Various implementations disclosed herein include devices, systems, and methods that select colors for visual markers that include colored markings encoding data. In some implementations, the colors are automatically or semi-automatically selected. In some implementations, the colors are selected to remain sufficiently detectable despite changes in lighting conditions or printing/display conditions. In some implementations, a set of colors selectable for use in a visual marker is obtained. Then, measures of distance between a plurality of colors of the set of colors is determined, and a subset of the set of colors for the visual marker is selected based on the measure of distance between colors of the subset of colors. In some implementations, the visual marker appearance includes graphical elements encoding data using the subset of colors. In some implementations, input is received using a GUI on a display to determine multiple colors based on a source image.