Evans' research interests include the improvement of visual quality in image processing systems. Many printers render pictures (e.g. scanned photographs) using dots on white paper. On the paper, a dot is present or absent. The process of reducing hundreds of shades of gray on a desktop monitor to on-off dots on the paper can significantly degrade the quality of the printed image when compared to the original. Lower resolution displays on cell phones and PDAs perform a similar operation. This operation to reduce resolution of gray levels or colors is called halftoning. Evans' group has developed grayscale and color halftoning algorithms that are optimized for a model of visual quality. The halftoning algorithms are amenable for cost-effective implementation in printers and displays.