Our cold glass technology uses a tape which is ablatively imaged either (a) off-site
with sequential numbers or (b) on-site with a laser in the customer's plant. 

The imaged tape pattern is then transferred onto the cold (ambient temperature) glass which is stopped for approximately 2 sec. . After transfer , the mark is waterproof and will endure handling. After the first lehr pass ( ~ 300 deg. C) , the mark becomes hard and scratch resistant. 

This method has several advantages: 

1. It produces a mark which will not flake or cause apature blockage. 
2. It is low in cost when compared to "ceramic labels" 
3. It is fast. 


Pictured here is the resultant cold glass marking before a lehr. Note that the barcode is a "negative" Code 128C symbology wherein the bars are white and the background is black. Many (inexpensive) commercial bar code scanners can be setup to read the negative image.