What Is a Diffuser and Why Do I Need One?

Soft, even light on your plein-air easel is vital. Here how you can achieve it.

Getting the best light on your artwork while sketching outdoors makes a huge difference for seeing color. Ideally you want soft, diffused white sunlight at a level close to the brightness of the scene itself. The worst thing is cast shadows or dappled light across the painting.

Controlling the light on your work can be difficult on a bright sunny day, which is why I came up with this easel-mounted diffuser. Unlike a white umbrella, this setup won't blow over in heavy wind. The diffuser affects the light only where you need it.

The white diffusing panel is made using a recycled Pendaflex frame. These rectangular aluminum supports were used for hanging file folders. Over the frame I stretched white rip-stop nylon and sewed a seam around the edge. The angle of the diffuser is completely adjustable and the whole thing is removable, held in by a wood bracket at the top of the easel.

Here's what it looks like on the side away from me. That bracket is a piece of plywood which is split so that it tightens against the aluminum bar. The wood bracket is held on with a Southco adjustable hinge, so that the whole bracket can fold down out of the way.

Here are a few designs that improve on the classic white artists' umbrella, which has a tendency to blow down. This teaser gives you a sense of what’s in my full video on “How to Make a Sketch Easel.”

Here are more ideas for diffusers, plus a reflector, which can bounce light back into your painting when you’re facing contre jour.

Let’s finish with the system I use now, my favorite kind of diffuser, which incorporates ideas from everything we’ve seen so far.