PaperSurvey can process a wide range of image qualities, but better quality scans produce more accurate results with fewer fields flagged for manual review.
Minimum requirements
There is no strict minimum resolution that will be rejected. However, very low-quality images will result in more fields being flagged for verification, which means more manual review work for you.
Recommended resolution
300 DPI is the recommended scanning resolution. This produces clear, accurate results for both checkmarks and handwritten text.
| Resolution | Result |
|---|---|
| 300 DPI | Best results, minimal review needed |
| 200 DPI | Acceptable, some fields may need review |
| 150 DPI or below | Higher chance of recognition errors |
| Above 300 DPI | No added benefit, larger file size |
What affects quality
Beyond resolution, these factors impact recognition accuracy:
- Print quality - Surveys printed on a good laser printer produce clearer marks than inkjet prints
- Photocopies - Photocopied surveys lose some detail but are still readable. See Can Paper Surveys Be Photocopied?
- Pen choice - Black or blue pen produces the most consistent marks
- Page condition - Wrinkled, folded, or stained pages may cause issues
- Scanner cleanliness - Dust or smudges on the scanner glass appear on every page
Smartphone photos
Photos taken with a smartphone camera can also be processed, though they typically have lower quality than flatbed scans. For best results with phone photos, ensure good lighting and hold the camera directly above the page.
When quality is too low
If PaperSurvey cannot read a page at all, it will be flagged for your review. You can then manually enter the responses or re-scan the page at a higher quality.