How to use the sheet
- Print it at 100% scale on the paper stock you will actually use.
- Check the bar measures 100 mm.
- Stand at the distance the real code will be scanned from and try each size. The smallest that scans first time, every time, is your minimum; go one step larger for safety.
- Try the contrast pairs under the real lighting. The inverted pair is there to show you what fails.
Common mistake
Testing on plain office paper then printing on glossy card. Gloss adds reflections that kill contrast. Test on the final stock.
Try it yourself
The test sheet is one step. The guide has the other nine, from checking the link works to what to do if the printer is offset.