657 Lake Color Error?

I recently purchased a sheet of Scott 657 and believe it may be 657a. I laid a plate block of a known 657 on the right and a single I believe may also be 657a on the left. Any opinions on the color differences would be appreciated. I'll be sending off for a cert next week either way, just curious to find what others think. Thanks!

I would expect to see a little more blue in the lake version.

Here`s one from Kelleher Auctions.

Your sheet of Scott #657 is definitely more blue and closer to "lake" than your plate block of a known #657 on the right. However, every single printing of U.S. classic stamps has a wide range of color variation.

Things such as color calibrated scans and in person expertizer opinions are necessary to determine if a stamp's color variation is significant enough to be considered a variant. Without color calibrated scans and yet-to-be-determined quantifiable color measurement, you can only submit them for expertization and hope for the best.

Given the above, your "single I believe may also be 657a on the left" is different enough that it COULD actually be a 657a. I highly doubt that your sheet could be 657a.

Accurately displaying color across the Internet is very difficult. Quantifiable measurements of color are also very difficult and are not yet established. My input is merely conjecture. However, I do believe that the comparisons between the three stamps all in the same photograph are likely accurate enough that I can say that your sheet is not #657a.

Regardless, good luck!