Film fog is unwanted density that sits underneath the image, reducing contrast and making scans look grey, muddy or grainy.
Why Is There Fog Across My Film? — Berlin Photo Studio
Fog can affect the whole roll evenly or appear as local bands and patches. It is not the same as normal grain or a simple colour cast.
What the evidence can tell you
Compare the image area, frame gaps and film edges. Uniform density outside the photographs suggests a roll-wide influence; local streaks suggest light entry or handling.
Common causes
Expired or badly stored film
Heat exposure
Airport X-ray or CT scanning
A camera or cassette light leak
Accidental opening before development
Chemical fog or contaminated processing
Long-term background radiation
What can be done
Contrast and black points can sometimes improve the scan, but editing cannot fully restore separation lost beneath heavy fog. Prevention and correct storage matter most.
What to do next
Keep the negatives and inspect them under a clean light source.
Check whether the pattern affects one frame, several frames or the whole roll.
Compare another roll from the same camera when possible.
Send the laboratory the frame numbers and a photograph of the physical strip.
Frequently asked questions
Can rescanning solve the problem?
A different conversion may improve presentation, but it cannot remove physical base fog from the negative.
Does this automatically mean the laboratory made a mistake?
No. The pattern on the negative must be compared with camera behaviour, exposure, storage, development and scanning before assigning a cause.
Should I keep using the camera?
If fog forms repeated bands or edge patterns on fresh film, inspect the camera seals and cassette chamber.
Why should I keep the negative?
The negative is the original evidence. A digital scan alone cannot always reveal where a fault began.
