Explanation of Catalog
GENERAL OBSERVATIONS - No identification for such things as paper folds or district name overprints which are inverted have been made, although double name overprints are. Where CTO cancellations are known to exist, they have been flagged with a "*'. If you know of others not so designated, let us know. This will help collectors in determining if a stamp needs to be certified. Note that a variety of such overprints exist and we will try to add a display of such in the near future. Numerous color varieties have been observed, but only a limited number have been given a separate listing here as a more complete listing would number in the hundreds.
When no price is shown for a Regular Issue, either mint or used, it indicates that no such stamps are thought to exist. If you have one that is mint and not pen invalidated, send us an image. If you have a used one, get it certified since it is truly rare. Don't send us a used copy that may be a CTO since we do not expertise stamps. When a stamp is a variety, we often show only one price in the Variety Price column to indicate that it is the same whether mint or used. Where we suspect that no used copies exist, only a mint price will be shown. Again if you have one, let us know.
Having examined hundreds of these stamps, the following observations should be noted:
Mint stamps generally have no gum. Mexican collectors preferred this back in the 1800s because of humidity. Those with gum generally have extensive paper remnants and thin spots. Mint never hinged stamps are almost non-existent and should be priced at a significant premium.
All stamps are perforated 12x12 mm with slight variations. No exceptions were found except in the completeness of the perforation. Due to the poor paper quality stamps were frequently separated by being cut with a scissor. Miss-aligned perforations are plentiful. Imperforated pairs and multiples exist. Stamps with four clean perforation edges in the thin paper issues are less common and should sell at a premium.
Scott Catalogue recognizes only two paper types (thick wove paper, some showing vertical ribbing(1879) and thin wove paper(1882). The 1879 issues, however comes in both thick (1879) and medium soft wove paper (1881) as do many of the 1882 issues. No attempt was made in this catalog to identify medium soft wove paper varieties. All paper types are easily distinguished by feel.
The indicated pricing for stamps is based on relative rarity with $200-$300 for items where less than 10 copies are believed to exist unless lesser quantities are known. Errors and varieties are generally priced at $25 above the normal issues' price. When no price for a regular issue is shown it means the stamp is not known to exist in that condition.
Scott catalog pricing for issues without overprints may be higher or lower. For those where the price is higher, this should be respected since a larger collector interest for such stamps exists. Where Scott provides pricing for overprinted copies, this catalog represents a more accurate value given the vast disparity in quantities per district.
Paper folds are common with the thick paper issues as are papers in different shades and with toning. The 1c is found on brown paper and 10c stamps are frequently found on blue paper. Used stamps exist both with postal cancels and CTO cancels of various type. Again the CTO cancellation was done by dealers to accommodate collectors who back then preferred used stamps, hence we have avoided referring to them as bogus which implies that the cancellation was done to enhance the value. In fact, many issues are rare or nonexistent because of this practice.
Pen invalidate stamps are numerous and are clues to stamps which are rare in mint or used condition. In short, it is the only condition you will be able to buy that issue. Note that such stamps almost always come without gum. Generally, where a stamp exists in mint form, they are priced at half the mint price. If no mint stamps exist, they are priced at the mint price level. CTO stamps should also be priced at half the mint price or the same as a pen cancel when no mint stamps exist.
Some 400 errors and varieties are listed here and likely, many more exist. Simce many errors leave a doubt as the district they were intended for, a recap of such errors is shown under the listing for stamps without a district number with a location guide. Note that many of these errors may be printers waste. Over time, as we see no used copies, this will become more obvious.
Where we suspect that an overprint is a fake, we have so indicated. There are relatively few such items since such an activity was not worthwhile until relatively recently and is now made difficult by the shortage of stamps without an overprint.
As a general observation, except for the 7 largest districts (See the table for the issuance by district), the remaining districts' entire stamp usage numbers only an average of 1300 stamps per value/number combination and the survival rate after 150 years is probably no more than 10%. Hence, if you are going to wait until a F/VF copy comes along, you will have a very limited collection after decades. Look for discounts from the prices shown here for condition shortcomings, but keep in mind that the vast majority outside the larger districts are hugely underpriced no matter the condition. For most of these stamps you will only have one or two chances in a lifetime to buy them. Dealers today have priced their inventory without benefit of the guidance this catalog provides. Expect this to change, and soon.
Note that a hard copy catalog published in 2014 in English and Spanish is available for those who wish to obtain more background and issuance information. The price is $29 plus $5 postage and can be ordered at firstname.lastname@example.org
Redirected Issues - Many issues for the years 1980 through 1982 were printed in advance and then found not to be needed. Such issues where subsequently sent to other districts and bear the name, if not the number of the new district. Such issues are shown both as redirected under the district whose number it bears along with a second listing for the same issue with the notation "ENTIRE ISSUE REDIRECTED." This protocol was followed since some issues were sent to the correct district and used in part there before being returned and sent out to the redirected district. Note also, some redirected issues had the district number altered through an overprinting of the original district number. In this case, the listing will be found under the redirected district.
Habilitado Issues - Such issues are identified by the presence of a second number on the stamp representing the district to which it was redirected. This second district overprint appears to have been instituted to clear up confusion caused by the mismatch presented by Redirected Issues. The second overprint was first done in black and then in red to avoid more confusion as to the real district. Most such stamps bear only the second district's name overprint if they bear any at all. A few bear the second name overprint as well which would indicate they were sent out and returned from the original district. We would appreciate notice and images for any such cases.