Chromatic aberration can create luminance artifacts at isoluminous-colour borders.
We tested whether observers, when instructed to equally defocus abutting red and green, could accommodate as to yellow, so that luminance artifacts would be reduced. Accommodative performance was compared with that with monochrome red, green, and yellow. Observers were able to focus the target intentionally. This implies that instructive control of accommodation may serve as a means for reducing luminance artifacts at isoluminous-colour borders.