Reading
Spots that come from the lens
Marks made by the equipment land in predictable places. Once you know where they gather, you stop hunting for them and start checking three places.
Three sources, three signatures
Dust on the sensor is small, hard-edged and stubbornly repeatable. It appears at identical coordinates on every frame from that body until the sensor is cleaned, and it darkens as the aperture closes, because a narrow aperture casts a sharper shadow of the speck.
A smear on the front glass is the opposite: wide, soft, low in contrast, often in one corner, and visible mainly as a milky patch where a light source sits behind it. It moves between frames because the lens gets wiped and touched.
Anything on the subject side — rain on a window, a fingerprint on the glass of a picture frame, a hair on a scanner bed — sits in the picture's own focus plane and has its own sharp edges. It is the easiest of the three to lift, because it is genuinely a small object on a background rather than a shadow across everything.
Where to look
- Any wide even field: sky, a painted wall, a sheet of paper, still water. Marks are invisible against detail and obvious against nothing.
- The upper third of a landscape frame, which is usually the largest area of flat tone.
- The same coordinates you found a mark in last time, on this camera.
- Frames shot at a narrow aperture, where sensor shadows are hardest.
Look at full size rather than fitted to a window. A fitted view throws away most of the pixels and most of the specks with them.
Marks that belong to a different page
Everything above is about a file that came out of a digital camera or a phone. A mark on a scanned print is a different subject with a different history — damage to the paper rather than a shadow in the optics — and repairimage.com is the domain that owns it.
The distinction matters in practice. Optical marks are isolated and round. Damage on paper runs in lines, gathers along folds and corners, and usually arrives in quantity, which puts it well past a ceiling of six.
A working order
- Open one frame from the card and look at the flattest area in it.
- Tap each mark once and read the numbered tags.
- Note where the tags landed. Those coordinates will repeat on the rest of the card.
- If the count reaches six on a single frame, clean the sensor rather than the file.