The 1893 233a 4c Columbian error of color was caused by the printers using the wrong type of ink. Instead of using the ultramarine colored ink the printers accidentally used the ink that was probably meant for the one cent design! I frequently notice regular #233s being offered as #223a at online auction. You must remember that some regular 233s are dark and have a slightly blue appearance. However, nothing comes close to the true error of color. If the stamp you are viewing is not the same color as, or darker than the one cent Columbian issue, it can not even be considered as the color error. This stamp should NEVER be bought or sold without certification from a trusted source! Shown below is a regular #233.

       Shown below is a couple of certified examples of the #233a error of color.

I spend my time and write these guides to help the philatelic community. I feel that my guides can help both buyers and sellers properly identify certain issues that I notice have been often misrepresented at online auction. Even If you personally already are familiar with the information presented in this guide please vote “yes” for helpfulness as it allows me to know that people support my effort to help the philatelic community . I would appreciate any emails with questions or comments on how to better help with any of my guides. If anyone is considering buying a stamp that is mentioned in any of my guides and have doubts about authenticity please email me and I will be glad to help Best regards, Mike