colour variety

JeffS I have done that and really cannot tell the difference, was looking for an opinion. Not holding anyone to it either but you and others on this forum are much more experienced at colour coding than I. One thing I did notice was the paper on the 112 seems to be more toned that the examples of the 112a but this may just be coincidence.

not sure how helpful, but I grabbed a screen shot from your image


Bear in mind that a screen shot is very low resolution.  Also, "Indigo" does not seem to be a universally agreed upon name for a specific color tone
Below are colors labeled in philatelic color guides (M = Michel, SG= Stanly Gibbons earlier printing, SG2= Stanley Gibbons, most recent printing. All scanned on same scanner, same resolution, same settings , and added into PERFOMASTER colortable


and now Indigo Hex # 4B0082

I don't know the dealer, so this is just an opinion. But...

-- the dealer scans a $1000 stamp still inside a dealer card?!?
-- not only that, the card appears to be still placed into a strip on a stock page?!?

Using such a pic to distinguish a minor color variety with a major premium is iffy at best.

Also, note the scanner used tends toward blue and pink. Notice that even the uncovered very top part of the white card isn't evenly white. The scanner is digitizing "shadows"/unevenness as bluish and pinkish. Not sure how that affects the color appearance of the covered scanned stamp.

Unless it is a trusted dealer, since the scan doesn't look like indigo, I wouldn't bid on it unless the dealer can provide a side-by-side comparison of the cheaper SG 112 alongside that SG 112A.

There are several examples of British Commonwealth stamps that were printed in indigo/ultramarine varieties. Here is a typical example using the 10/- KGVI stamp of Great Britain. At left is the 1939 indigo, and at right is the 1942 ultramarine.



To me, if it is a dealer trusted by me, I would bid on it based on previous history of proper ID of stamp varieties. I might question the dealer if the scan appears off. But if the trusted dealer told me it is a scanner issue, I would accept their explanation without doubt -- again, based on previous experience of correct ID of difficult stamps.

Before the internet, it would not be unusual for me to buy stamps sight unseen from trusted dealers. In fact, I would say easily 75%++ of the stamps I have (in terms of both value and quantity) were purchased sight unseen. Nowadays, anybody who can sign up for an online account is a "dealer". But combined experienced & "trusted" dealers are getting harder to find. Hopefully, as the years go by, more and more of the internet dealers will get more experienced...

I'll voice my opinion -- it just may not be correct!

I'm not really good with color shades either -- especially the red or pink shades. You can put pink, rose pink, pigeon blood pink color varieties side by side, and they would all still look the same to me -- some sort of very faded red...

In my opinion (I'm not very good at appreciating colors either) it's a shade of ultramarine (dark or blackish).
From the Michel color catalog:

I'm going through that right now with an early 1900 stamp. It's a "blue" color...but it can't be a simple blue color...nope...there are like six different versions of blue to pick from. It's one of the reasons I stayed away from them as a kid in jr high with my collection because it was just too confusing. Well it hasn't gotten any easier for this old man yet. I have a search in ebay for the "Encyclopedia of the Colors of United States Postage Stamps" to see if one of those rare collections will ever pop up again.

And yes...I know what I will expect to pay...
brookbam

UPU Issue 1949, 3d , Scott 213 stamp has indigo color.
I found it on ebay and compared it with yours:

Here is an RPSL certificate from 1961 for a block of four of SG162a.



Note that they say it is genuine, possibly climatically affected.

Here is the block, itself. Stunning, whether it's just as it came, straight from the press, or it's a victim of climate change.