Quote Originally Posted by F4user View Post
paper is sensitive purple and yellow that mean red and blue and yellow.
red safelight is not a good choice because the paper is sensitive to magenta and magenta is not monochromatic like light, magenta is red and blue.
i think some kind of orange can be a choice for LED safelight, between red and yellow posible to be a gap in paper sensitivity. No idea if green could be a choice for safelight, tests or sensitivity curve could reveal that.
if you want low contrast use yellow filter, if you want high contrast use red filter, blue spectrum is there as any paper have.

Variable contrast is a balance between red and yellow light.
I won't get into whether Magenta has a wavelength all of its own, but I would like to read more about paper being sensitive to it, as well as "Variable contrast is a balance between red and yellow light".
Dichroic filters remove wavelengths of light; Specifically Magenta removes green and yellow removes blue. If white light is not used as a start, and only red and yellow light are used then VC papers (being sensitive to green and blue in everything I have read) won't be much exposed at all.
Perhaps Oriental papers have a different chemistry than other VC papers