Gum bichromate negatives of cyan, magenta, and yellow or red, green, and blue are used for a full-color image. Some photographers prefer substituting the cyan emulsion in the CMYK separations with a cyanotype layer. A simple duotone separation combining orange watercolor pigment and a cyanotype can yield surprisingly beautiful results. Low density photographic negatives of the same size as the final image are used for exposing the print. No enlarger is used, but instead, a contact printing frame or vacuum exposure frame is used with an ultraviolet light source such as a mercury vapor lamp, a common fluorescent black light, or the
Blue–green distinction in language for each of blue (""), green ("") and grey (""). For all three, different shades can be indicated with different (compound) terms, none of them being considered as basic color terms: "bleu " (light blue), "bleu " (sky blue), "bleu " (Navy blue), "bleu " (royal blue); "vert clair" (light green), "vert " (literally: apple green); "gris " (very dark grey), "gris " (literally: mouse grey). French also uses "" for the lighter shade of blue of the sunny sky, that was in turn loaned to English as "azure". Catalan distinguishes blue (') from green (') and grey ('). Other