Tiffen's 62mm #21 Orange Filter is intended to increase contrast and enhance separation between tones in black and white photography. The filter absorbs blue and blue-green colors, darkening blues in landscape and aerial photography, as well as water in marine photography. Due to the filter's filter factor of 4.5, you must boost your exposure by 2/3 stop to compensate.
Tiffen filters are not dyed, but are manufactured by using ColorCore technology. This process laminates the filter material between two pieces of optical glass and grinds down and polishes the glass. The glass is then mounted to the metal ring, which after that can be screwed onto the lens for the desired effect.