush only covers one pixel. Be sure to use the paintbrush tool; all the pencil will do is make blocky, jagged lines that are simply ugly and unconvincing.
Let's start with the ear. Using the properly prepared paintbrush tool, apply lines to indicate fur on the edges of the scar. This can take some practice, especially with a mouse, but it's not difficult to master. The fading effect should indicate the length of the fur surrounding the scar, and some trial and error may be involved to get it just right.
Next, work on the scar over the eye. The same steps apply: eyedropper, pinpoint brush, fade out, indicate hair.
Remember to use the eyedropper for the fur surrounding the scar. Even a slight color variation is going to look funky. Depending on the type of scar you want, it may show more or less on the eyebrow than elsewhere. In real life, I have seen more skin show through an eyebrow, but I wanted my character's eyebrows to appear extra bushy.
That's how I do old scars.
On to fresh scars and lacerations...
This is going to work very similarly to making an old scar, but with a little extra work. First let's choose the color for the blood. We all know blood is red, but just pulling red off the default palette won't work. When exposed to air, blood instantly begins to oxidize, and turns a very dull red. We want to imitate that, so you may start with whatever red you want, but you should darken it in the color mixer.
Once you have chosen an appropriate color, apply the color the same way you applied the flesh tone for the old scar.
You may also choose to add blood running down away from the actual cut itself. I recommend using a smaller feather brush for this job.
Let's also add a painful looking gash to Kuva's chest. It will allow me to show you something else later on.
Let's return to the cuts on Kuva's muzzle. Remember what we did for the old scar? Do the same thing; use the eyedropper to get the local color of the fur, then draw fur around the edges of the cut.
Do the same for the gash on his chest, but only on the dark fur for now.
If you've ever been fortunate enough to go hunting, and of a solid enough constitution to gut the kill yourself afterward, you will notice that blood causes fur to clump together and stick out. I attempt to imitate this phenomenon in my own work by taking the blood color and applying it in the same manner as the fur to the side of each cut that is supposed to be farthest away. For instance, in my image, Kuva is quartering toward the viewer, facing to the right. That means that in two-dimensional space, the furthest side of each cut we are concerned with will be on the left.
The same applies to the gash on the chest.
Let's focus on that gash now. We've already covered what to do for cuts on dark fur, and it's esentially the same for light colored fur. You know the drill...
Your lighter colored fur should look something like this when you're done.
Now, remember; blood is a liquid, and like all liquids, has a tendency to soak into nearby fibers. With dark colors, this isn't so visible, or important, but because we have a cut that crosses into nearly white fur, we're going to add the soaking effect around every cut. We're going to add a gentle halo of red around each cut with the spray-paint tool and the feathered brush.
Before we tackle the white, we should drop the rate on the spray-paint tool down to fifty. This is because any red we add will show very easily on such a light background. Carefully apply the color around the cut, growing lighter and lighter the farther away from the cut you get, until you feel you can't apply any lighter hues to the edge. This is the part where a pressure sensitive tablet is extremely handy, but if you are using a mouse, just drop the rate down even further, and if you apply too much, remember that GIMP has a very long "undo memory."
Now we have a pretty roughed up Kuva.
Now that you've read my tutorial, Kuva needs a rest. NO! You can't use him to practice on! Beat up on your own character!
