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I have this issue with lightroom, when it adds grain / noise after exporting photo. The original picture is a lot better then processed.

And the particularly wierd thing is that often, right after export, photo looks good, but after few days, when I open it using same software, it looks very grainy. Also from time to time it switches back from grainy to good, but most often it's grainy. I belive the preview software use some noise cancelling to remove that grain, but I am not sure why it sometimes work, and other times doesn't. But with original photos, it's never grainy.

When I use noise cancelling (after sharpening) in lightroom, it's a bit less grainy, but it's still far from original.

Here is one example, but I've came up on even worse cases.

Original Original

Grainy Grainy

While, same processed photo, uploaded on flickr doesn't have grain. I guess that is some noise cancelling on the flickr's side.

Flickr enter image description here

Did anyone had similar experiences?

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    \$\begingroup\$ "After export" export as what? jpg, png, tif…? \$\endgroup\$
    – Tetsujin
    Commented May 17, 2020 at 11:15
  • \$\begingroup\$ @Tetsujin I export as jpg. \$\endgroup\$
    – Gavrilo Adamovic
    Commented May 17, 2020 at 11:24
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    \$\begingroup\$ @Jonas - red herring. No amount of jpg compression would introduce that kind of random noise. It would introduce big, square jpg blocking artefacts. \$\endgroup\$
    – Tetsujin
    Commented May 17, 2020 at 17:45
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    \$\begingroup\$ You went from color ("the original") to black and white (lightroom). Be aware that some black and white processing routines add fake grain which (supposedly) makes them look more like film. It's possible a filter is being applied and turned on and off depending on what precisely you're doing. Maybe check for this and let us know. \$\endgroup\$
    – StephenG - Help Ukraine
    Commented May 17, 2020 at 20:31
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    \$\begingroup\$ I think it's about image rendering algorithms. Probably when you see the photo at Flickr, Firefox or whichever your browser may be it's resizing/resampling the photo much better than your viewer. What I don't understand is why some days it works fine and others doesn't. Maybe caused by insufficient Ram or it's probably a bug in the viewer. \$\endgroup\$
    – Alpha-Isomethyl-Ionone
    Commented May 18, 2020 at 6:38

2 Answers 2

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There is no way I can imagine that the same jpg can one day be 'clean' & another day be 'grainy', then the next back to 'clean', unless it is being viewed by an app that is failing to correctly load it, or is re-interpreting at load.

The file itself is either good or it is broken. Broken files don't demonstrate 'grain' they either show large blocks of unmistakable error, or they will not open at all.

Test the files in another app or on another computer.

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  • \$\begingroup\$ Yes, it's realy wierd. I've updated my answer with an example, if it helps. \$\endgroup\$
    – Gavrilo Adamovic
    Commented May 17, 2020 at 14:42
  • \$\begingroup\$ The first two are not the same image. One has been processed from the other, using unknown parameters. The third doesn't look comparable to the second, not only is the third less grainy, as you state, but it appears to have a completely different contrast setting applied & a different tonal balance. \$\endgroup\$
    – Tetsujin
    Commented May 17, 2020 at 14:52
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    \$\begingroup\$ As @Tetsujin said, you are starting with a jpg, the second photo is not the same as the first. And the third was uploaded, ad if I see the magnification slider on image 2, it seems to be scaled down. If you downsample a photo, you actually get rid of the grain. So the only mystery is, what did you do to the 2nd image. \$\endgroup\$
    – Kai Mattern
    Commented May 17, 2020 at 17:08
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Noise reduction is processor-intensive and doesn't make any mathematical sense on low-resolution previews. So you don't get NR until you do something that forces a fullrez preview. After which lowrez previews get generated from the now-NR'd fullrez.

Generated fullrez previews get invalidated/deleted by any settings change. There is also a setting for how many days to keep fullrez previews.

So whether you have an NR'd fullrez to work from can come and go unexpectedly.

Exports generate a fullrez then downrez to specified size but don't usually keep said fullrez as a fullrez preview.

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