Ilford's fact sheet on XP2 Super indicates that the negatives are "usually pink or red-brown and slightly darker than other black and white negatives".(posted 9117 days ago)The negs from the only XP2 Super roll that I've shot are strongly purple-colored. Does this indicate inadequate fixing? If so, should I fix them in a B/W fixer? I don't have any color chemistry, and don't know if color film uses a different fixer.