Sometimes I have two coins of the same type and I reduce them to one by passing along the second. But, sometimes they have differences which make them both worth keeping. These four are all of Constantine with the same basic reverse type. I admit they are from different mints and maybe that makes them different enough to keep, but it is their different colors that makes me keep them all. Constantine, RIC Siscia 214. Sea-foam green patina. PROVIDENTIAE AVGG, "campgate" or city gate. Constantine, RIC Lugdunum 225. Dark green patina. Constantine, RIC Alexandria 34B. Lovely rust color. Constantine, RIC Antioch 81. Nearly full silvering. Show us two or more coins you have that you regard as of the same type, but you are keeping both because they look different.
Lovely patinas on those examples, @Valentinian ! Here are two examples of the same coin I keep because the artistry is so different between them in the way Pietas is rendered on the reverse. Moreover, their die-axis are 180 degrees different. Lastly, one is a dupondius and the other might be an as or dupondius -- I can't tell.
Not long ago I decided that I did not need to collect late Romans different only by officina and even got rid of some that were different by mints but don't see myself doing that again since selling lower grade duplicates is not worth the effort. In my specialty of Septimius Severus, I have several duplicates to RIC number but where the die is interesting to me in some way. No one collects common coins like denarii by die ID unless they are really into that particular series. Really! Below are three coins of Septimius Severus (many of you want only one at most). All are Legionary denarii (few of you see the need for more than one). All are Legion XXII but the dies differ in the way they filled the space on the reverse with the short legend LEG XXII. LE GXX II L E G X X I I more or less evenly spaced L E G X X I I but not spread as much Most legions in this series use a modifier (ITAL, AVG, ADIVT etc.) with the number and there are more scarce coins of LEG XXII that add on PRI but that difference causes a change in RIC number so most people who collect the series want two coins with and without PRI. The PRI Coins, to the best of my knowledge, used two obverse and three reverse dies. I only have one obverse and two reverses but will correct that when I can. I have never considered collecting by color but do have coins that differ in different ways that are of different colors. If I had the OP set, I would not consider them all the same because of the different mints. Color is a bonus.
