US Scott 2476 Blue Shift

Curious if anyone has any info on a blue shift for this stamp?

I haven't been able to get my hands on a EFO catalog yet. But I feel like this has to be something.

I appreciate any responses.

Original mint I have:

Blue shift:

I would rate it as a very minor color shift. Some people would say it was undesirable, while some might pay a very, very small premium for it. The desirable color shift would have to be much, much larger.

The shift is insignificant and detracts from the already minor value of 25 cents as the catalog minimum is set.

You will not find an EFO catalog for such an item as as The EFO Catalog only tracks errors. Freaks and Oddities are not cataloged as such.

That said, it is an example from which the direction and the amount of shift is obvious. But still as a technical example of an EFO process, it has little interest outside of a deep specialist collection and effectively zero market value.