What causes blotchy or dotted patterns in Portra 400 scans from 120 film?
Asked 6/18/2023
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2 answers
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I shot Portra 400 in a Fuji GW690/GW490 and scanned the developed 120 negatives on an Epson V600 using Epson Scan at 48-bit TIFF. In some smooth or out-of-focus areas, the scans show a blotchy/splotchy pattern of lighter dots that looks different from normal film grain. Other rolls scanned fine. What is the likely cause, and how can I check whether it came from the film, processing, or scanning?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
3y ago
2 Answers
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The diffuse dot patterns look like emulsion reticulation. It is damage to the emulsion usually caused by heat during development, but can also be an artifact of old film.
They don't look like scanner artifacts because the dust and hairs on the scan are perfectly sharp.
Have you looked at the original with at least a 20x loupe? Reticulation would be evident at that magnification.
If you can see something through the loupe, you can try cleaning the emulsion with PEC-12 and re-scanning. It's unlikely to be dirt from the looks of it, but you never know.
Originally by user106382. Source · Licensed CC BY-SA 4.0
user106382
2y ago
0
Generated from our catalog & community — verify before relying on it.
This is most likely a film-side problem, not a scanner artifact. Based on the pattern described, the two most plausible causes are:
- Emulsion reticulation — damage to the emulsion, often from heat or processing issues, and sometimes associated with old film.
- Backing paper mottling — a known 120-film issue where heat, humidity, condensation, poor storage, or expired film lets material from the backing paper affect the film.
Because dust and hairs appear sharply in the scan, the scanner itself is less likely to be creating the blotchy pattern.
To confirm, inspect the negative with a strong loupe (around 20x). If the pattern is visible on the film, it came from the negative rather than the scan. If you see residue on the emulsion side, careful cleaning and rescanning may help, but if it’s true reticulation or backing-paper damage, it usually cannot be fully fixed.
So the likely causes are film age/storage or processing conditions, rather than Epson V600 scanning settings.
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