Why does noise seem to reappear after saving a noise-reduced RAW edit as JPEG?
Asked 2/10/2014
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2 answers
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I’m editing RAW files in Photoshop and applying noise reduction. The image looks good while I’m working on the RAW file, but after I save it as JPEG, the noise seems to come back.
I know JPEG is a compressed format, but I’d like to understand what might cause this and how to avoid it during post-processing. Could this be JPEG compression artifacts, export settings, sharpening, image size, or viewing magnification? What’s the best way to keep the image clean when exporting?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
12y ago
2 Answers
4
JPEG doesn't retain 100% of the data. What you're calling "noise" in the jpeg might be what's usually called compression artifacts, or jpeg artifacts. If they're showing up when you save as a jpeg made with the maximum quality setting, the only fix is to save in a lossless format (tiff and png are popular).
I save everything in a lossless format, usually PSD. I save a jpeg version for the web, if needed, often at medium or high compression, and live with any artifacts. The only other reason I would save as jpeg is to send to a printing service that requires jpeg - if they take lossless formats I send them one of those (tiff usually).
As a side note different images can take different levels of compression without being too much impacted by the compression. Smooth gradients seem to be very susceptible to showing compression.
Originally by user14418. Source · Licensed CC BY-SA 4.0
user14418
12y ago
0
Generated from our catalog & community — verify before relying on it.
Saving as JPEG normally should not add visible "noise" by itself, especially at high quality settings. What you may be seeing is either JPEG compression artifacts or a difference caused by export/viewing settings.
Things to check:
- Use the highest JPEG quality setting and see if the problem remains.
- Compare the JPEG at the same pixel dimensions as the RAW-derived image.
- View both files at the same magnification; differences can look worse when zoomed in.
- Check whether extra sharpening is being applied during export, which can make noise or artifacts more noticeable.
If artifacts are visible even at maximum JPEG quality, use a lossless format such as PSD, TIFF, or PNG for your master file. Then create JPEG copies only when needed, such as for web use or services that require JPEG.
In short: keep your edited original in a lossless format, export JPEG only as a final delivery file, and use high-quality settings with no unintended sharpening.
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