Feathered dot

I glued the computer-printed irises onto the 1.5" wood knob eyes. The knobs got 3 coats of white acrylic paint.

The most important element to put into the iris image is a tiny feathered white dot somewhere in the center area of the iris. The white dot infers reflection. Without it, the eyes look lifeless.

The final step is a coat or two of glossy varnish to give the eyes a wet look.