It really depends on the graphic novel itself and what the person colouring it is comfortable in.For the most part a lot the books out there are coloured by computer using Adobe Photoshop or similar...
yes they do in doing graph design you need to know the angles intersections, it has a little of algebra but it has more geometry alot
Only the ones whose work looks good.
Many graphic designers use a combination:
Prismacolor colored pencils Verithin colored pencils Col-erase colored pencils Nu-pastel hard pastels Prismacolor watercolor pencils
Each have a different...