What causes vertical banding in black-and-white photo scans, and how can I fix it?
Asked 8/22/2013
6 views
2 answers
0
I’m digitizing black-and-white prints with an older CanoScan FB630U using VueScan on Mac OS X, scanning at 600 dpi to TIFF. Some scans show noticeable banding running in the same direction as the scan head moves, while other photos scanned with the same settings look fine. I’ve cleaned the scanner glass externally, but the issue remains. What typically causes this kind of banding, and what can I do to reduce or eliminate it?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
12y ago
2 Answers
6
Such banding is not uncommon, you have a a few choices on how to proceed.
Option 1: try and fix the root cause of the problem -- the scanner.
Odds are there is a (very small) bit of dust on the scan head, try opening up the scanner and using a rocket blower or similar along the scan sensor. Of course this involves opening the thing up and depending on you and your experience this may not be something you want to try.
Option 2: fix it in post
Scan a completely black sheet of paper (or better yet get a print of an image of the same size and finish as the photos you are scanning filled with the black point from one of the photos). Bring both scans into photoshop with the "black scan" as a layer on top of the original. Change the blending mode to overlay (also try linear burn and soft light) and adjust the opacity down until the banding disappears. You will probably have to push up the contrast after as this will flatten the look.
Option 3: pick up a new scanner :-)
Originally by user20982. Source · Licensed CC BY-SA 4.0
user20982
12y ago
0
Generated from our catalog & community — verify before relying on it.
This kind of banding usually comes from the scanner, not the photo. Common causes are:
- dust or debris on the scan head/sensor inside the unit
- calibration drift between the scanner’s sensor elements
- uneven scan-head movement from dirty rails, dried lubricant, or age
Why it only shows on some images: uniform tones and smooth areas make banding much easier to see, while busy textures can hide it.
What to try:
- Run any scanner calibration or maintenance routine available for the CanoScan/VueScan.
- If you’re comfortable opening the scanner, carefully clean inside with a blower; internal dust on the sensor path can cause lines.
- If the mechanism is sticking, the scan head may need cleaning/service.
- As a workaround, correct it in post: make a scan of a uniformly dark sheet/target and use it as a correction layer to reduce the bands.
Given the scanner’s age, recalibration or internal cleaning is the most likely fix. If the transport mechanism is worn or sticking, repair may be difficult and replacement may be the practical option.
Recommended products
UniqueBot
AI12y ago
Your Answer
Related Questions
Why is my flatbed scanner adding vertical lines to every scan?
Why do halftone scans from printed books show moiré lines, and how can I reduce them?
Why does my Epson Perfection V370 show vertical color bands in scans?
Why do some black-and-white film scans show harsh edge artifacts with Digital ICE enabled?
Why don’t two 180°-rotated flatbed scans align perfectly across the page?