When you spend a lot of time looking at Blue Volume Ones, either in person or on the Internet, certain trends become apparent, such as which countries will usually have the most stamps and which are likely to be barren. It is also hard not to notice that certain countries and issues are frequently misidentified by collectors. Here is a look at some of the more common problems (most of which I've perpetrated myself at one time or another).
ANTIGUA & MOST BRITISH COLONIES
Most British Colonies used key types with the head of the reigning monarch. The Queen Victorias are reasonably identifiable, but collectors who aren't paying attention are likely to mistake King Edward VII for George VI or vice versa, especially where the colors and denominations are identical. On the surface of it, the "baldies" as the Edward VIIs are affectionately known should be easy to distinguish, but, of course, you often are dealing with stamps cancelled over the obvious identifying bits.
And, by the way, regular/commemorative stamps overprinted to make them function as Officials, etc. don't belong in the spaces "up front" (unless, of course, you've made the decision to let design trump use).
AFGHANISTAN
Some collectors throw up their hands at the first sight of non-Western alphabets or non-Arabic numerals. In my experience, if the collector has mis-mounted a lot of Afghanistan stamps then they probably can't be trusted with Armenia, China, the French Offices in China, the Indian Convention States, Saudi Arabia, et al.
AUSTRIA
The various profile heads of Emperor Franz Josef between 1890 (Scott 51) and 1907 present challenges depending upon whether the numerals are black, white or colored, whether the numerals are surrounded by ovals, squares or hexagons, the currency used, etc. You've got 49 spaces to get it right, wrong, or as probably in my case, somewhere in between.
BELGIUM
For the past several years I've been blithely completing a page in the Blue of Belgian Parcel Post/Railway stamps, congratulating myself as the page rapidly filled up. Imagine my chagrin to discover that many of my stamps were in the wrong place. In my last eBay purchase something or the other sent me to the Catalog to verify a stamp only to discover that practically every stamp I had mounted in the 1916-1920 spaces was wrong. So I went from having virtually every space filled for these to having only two. I'm sure there were stamps in previous album purchases that I ignored because I thought I already had them.
The top row in the album is straight forward for the stamps from 1912-14. But things go downhill for the remainder of the page. My take on this is the first two rows are intended for Q61-80 from 1916 which have the values at the bottom only. The next two rows are for Q82-102 from 1920. These have numerals at the bottom and top. They can be distinguished from the following set because their winged wheels are filled/shaded. Then the last row is for the stamps Q103-Q131 from 1920-21. These also have values at the top and bottom but have no fill in the winged wheel. (Distinguishing between the stamps with the train in all these issues is much easier than the winged wheel. As is often the case, the Minkus Global albums offer collectors more help via useful notes like "Shading on wheel-spokes" or "One head-lamp in Engine.")
An interesting survey of these stamps can be found here.
CAPE JUBY
The Blue contains several colonies like Cape Juby, Dahomey and Martinique where there are multiple pages with zero illustrations, only descriptions like "Stamps of Spanish Morocco, 1935 overprinted." Well, I suppose Scott has to sell its catalogs somehow. Anyway, the lack of illustrations is an invitation for collectors to make mistakes.
FINLAND/RUSSIA
I left this out of my original post because until now I've never taken the time to verify my own holdings. I knew there was the potential for mistakes because Finland and Russia used similar stamp types between 1891 and 1918. Turns out that I had erroneously mounted one of the Russian Ring stamps in Finland, and the original owner of my album had hinged a similar Finnish stamp underneath the correct stamp in Russia. So all in all, not too bad. It also makes me feel better because in looking for suitable illustrations, I found some misidentified stamps on other web sites.
For Finland, here is the breakdown for the stamps in the Blue Volume One:
1891-92 Scott #46-52
Denominations are in Kopecks so that doesn't help to differentiate from the Russian issues. Look for the circled dots along both sides of the ring or in the corners.
1901-03 Scott 64-68
Finnish stamps will be denominated in Pennia, not Kopecks, or, in the case of #68, 1 Markka (which, as we all remember from Elementary School, equals 100 Pennia).
1911 Scott #77-81
Finnish stamps will be denominated in Pennia, not Kopecks.
There are more examples in this Stamp Identifier.
For Russia, just look for stamps without the circled dots or denominated in Pennia, Markka.
FRANCE/FRANCE COLONIES
The second space for France is intended for the 25 centime blue from 1849-50, Scott #6. However, what is usually in the space is the rather more common French Colonies #12. A number of early French stamps are difficult to distinguish from those intended for the French Colonies which didn't have their own stamps. While this isn't the fault of the Blue's editors, it would be nice in this and similar cases if there was some sort of caution in the album to send collectors to the Catalog. Minkus did this for France in their Master and Supreme Global albums: "For other stamps with the following designs see French Colonies--General Issues."
GREAT BRITAIN
No one reading this column is going to make this mistake, but you'd think that the Penny Black is sufficiently iconic for all collectors that the space for it would either contain the right stamp or be blank. So I'm surprised how often the wrong stamp is in the space--usually one of the Penny Reds, on occasion even perforated! If someone wanted to fill the space while waiting for the Penny Black fairy to come through, there are always the many stamp-on-stamps of the Penny Black, such as the 1990 Great Britain miniature sheet issued on its 150th anniversary.
ITALY
I've yet to see a Volume 1 that had the correct stamp for Italy in the space described as "Type of 1862, Imperforate." Assuming that it isn't blank, the stamp in the space is invariably #23 or #23a, not #22 with the head embossed from 1863. Although the description in the current Blue is technically correct, it was a little more obvious in earlier editions which had 3 earlier stamps similar to the stamp that belongs in the space. These three 1862 stamps are missing from later editions.
LATIN AMERICA
I have made no attempt in my own collection to try to weed out "the Seebecks" and probably won't until I get to the point of needing to make more expensive purchases. If you are unfamiliar with this topic, check out Keijo's blog post: http://www.stampcollectingblog.com/seebeck-reprints.php
PERSIA
The Blue I first purchased was probably 90% complete for Persia. However, I have read many times that much of the Classic Era Iran typically found in collections are counterfeits/reprints/forgeries. So I'm saving until some future date (if ever) trying to make sense out of what I have.
UNITED STATES
I'm not going to talk about the USA even though grills, secret marks, and watermarks offer much opportunity for, shall we save, creatively filling spaces. Just watch out for albums with Blue 5c "1847" Franklins!