Okay, here we go.
This is probably the most confusing group of errors ever created and it's because there are two different errors and they both involve "white letters." They're both referred to as "white letter variation" but they're both different. I'll break it all down here in this post.
Let's start with the most difficult to find.
In the Future Foundation subset (FF from here on out), all of the base cards have their names on the front printed in white letters (like yours). The silver signature cards have their names printed in silver and the gold signature cards have their names printed in gold. Here's a non-error Jeter silver signature to show you the silver name:
The error is that some of the silver signature cards had their names on the front printed in white instead of the silver. If your card does not have a facsimile signature on the front it is not an error.
Unless....
It is one of the second types of white letter variations. On the back of the FF cards, the first letter in the bio is enlarged and colored grey. See below:
See the enlarged 'D' in his name where it starts "Derek Jeter progressed nicely in his second season..."? Some of the FF cards were printed with that first enlarged bio letter printed in white. Here's an example of an ARod with the white enlarged letter:
All FF cards can be found with either of these variations. The variations are referred to as the Silver Sig White Letter variation and the White Letter variation.
Obviously, this whole thing is a recipe for mass confusion. It took me a hell of a time before I was able to sort it all out myself. I hope this helps and if there are any questions I'll do my best to answer them.
Arthur