A set of color conversion filter for Rolleiflex / Rolleicord Bay I:
Warming (Magenta): R6, R12;
Cooling (Blue): B1.5, B3, B6 & B12
Conversion filters for color shots use the European Mired or MD scale, this is a mathematical scale that allows to calculate the filter effect previously. These filters have the letter R (red or reddish) to warm the colors and B (blue or blueish) to cool the colors.
R Mired filters absorb violet and blue and a bit of green light and UV radiation, allowing to pass red and yellow undiminished; B Mired filters attenuates the higher red, orange and yellow components present at the tungsten illumination mainly allowing to pass the blue light undiminished, they can be used for natural light too of course.
Fits for Rolleiflex TLR Bay I Model.