There are subtle differences in the image quality of T206, with the 150 series being superior to the 350 and 460 series overall. However, one card where this 150 vs. 350 difference seems to be on steroids is Eddie Plank. Here is a side-by-side of my 150 with the 350 that just sold at Mile High:
T206 Plank mine vs Mile High comp.jpg
I don't have enough T206 to do a side-by-side of individual cards that were printed in both the 150 series and later. If you have enough cards to add some side-by-side scans of the same pose I would like to see them - even if there isn't a very big difference. Please try to make sure the registration is good on both cards and there isn't any fading on either. I don't think they will show the extreme difference in color, contrast, and clarity that Plank does, otherwise I think the 150 vs 350 and 460 difference would be a much bigger deal across the set than it is.
Assuming the Plank difference is more extreme, is this why people hypothesized that a broken printing plate may have been why his card was pulled? I never thought much about this, but I always had a visual of this theory requiring a cracked/gouged/chipped and therefore unusable plate, but were people actually referring to the change in image quality as the argument for a broken plate?
I am not arguing that Plank was pulled because of damage to the plate - just wondering about the origins of that idea.