1988 US Carousel Stamp Sheet Printing Error?

Not the first time down this road. Retroreveal came to the rescue in this case:

https://www.stampcommunity.org/topi...PIC_ID=23661

I clearly recognize that there are many examples of color changelings on this issue. The fact is though that these came out of a matt of 50 when I purchased these at the PO back in 1988. As far as sending it for certification, what would the request be of the certification? Just as with the famous 'red missing moon patch' on the airmail C76 the only way it is an error is if ALL TRACES of color are gone. This thread shows examples of clearly tampered or color changed examples of the Carousel horses. That does not preclude the fact that the yellow in my examples and the initial scan are not color changelings in my opinion, but ink running low in the yellow.

Dutch stamps from the 1990s have shown that acquiring stamps from the post office that show a different colour from the official one does not prove it was a printing error. In that case it could by shown by the breakdown of the phosphor in the coating the colour did change after printing.

In this case, storage had broken down colours.

Whereas acquiring stamps from the post office in a different colour makes it more likely they are not colour changelings, it is not a guarantee they are not colour changelings.

As for OP's scan, the sheet clearly shows the yellow at three sides. Unless the printing press applied the ink in some erratic way that would first print the left frame of the left column, the right frame of the right column, the lower frame of the lower column and two frame sides of the bottom corner stamps, the ink starvation just cannot happen.

If these were printed on the web, the ink would progressively become drier in a single direction, which it does not. Also, as Don already remarked, the sharp transition shows that the sheet posted in the original post suffered from light exposure where parts were protected from that exposure.

Yes, a fade.

In 2015, Partime posted this picture



The sheet posted by OP has the colour registration marks and plate numbers (full ink also at the top of the sheet) in the left margin.

Were these printed as multiple panes side by side, or sideways, with the colour registration marks between two counter sheets?

If the first holds, ink did not run to the side, because the left side of the sheet posted by op would have been at the centre of the press.
If the second holds, the opposite margin would not have returned to full inking if it was a dry print.

Wow, blast from the past. Even I can't find that older thread, but I still have those stamps ...

It is the link rogdcam provided at the top of this page.

Thanks, missed that.

How do you get it tested and how much does it generally cost?