Color–magnitude diagrams of the outskirts of the Arches cluster. Blue dashed lines show the color selection used to choose the cluster members and discard background (blue diamonds) and foreground (red diamonds) sources. The Geneva isochrone with the mean extinction value of the cluster members in each field is shown in yellow. The green dot-dashed line represents the approximate mean color of the cluster members in the center of the cluster where the mean extinction is slightly lower.