I've always had a thing for revenue double impressions. However, outside of the 1st issue double impressions, many revenue DI, especially those of the 20th century, are somewhat "meh" in terms of dramatic appeal. Especially in the documentary and proprietary issues, some of the doubling is so minute that unless you're examining the stamp under high magnification you can't actually see the doubling; it just looks like a poorly inked stamp... in fact many dealers and eBay sellers offer inking anomalies as double impressions when they are not.
The secondary impression must be uniformly in one direction. For example, "doubling" which is ink spread in all 4 directions outward from the center is an inking anomaly not a double impression.
I've tried to stay away from the borderline examples. I want to see distinct separate impressions at a glance. I want the stamp to SCREAM double impression at me!
Here are some of my favorite non-1st issue revenue double impressions in my collection:
Here's a good comparative example of "meh" vs. dramatic, in my opinion. First is a block of 4 of R234, that while doubled, is minimal, so it just looks at first glance like a poorly inked stamp.
Now contrast that with this block of R229, where the doubling is much farther apart creating clear and distinct doubling of the design. This is the type of thing that I gravitate to.
Having the double impressions in blocks also makes for a great visual presentation.
So... fast forward to the most recent Kelleher auction. They had a reconstructed used block of 4 (2 horizontal pairs) of RB67, the 3-cent Proprietary stamp of 1919. This is yet another case where the catalog value ($70 per stamp) is NOT an indicator of true scarcity. It's only listed mint, not used and Kelleher posited that these could be the only used examples extant... not that it really matters, as I don't recall ever having seen an example of this DI mint or used. I've reached out to Eric Jackson and Richard Friedberg to find out whether they've had examples of this particular double impression. Richard responded that he doesn't recall ever having an example, mint or used. I'm still waiting to hear back from Eric.
Bidding was quite spirited and I had to pay well above Kelleher's estimate, but still a comparative bargain in my opinion based on scarcity. This definitely falls in the category of "pay what it takes as you don't know when you'll see another", or as Denny Peoples would say "Yeah, I dare you to find another one!".
It has that clear second impression that I want to see.
It could very well be the only multiple extant.
Any ideas on the company?