Why do i become really dark tanning outside, but reddish copper when tanning in a bed?

[Taylor]

i've been tanning in a bed for a month or so now getting ready for spring break and trying to get very dark like i usually get in the summer, but for some reason i get really dark for like a day and then it seems to turn into like a reddish, dark orangish, bronze color. In the summer i usually get brownish olive, im Italian, native american and german heritage so i have dark complexion, but why cant i hit that deep dark tan in beds?