Originally posted by ivanvernon Sorry for the error. Here are the three filter inscriptions, in order from top to bottom: clear, pale green, and amber.
Here is the description from the English user manual:
"The light filter YG-1.4Х, yellow-green and light, improves the tone reproduction of multicolor objects on high-sensitive
photo materials with a slight loss of their sensitivity. With medium-sensitive photo materials, the practically correct tone
reproduction of multicolor objects is attained.
The light filter B-1.4Х, blue, requires a slight enlargement of exposure and is the most suitable for taking pictures with
filament lamps as it provides for the correct tone reproduction of color objects especially in taking pictures with the use of
high-sensitive photo materials.
When shooting outdoors (in the day lighting) the blue light filter singles out a haze, improves the image of shades in a
sunny day, provides for the more correct reproduction of space.
The light filter O-2.8X, orange, fully absorbs Ultraviolet Rays. It is used to obtain a particular contrast in shooting the
compositions with clouds, water surfaces, landscapes with a noticeable shading of verdure, etc."
The O likely denotes orange and the 2.8
x denotes the f-stops the filter reduces the light level.
Apologies to all for any appearance of thread-jacking; I really come here to look at the photos.