Start with enough resolution
Sheet music contains thin staff lines, stems, beams, accidentals, slurs, dots, and small text. If the source is too soft or aggressively compressed, recognition has less visual information to work with.
For ordinary printed scores, 300 DPI is a useful starting point. Dense engraving, small print, faint originals, or older editions may benefit from a higher-quality source, but simply increasing DPI cannot repair blur or bad focus that is already present.
- Prefer a real scan or clean exported PDF when possible.
- Avoid screenshots that have already been resized several times.
- Do not compress the PDF so heavily that staff lines and noteheads begin to break apart.
Keep the page straight and flat
Skew changes the geometry of staff lines and can make symbols harder to place correctly. Page curvature near the spine of a bound book creates a similar problem because one system can bend across the image.
Align the page before scanning, use deskew correction when available, and flatten bound pages as much as is practical without damaging the book. If you are using a document-scanning app, check the final PDF rather than assuming automatic correction was perfect.
- Staff lines should run horizontally across the page.
- Crop away unnecessary borders while keeping the complete notation visible.
- Avoid perspective distortion where the top of the page is much narrower than the bottom.
Prioritize contrast over a pretty paper texture
Humans can read music through mild shadows, yellow paper, pencil marks, and uneven lighting. Recognition software has to separate musical symbols from the background, so those same imperfections can create false shapes or hide real ones.
A neutral, readable page with clear dark notation is usually more useful for OMR than a photograph that preserves every detail of the paper. Greyscale scans are often a practical compromise when the original is aged or lightly marked.
- Avoid deep shadows along a book gutter.
- Check that thin slurs, stems, beams, and ledger lines are still visible.
- Remove obvious blur, glare, fingers, and page-edge clutter before creating the PDF.
Review the score after recognition
No scan setting can guarantee a perfect result. Optical music recognition is a reconstruction step, not a photocopy. Dense polyphony, unusual engraving, overlapping symbols, lyrics, tuplets, and poor originals can still require correction.
After conversion, compare the digital notation with the source page. Listen when audio is available, but also inspect the notation itself because two scores can sound similar while differing in spelling, voices, markings, or layout.
- Check key and time signatures first.
- Spot-check accidentals, tuplets, ties, slurs, and multi-voice measures.
- Verify the beginning and end of every system so missing measures are caught early.