What impacts skin color in digital photos?

Skin colors are important for a broad range of imaging applications to assure quality and naturalness. We discuss the impact of various metadata on skin colors in images, i.e. how does the presence of a metadata attribute influence the expected skin color distribution for a given image. For this purpose we employ a statistical framework to automatically build color models from image datasets crawled from the web. We assess both technical and semantic metadata and show that semantic metadata has a more significant impact. This suggests that semantic metadata holds important cues for processing of skin colors. Further we demonstrate that the refined skin color models from our automatic framework improve the accuracy of skin detection.