But batlecruiser file have color by choosing color in multiply node (Mix RGB) connected to albedo, that small Color2 field.
All ships able to be flown by capsuleers have grayscale albedo. I think CCP uses some diferently colored materials to colorize the ships (back when SKINS were first introduced, the SKINs worked on every ship, just the metalness and colors changed on ships). CCP probably made it so they would have time saving technology when tweaking the materials for every ship at the same time. They may have expanded whole texturing with SKIN technology introduced, and it was easier to have Albedo in pure grayness.
Materials texture have 4 shades, so it facilitates 4 metallness levels, with 4 colors. I used it with metalness to get it to shine like amarrian ships do. But probably it would be best used like some kind of mask defining materials and colors, not only metalness.
But for Talocan ship that is object in space albedo is colored. The grayscale albedo can be colored too in Texture Paint mode in Blender. Or there is also this option (simpler I think, as fill tool can be used in GIMP) to colorize the materials texture, save it as “albedo colors” and mix it with graysacale albedo by Mix RGB node.
EDIT: I used that recolored materials texture and used it in the example file, please redownload to see how its made now. https://drive.google.com/open?id=15W55AORS5OWzvUe4kmS0F8TbcryktBPq
In GIMP you can convert the Materials texture to RGB colorspace, use mask by color and then fill selected areas, save under some different name and you will have colored ship when you do the Blender node magics…
You can experiment with different settings for the Mix RGB node, like maybe somethin like Darken? With Fac 100 it gives saturated color.