I have found The GIMP to be a very powerful colouring tool, in fact I’ve found it to excel in this area compared to the likes of Adobe Photoshop, but I can’t say for Painter or openCanvas. That may be personal preference, but after this tutorial you can decide for yourself.

Firstly, this is not my lineart, since mine are much too sketchy to be used for CGing; it’s from Neon Dragon Art.

Open your image you want coloured. Then do this: (Remember right-click navigation is your friend!) Layer -> Transparency -> Add Alpha Channel (You know it worked because the “Background” layer will go from bold text to normal text). Now create a new layer, by Layer -> New Layer, then make it look like this. Hit OK. The new layer will appear on top of your drawing, but never fear! In the layers box (if you haven’t opened it, or don’t know how, Dialogs -> Layers), drag the new layer below the drawing.

In the layers box, select the drawing by simply clicking on it. Now set the mode to Multiply as seen in the image to the right. This allows you to colour without worrying to stay in the lines.

More than likely, your drawing will have an off-white appearance to it. Don’t panic, this is fixable. Go to Tools -> Color Tools -> Brightness-Contrast, then give it Brightness: +49, Contrast: +50. Hit OK. NOTE: If you’re using a different drawing, adjust the levels to you liking as is these would probably not work out well for you.

Now, make another layer between the background and your drawing; name it “Dragon” (or something for the base colours, in this case I just used “Dragon”). Take the brush tool and choose the largest fuzzy brush size. Start colouring in the drawing!

Your drawing should now have one layer of colour. But please! don’t stop there. Find the colour picker and click on the dragons skin. All of that colour — and that colour only, should be highlighted. This allows you to do the following step without worrying about getting outside the lines.

Create a new layer, this time on top of your base colour, and name it something like “Shadows 1″ because if you want to get into high detail… you’ll want more than one shadows layer. ;) Set the mode to Multiply.

Here is when smaller fuzzy brushes are perfect, so use those and fill in according to wherever you desire the lightsource to come from.

Everything from now on is basically this, but I can’t teach you to be an artist — only techniques. So I’ll write a Part II later for good techniques in CGing. The finished product is seen on the right — no background, but I did it for this tutorial… ;)

The Full CGed Dragon. =)

» Go to part II for more techniques!