What Does A Reference Layer Do?

The main purpose of a reference layer is to help you color line art faster, by identifying those lines and using them as color borders.

 

To me, coloring line art is Clip Studio's killer feature. I haven't found a better workflow in any other program. It's amazing.

 

But some of the coolest tools are hidden under menus.

 

Let's get started with the...

45-Second Reference Layer Tutorial:

Here's how it works:

 

Create a layer, then make it a reference layer by clicking the lighthouse.

Do some linework.

Go to another layer and start coloring.

Your coloring should stop at the lines.

 

Did it work? Great! You know how to use reference layers! Tutorial over.

 

Did it not work? Or were the borders weird? That's because Clip Studio hid some of the settings you need to change, deep in the brush tools menu. Time for the...

 

Much Longer Reference Layer Tutorial:

If your drawing tool isn't respecting the lines in your reference layer, it's probably not configured to do so. To fix that:

 

Click on the options button (The wrench icon) in the tool properties palette.

 

Select "Anti-Overflow" from the menu.

 

Check "Do not cross lines of reference layer."

 

For good measure, also check "Fill up to vector path," and "Area scaling." Change the "Area scaling" value to "1." We'll go over these settings later.

 

Clicking the little eyeball box next to the setting will cause that setting to appear back on the main tool properties palette, for easier access. I always to that with "Do not cross lines" because I toggle it off and on frequently.

 

The good news is that this setting works with just about every tool in Clip Studio. The pencils, the pens, the paint brushes, the bucket fills, the decorations. You can enable anti-overflow on all of them. The bad news is, you have to do it tool-by-tool. I don't know a way to force all tools to adopt anti-overflow.

More reasons it's not working:

 

You're trying to color directly on to your reference layer. Select a different layer.

You didn't actually set a reference layer. Make sure you can see that lighthouse icon next to it.

You accidently made a selection somewhere else. Hit Ctrl-D (Command-D) to make sure there are no selections active.

You're trying to color on an object layer. Just make a new raster layer and try that.

Your brush is transparent. Hit C to switch back to an opaque color.

When it's working, but you don't like the way the color interacts with your line edges:

 

Antialiasing on your lines. I keep it off, always. It's not worth it. Antialiasing creates semi-transparent pixels around your line, and it forces the coloring tool to determine how far into them to draw. You can control this with "tolerance," but it's fiddly, it's not exact and not worth it. If you're drawing at such a low resolution that antialiasing makes a difference in the quality of your finished work, quadruple that resolution.

Why Vector Layers Are the Best For Linework:

The difference between raster and vector layers lie largely in how your computer understands them.

 

A raster layer is a grid of pixels. When you draw a line with a pencil tool, you see a grainy line, but your computer understands only that there are a bunch of semi-transparent pixels in exact locations on a grid.

 

A vector layer is made of math. When you draw a line with a pencil tool, you see a grainy line, but your computer understands the starting point, the ending point, some curve data, and some thickness data, and it uses that information to generate semi-transparent pixels in exact locations.

 

Tl;dr, your computer understands that a vector line is a LINE, instead of just dots in a grid.

 

All that means is that, when you're done drawing linework with vectors, it's easy to change thickness, move the lines, switch from penwork to brushwork, and enlarge without losing sharpness.

 

And, it's easier to color.

Examples From the Video

Cartoon for Trade Magazine

Used the pencil tool on a vector reference layer, set my colors to "Fill to vector layer," and used a perspective ruler to draw in a whole bunch of boxes quickly. I'm kind of obsessed with going faster, hence all the white space and learning the time-saving tools.

Corncob Icon for Mobile Game

I'm not using any lines for this game art, but I am used to drawing with lines first, so I quickly traced a corncob and used the lines to help the shadows and colors stay where they were put. Then I hid the line layer and had a quick painting done.

Caricature for Convention Event

Event caricatures are paid by the hour and I feel a lot of pressure to draw a lot of people with humor and accuracy as fast as I possibly can. If I limit the colors and use some CSP scripting, I can get it down to 2-3 minutes per person. I fill the head with white, lock transparent pixels, and use the linework as a reference layer, and I'm able to slap in basic colors at top speed.