Coloring Tutorial

By Hans Häggström, a.k.a. zzorn.

This tutorial describes the steps used by me to color and shade line art. It covers cleaning up scanned images, doing flat coloring, and adding shadows and highlights. It focuses on the technical aspects, and leaves out artistical advice. I'm using Paint Shop Pro, but it should apply for any paint program with layers and layer modes such as multiply and screen.

For illustration, I'm using a vampire sketch by Siri Austvik, a.k.a. Alien, that I color and shade.

1. Prepare the line art

We start with a scanned or computer drawn line art sketch. If it was scanned, you need to create a cleaned up version that is purely black and white. You can start by duplicating the scanned art layer.

First, you should close any small holes in lines between different areas in the picture, so that the areas are easy to select with a magic wand or similar selection tool in later steps.

To clean up a scanned picture you can use a histogram tool or similar, making all pixels brighter than a certain treshold pure white, and the others pure black. A way to get a smoother, rounded look is to apply a smooth filter on the result (gaussian smooth with 5 pixel radius for example), and then repeat the histogram filtering step for the result. That technique is described in a rounded corners tutorial at Gimp User Group.

Vampire picture with line art layers

2. Color the areas

Now create a new layer, and name it "color". This will hold the flat color areas in the picture.

Use the selection tool to select each garment or item in turn from the cleaned up line art layer. If it consists of multiple disjoint areas select them all (in PSP by holding down the control key when clicking). For each area, perform the following steps:

  1. Expand the selection by a few pixels, so that it continues under the line art, and no white seams are left.
  2. Pick a suitable base color for each garment or item, select the color layer, and fill the area completely with that color using a large brush.

You can edit the color layer by hand to fix any areas that are still uncolored. Now we should have a flat colored picture.

Vampire picture with color layer

3. Add in the line art

We can use either the cleaned up line art drawing or the original scanned drawing to add lines to the picture. We can also use a mixture of both. We don't need to make the white parts in the drawing transparent to show it on top of the color, instead we can just change the mode of the line art and original layers to multiply, and move them on top of the other layers. Then adjust the opacity of the original and/or cleaned up line art as desired.

In the vampire picture I'm only using the original line art, as it was suitably clean already.

Vampire picture with color and line art layers

4. Create texture layers for some areas

In the vampire picture I'm using a colored gradient for the dress. For this I created two new layers (one for the arms and one for the bottom part of the dress). This way I could use a Hue Color Saturation tool to adjust the colors of them separately. I selected an area using the existing color layer, switched to a dress gradient layer, and used a soft brush to add a stripy gradient from the top.

Material textures could be added to the pictures as additional layers this way. It's important to not disturb the flat color layer, because it is used for selecting areas to work on.

Vampire picture with dress gradient layers

5. Shade and highlight

The next step is to add shadows and highlight.

Personally I use four layers, two shadow layers and two highlight layers. It's possible to use just one shadow and one highlight layer too, and use more varying opacity for the brush. Fewer layers are also easier for slower computers to handle.

Create four new layers, labeling them strong/weak highlight and shadow. Change the layer mode of the shadow layers to multiply, and the mode of the highlight layers to screen. Adjust the opacity of the weak layers to 30% or so, and the strong layers to around 60%. The shadow and highlight layers should be on top of the color layer, and usually the stronger shadow/highlight layers are on top of the weak ones.

Select each color area in turn from the color layer (in Paint Shop Pro, remember to turn of the "merge visible" checkbox for the selection tool, so that only the information on the flat color layer is used for selecting). Also make the color of the area the current color. I used opacity 30% or so for the brush. Then switch to the weak shadow layer, fill in shadows, and repeat for the weak highlight layer. Lastly add the strong shadows and highlighs.

Vampire picture with color and shading

6. Create the background

Draw the background on a separate layer. You may also use a few different background layers, for example to shade over parts of the backgorund picture with darker color to make it more uneven, to add a bit of light to the ground close to the viewer, and to add some shadow directly under the figure. You can also use some existing noise or natural texture for the background if you want to make it more abstract.

Vampire picture background

7. Final details

Then it's time to do a final adjustment of the opacity of the shadow, highlight, and other layers. I tend to shade a bit lightly, so I usually increase the opacity of the shade and highlight layers a bit. Play around until you are satisfied with the balance.

At this step I also added a layer with some white on the teeth of the vampire, credits and signatures, and other details.

Vampire picture with all layers

And here's the final vampire picture:

Full vampire picture

If you want to have a look at the layers, the original Paint Shop Pro picture is also available. It should open in Gimp too.

References

Here's a few sites with useful tutorials: