Mono channel speculars

[MarieRose1301]

I'm having an issue with custom materials and specular maps
I intended to use a specular map with SSS material, however after leaving only 1 black and white channel on the texture I get an error saying that the map is RGB. how should the texture be saved in order for ray to read it as a mono channel texture? I've tried saving a black and white 8-bit jpg and png but none worked

[ray-cast]

just sets the SPECULAR_MAP_TYPE to 2 and also, you can specify the channel by SPECULAR_MAP_SWIZZLE