[T206Collector]

Why does the card look more heavily cut on the back of the "flashing" Gehrigs than the front? It's because the back scan of the SGC version is slightly smaller than the back scan of the PSA version. That's why the lettering moves a little, too.

While I find all of the evidence of cleaning/brightening persuasive, let's be a little cautious about relying on two scans of purportedly the same card under different conditions.

My guess is that SGC did not miss an obvious trim on the Gehrig. For instance, the SGC insert appears to fit snugly -- more so than the PSA holder does.

I took the same back scan of the SGC Gehrig, and then magnified one slightly below. Note how the eye picks up the difference in the bottom border much more easily than anything else.