I also posted the pic for this post DOR123 made he claims the American T8 are dimmer than the T12s and says it has same materials inside....I am not sure where he gets that, but he hasn't been to America to see the proof....
In terms of lumens, F40T12 lamps give more (full wattage lamps at least). These are probably crappy 34W T12s. T8's do seem brighter even though they're not labeled as high in lumens. BTW; Jace did you get my PM?
Yeah compare a full power .8amp magnetic RS ballast with triphosphor F40T12s or T10 to a normal light output instant start T8, the T12 may be brighter! Plus with frequently started applications the T12 is gonna outperform
They are comparing old-school halophosphate T12s to tri-phosphor T8s. Halophosphate F32T8s are not nearly as bright as halophosphate F40T12s, and tri-phopshor F40T12s are much brighter than tri-phosphor F32T8s.
*Looks at the pic* Mmmm... yeah