Ok, I know that it is difficult to accurately determine stamp colors from a scan, but I'm going crazy here trying to figure out all the different colors of the Samoa Palm stamps

Here several of the 2 pence stamps. They are all Perf. 11. Considering the "yellow" (Scott 13e) has the highest CV, my calls on these are as follows:
orange yellow; bright yellow; pale ocher; and brown ocher.

What do you think?
Any further thoughts or suggestions on how to better figure out these colors? (no I don't have any color gauges

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