"Didymium photographic filters are often used to enhance fall scenery by making leaves appear more vibrant. This is accomplished via the special properties of the substance which causes the removal of part of the orange region of the color spectrum. When present, this group of colors tends to make certain elements of a picture appear \"muddy\". Didymium is also used in calibration materials."@en . "Didymium photographic filters are often used to enhance fall scenery by making leaves appear more vibrant. This is accomplished via the special properties of the substance which causes the removal of part of the orange region of the color spectrum. When present, this group of colors tends to make certain elements of a picture appear \"muddy\". Didymium is also used in calibration materials."@en . "Didymium"@en . . .