The marking quality is excellent when the color contrast between the PCB and the barcode pattern is high.
If the PCB with a dark background and the barcode with a bright pattern is made, the contrast is clear and the scan rate is good.

Standard scanners use RED LEDs as lighting.

The red PCB strongly reflects the red LED, so the brightness difference between the barcode and the PCB color is reduced, resulting in a lower scan rate.
Therefore, it is very important to share the colors of the boards that are going to be used at the customer’s site in advance, to check the scan rate.