Throughout the printing process, minor printing imperfections may have occurred, either through the printing or the handling process. In order to ensure only the highest quality sheets move to the numbering operation, sheets are thoroughly examined using state-of-the-art computer technology.
To examine 32-subject sheets, the currency inspection section uses an Offline Currency Inspection System, otherwise known as OCIS. It integrates computers, cameras, and sophisticated software to completely analyze an untrimmed printed sheet. By examining untrimmed sheets, the BEP is better able to monitor color registration and ink density.
As the sheets pass through the system at the rate of about 8,000 sheets per hour, a transmissive camera inspects the paper by looking through the sheets to ensure the thread and portrait watermark are in the correct position. In addition, two separate cameras take a digital picture of both the front and back of the sheets, breaking the images down into four million tiny pixels. After the sheets are trimmed, a trim camera takes measurements of the sheets. All data is gathered from the sheets and compared to what is considered a perfect "golden image," and within three tenths of a second, the computer decides if the sheet is acceptable or a reject, looking for defects such as ink spots, ink deficiencies, or smears.
The 32-subject sheets are trimmed and split in half to create two 16-subject sheets. The sheets, with the exception of $100 sheets, are stacked into two piles of 10,000 good sheets while the rejected sheets are reconciled and later scheduled for destruction. Because of the addition of the 3-D security ribbon in the $100 paper, they are stacked into four piles of 5,000 good sheets. This allows the stacks to be more stable during transport.