L, M, Q, and H
L
Compact
The smallest recovery allowance. Useful when keeping the pattern compact is the priority.
M
Balanced
A practical default for many clean, ordinary prints.
Q
Resilient
More recovery for tougher surfaces or handling, with a denser pattern.
H
Strongest
The highest recovery allowance and usually the densest visual result.
How to choose
Start with M, then move higher if the code will be exposed to dirt, wear, glare, or a less controlled scanning environment. If the content is long, higher correction can increase density, so test the actual output rather than choosing H automatically.
Error correction does not replace contrast, quiet-zone space, or a real scan test. Treat it as one part of the print decision.
Pair correction with a scan test
- Generate one sample at the final output size.
- Print or place it where it will actually be used.
- Try the expected scanning distance and lighting.
- Choose the lowest level that meets the real requirement.