How to change the default checkered background behind transparent renders?

Problem: I’m rendering Freestyle, dark grey toon lines on a transparent background. I’ll composite them on top of other layers, probably in After Effects.

But when I test-render in Blender, it’s hard to see the lines because they’re so dark, and the default background is so dark, too.

I have too many Freestyle line sets to go through them all and change toon line colors to white. Instead, can I change that default background of dark grey checkered squares?

Why it matters? I’m making fine adjustments to objects’ positions, then re-rendering a frame to check if they’re overlapping properly. I need to move an object, see the render, move it again. It would help if I could just see the transparent renders on top of, say, a very light gray checkered background, or pink, or blue.

Can it be done? I can’t find a likely adjustment in User Preferences.

  1. Composite it over something bright in Blender’s compositor.
  2. Use the color selectors (buttoms on bottom right of your screenshot) to display without transparency or e.g. alpha-only.

Thanks, Stan. That’s what I thought: no way to change that background (yet).