Much of the following has been transcribed from Leo V. Corbett's "The Imperial Eagles of Maximilian's Mexico"

Considering the state of the art in the 1860's it should come as no surprise that the colors of the Eagle stamps vary considerably. Ink was mixed when needed and with the ingredients available at the time.

In most cases, color in and of itself is of no importance to the commercial value of the Eagle stamps.

CAVEAT EMPTOR: Please note that color perception is subjective. The following may be taken as a guideline, but you should not rely on the color names alone. Use your own judgement, and remember that there's no substitute for personal experience.

Medio real

The medio real Eagles show perhaps the widest range of colors and shades across the five periods: from dark brown, purple and reddish lilac to shades of gray and even a greenish gray.

Mexico, brown.
Image courtesy Doug Stout.
Durango, claret.
Invoice 156-1864.
Guadalajara, reddish lilac.
Invoice 55-1865.
Mexico, gray.
Invoice 17-1866.

First period medio real Eagles are found in two brown shades, suggesting that at least two printings were made to make up the first delivery. One shade is the light to dark brown, while the other is a reddish or bluish brown resembling the brownish lilacs used in the second period. These last shades are close enough that they are misidentified on occasion. Consignment 11-1864 to Jalapa consisted of stamps in both shades.

14,081 of the brown stamps were sent in the first period, leaving 1,219 to be used in the second period. Calvert Stier identified these brown stamps as follows:

Medio real brown used in second period
Invoice District Stamps sent
118-1864 Guanajuato 100
119-1864 Mexico 500
129-1864 Queretaro 100
132-1864 Jalapa 100
138-1864 Mexico 120
141-1864 Morelia 100
144-1864 Mexico 100
158-1864 Puebla 99

The remaining 3,801 medio real stamps sent in the second period stem from perhaps three different printings. Consignment 156-1864 to Durango is a deep claret color, while the two other shades are a reddish lilac and a purplish lilac. The reddish lilac can be found on invoice 155-1864 to San Luis Potosi and 164-1864 to Isla del Carmen, but most stamps from this printing seems to have been sent in the third period, on invoice 185, 186, 189 and 224.

In the third period we see another reddish lilac shade on invoice 241, 243 and 244, as well as on fourth period stamps up to at least invoice 55-1865. A violet color is found until at least invoice 115-1865 to Puebla (this consignment consisted of two different shades), and on some fifth period stamps.

One puzzling stamp exist from the fourth period: a single copy of Guanajuato 130-1865 has been found in the later fifth period gray shade. This invoice was sent nearly four months prior to the printing of the fifth period grays! This stamp may stem from an adjustment sent sometime in 1866.

At the end of the fourth period there were 400 stamps left in the lilac shade. These stamps were sent to Mexico on invoice 1-1866 and 17-1866. Perhaps less than 10 of these lilac stamps exist today.

At least four printings of the medio real stamps had a gray color, sent to the districts in 1866. One single copy has been found from invoice 1-1866. The range of shades go from very light gray, greenish gray and silvery gray to a brownish gray. Some of the brownish gray stamps were sent to Saltillo in consignment 34-1866 and they have been confused with the browns from the first and second period.

Most of the unauthorized reprints come in a color similar to the reddish lilacs used in the second and third period. Unused stamps should be expertized, particularly those with invoice number overprints 140-1864, 197-1864, 221-1864, 227-1864 and 193-1865.

Un real

The basic color used is blue in various shades. However, a few distinct shades do exist, as I'll try to describe in the following. Please remember that color names may mean different things to different people. As always, use your own judgement.

The first printing of un real stamps was done with a pure ultramarine ("Royal Blue"). The second printing was in a shade between this pure ultramarine and what is commonly known as ultramarine. The third printing was ultramarine and the fourth was closer to blue. In the fourth and fifth period we therefore see blue stamps, as well as some described as indigo.

The third period is rich in shades and will therefore be considered in some detail here.

Un real shades on third period stamps
Color Invoices
Bluish ultramarine 180-3, 186-7, 189, 194, 196, 207, 216
Light blue 185, 191-2, 195, 232, 235, 240
Light ultramarine 190, 198, 201, 204-5, 212, 218, 220
Very light ultramarine 187, 199, 206, 208, 210, 219, 224
Dark ultramarine, bluish 184, 194, 200, 202, 209, 211, 217, 221, 223
Indigo blue 220-1, 228-30, 233, 236-8, 240, 242

Stamps from the following invoices do not fit this scheme very well: 184-1864 to Soyaniquilpan (bluish ultramarine, printed from a worn plate), 217-1864 to Guanajuato in a very light ultramarine (dry print), as well as 229-1864 to Mexico and 235-1864 to Pachuca (without name overprint) in blue, printed from a fresh (or cleaned?) plate.

Dos reales

The colors used run the gamut from deep, rich orange to bright yellow, with some reddish shades resembling an ocho reales color. Some reddish shades are changelings manufactured by a Mexican chemist long ago.

Cuatro reales

The nine deliveries probably contained stamps from several more individual printings. The colors range from very dark green on the early printings, to the light, washed out appearance on the later printings. Since the green color is composed of blue and yellow, it is not surprising that we find shades we call blue-green, yellow-green and even blue without a trace of yellow. The true blue-green shade is very scarce.

Corbett believes that the blue cuatro reales stamps are either proofs, an error or perhaps even an unauthorized printing. It is rare, with only two known copies. This blue color resembles the indigo blue used for some un real printings.

Ocho reales

The six deliveries, possibly from more than six printings, resulted in various shades ranging from light red to deep red. A vermilion shade may also be found on occasion.