How To Identify Hugo Black 2172 From 2172B

Separating the Dark Olive-Green 2172 from the Light Olive-Green 2172b can be a challenge at times especially if the 2172 is lightly printed. One simple method is to view the stamp under LW UV (fluorescent black light). The ink on the 2172 will appear olive green while the ink on the 2172b will appear black. The image below was taken under LW UV. The stamp on the left is 2172 while the right is 2172b.

From what I see on the screen, the 2172 shading appears much darker overall while the b issue is lighter. Is this correct?

The 2172's I have seen tend to appear heavier inked versus the 2172b which would make the shading look darker in the pictured examples. Side by side under LW UV the difference in ink color is quite distinct. Getting good LW UV images with accurate color is a challenge.

Nice, effective PICs! The difference is shown very well.

Thanks for the post mstocky2!

I'll have to check mine when I get home and have a chance to.
In your pics above I am also able to see the difference in the block tagging size.
The stamp on the left (2172) has a smaller block tag size than the stamp on the right(2172b). In the pics this is seen by the tagging being taller on the stamp on the right. And width is also wider on the stamp on the right, just not as easy to see.
I think you had told me this also was a distinguishing feature between the 2172 and 2172b.

Dave N.

Dave you are correct. Thanks for adding this detail.