Different file size when exporting with NIK or DxO

I do not understand why I get totally different file sizes when exporting jpg from PL or by exporting them from NIK. Settings for export are the same as the NEF image in question.
From PL I get abt. 1.38 MB and from NIK/Sharpener I get 281 KB only.
I used to resize the images to final use when sharpening them at the end. Now this seems not to apply any more. What do I not understand?

PL6 Elite
NIK 6 Sharpener Output
WIN 11

Sample images and their settings are available on request.

The JPEG compression rate applied depends on the publisher.
It’s not a mathematical reality :wink:
Sharpness has a major influence too.


1 Like

Those sizes seem quite low anyhow: what resolution and compression level are you using?

I have v3 of this tool and I don’t see a place to choose compression setting (not in preferences, not in save window).
Do we have choice in later versions ?

No idea, since I don’t use Nik sharpener.

But PL definitely has a compression setting when exporting, always had it, and I get much bigger file sizes (but I always export at 90-95% quality).

NIK export settings

Here are my settings and respective final image and where I find the settings for export quality in NIK.
NIK means settings and image exported thru NIK Sharpener
File means settings and image exported thru PL export to disc.

The result regarding file size is not related to this image only.

In this comparison, the sample image does not come out in original file size because the forum automatically (?) reduces quality. The size deference is as described in my first text and the image from NIK is only about one fifth (1:5) of the image size of the export straight from PL. I feel that there has been made a choice for compressing somewhere but I cannot find where.


Ok, then you have compression at 100% in both, and you export to 1920x1080 which explains the small file sizes.

Then the difference can only be explained perhaps by saying that the compression algorithm has different efficiency in the two programs even at the same 100% setting. I also see that the ppi setting is different, but that shouldn’t have any impact on file size.

It was so convenient to make an image at a specified size in pixels and MB. I even used Sharpener just for that with no sharpening at all. It all started when I up-graded to NIK 6. Next I will up-grade to PL 7 and see what happens then.

I have v3 of this tool and I don’t see a place to choose compression setting (not in preferences, not in save window).
Do we have choice in later versions ?

Did you find my answer to this?

1 Like

From your screenshots, you already have it! It’s the “quality” setting: it’s equivalent to “compression”.

Yes, the quality is set at 100 %. There should be no significant loss of resolution. Earlier experience with NIK 5 made files up to 2 MB with these settings. Now I get anything between reasonable and minor.

Hypothesis: newer versions have become more efficient. Same quality with lower file sizes.

One you have pixels set to 300PPI and the other is set to 350PPI. So that may make a difference.

IMHO, it shouldn’t. The PPI setting is only a “tag” used for displaying/printing purposes, it doesn’t have any impact on the actual content of the image.

What we see here is the result of exporting as jpeg twice

  1. raw → jpeg with PhotoLab
  2. jpeg → jpeg with Nik

Even when set to 100% exported files can loose information and therefore size.
Loosing information (aggregating pixels into areas) is one of the properties of jpeg compression.

I propose you replace jpeg by 16 bit TIFF when exporting to Nik.


Oh, yes, that would definitely explain it too. I had missed the part where the export from PL to Nik was done in JPEG rather than TIFF!

it seems it is not compression but quality. So this should be the less compressed option possible for both.

Yes, thank you.

Jpg is jpg. DxO do not write the jpg algorythm.

In which case images should not have the same size in pixel. This is not the case.

Jpeg → jpeg = loss of quality twice. Compression twice. I think you nailed it.

I don’t think so. Compression is done on the in-memory RGB image. It’s not done cumulative.
In your case it will be a problem when editing a jpg every time.
You can test it by opening a jpg in a editor or browser and than “save as”. Save as forces a new compression. Load the saved jpg again and repeat it. Doing so a few times you’ll see the file size doesn’t change that much any more.


The fact is that this issue is new and it appeared when I shifted to NIK 6. With NIK 5 the file size did not deteriorate this way and I could produce a copy to meet my requirements regarding file size and horizontal/vertical pixel count. This seems to have gone.
I do not know what image format is internally used when an image is exported to a NIK plug-in. Perhaps DxO could contribute to this conversation by clarifying this and advising how to remedy the issue.

…statement being debatable according to what I just found in a Q&D test.
Re-exporting a JPEG with DPL7 over and over again even increased the file size. The 8th generation file had 13 MB, while the source started at 12 MB.

With different settings, results will be different: files can get smaller…
Bildschirm 2023-10-06 um 19.43.19
(chroma de-noising set to max)

…and get weird effects (check at full size)