Pay attention to the number in front of the colour. The "17 Red" is sort of a cranberry colour, I think. "18 Red" is a little bit darker, more of a wine/burgundy. Go lower (16-15-14) and you move towards true reds, and then into fire engine/poppy...
Uniqlo doesn't really do descriptive names for colours, I suspect because they're a global brand and colour names are hard to translate.
ETA: The inseam length on these is listed as 20" (measurements are provided in the Size Chart) -- which would be culotte length on me, definitely shorter than what I'd call a cropped pant.