Carter Numbering System
Carter's fountain pens are characterized by a numeric code imprinted on the bottom of the barrel, which identifies the model. The code is found predominantly on the flat top versions in celluloid produced from 1927 (the Carter Coralite Pen), but is also found for the following streamlined versions and on the Pearltex versions (the Carter Pearltex Pen).
The numerical code consists of four or five digits (depending on the color code that can take one or two digits). The units digit indicates the size of the pen, and with this also the overall size of the pen. For Carter Coralite Pen the number starts from size 2, the smaller, to size 7, the greatest. For Carter Pearltex Pen these measures start from size 2, the smaller, to size 8, the largest.
But for a given size of the nib there are variants in terms of length of the pen and of the diameter of the barrel, for which there are three different alternatives, which are indicated in the numbering from the next two digits. The tens indicate the length of the pen that it was available in three variants, long, medium and short, marked with numbers 1, 2 and 3 according to the table at right. The hundreds instead indicate the size of the body of the pen, this one made in three different variants, large, normal and small, with the numbers 1, 2 and 3 in the table on the left.
|10xxx||Coralite Lacquer Red|
The first digit (or the first two digits) of the model number indicates the color and material the pen is made, which are different depending on whether it is a Carter Coralite Pen or a Carter Pearltex Pen. In the first case some were still produced in hard rubber. The color table is shown at right, the colors are: Red Polished, a solid red; Black Polished a solid black; Black Chased an enchased solid black; Red-Black Mottled, a black mottled with red; Coralite Blue a dark blue marbled; Turquoise Blue (?) brown with red; Gray Squirrel a tone from pink to lavender; Coralite Green, the classic jade green; Coralite Lacquer Red, a coral red.
The Red Polished and Black Chased colors were made in hard rubber, the Black Polished and Red-Black Mottled were made in both hard rubber and celluloid, the other colors were only made in celluloid, and they are the ones that are more properly referred when talking about Coralite, and they are found only since the introduction of celluloid in Carter production.
|11xxx||Pearl o White Pearl|
|20xxx||Black & Pearl|
The Pearltex versions (the material was introduced around 1929) adopted different number code for colors, always consistent of two digits, which is illustrated in the table on the left. The colors are: Pearl, a pearly white (also called White Pearl); Rose Petal, a pinkish color; Cerulean Blue, a turquoise blue (which can be confused with the Wave Green); Wave Green, an iridescent green; Black Pearl a black with pearl; Black & Pearl the classic black and pearl.
A special thanks to Jeff (FPN user "Jeff L") for providing such interesting information (please see the link below in the references).
-  Discussion on FPN forum