BW Base Set Full Arts - Difference between grey and black background?

[rtas]

Zekrom was first printed with a “gray” background and later corrected with the black background (PSA has three labels, cause psa). Here they are side by side:

Few years ago, there was a couple of threads pointing out a small difference in the outline of Reshiram’s hair. It’s very difficult to see in a scan because of the silver on white background. (PSA does not differentiate this variant)

Reshiram and Zekrom Full Arts from Black and White

I was watching Rusty go through some packs in this video and at 13:30 he begins to describe the different backgrounds of the Reshiram and Zekrom Full Arts. I’m fully aware of the two colorations of Zekrom, the black one and the gray. I haven’t been able to track down the differences or notice any in the Reshiram, however, and was just curious if I’m straight up ignorant or if this was just a slip of the tongue. Now that I brought it up, I’m also interested to know which version of the Zekrom (…

Here’s a zoomed in comparison:

Japanese prints do not have these variants (and also have fantastic texturing), not sure about other languages.