Dating Candy Wrappers with UPC Barcodes
UPC (Universal Product Code) barcodes were first established in the mid 1970s and not all companies started using barcodes the same year; so dating wrappers by the barcode is hit and miss for the 1970s. By 1977 there were less than 200 barcode scanners in grocery stores, but by 1980 8,000 stores were converting per year.
You may notice that there are two length sizes of UPC codes but in general they both are the same; it’s just so the manufacture can fit them on any size product. So this can’t be used as a way to date wrappers.
In the beginning it seems that not all UPCs had a checksum (or check digit) until later; maybe around 1988 or so. The checksum is the last number on the right all by itself. It’s used to verify that what is scanned in is accurate. It accomplishes this by basically adding all the digits in the odd number places and dividing it by 3 and if that number equals the checksum then it’s right.
So if the wrapper doesn’t have a UPC on it then it could be pre-1980ish and if it has a UPC but no checksum it is pre-1989ish. Remember it’s not an accurate way to date a wrapper but it can get you in the ball park.
No Comments »
No comments yet.