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Export from Jpeg to Jpeg

Uffe Prebensen
hi all,

I would like to understand why an original jpeg file (from Fuji XT-3) increase file size when being exported (e.g. from 11 mb to 15mb)
I have not made any editing and I choose following parameters:
Process Recipes: JPEG sRGB
Format JPEG
Quality 100
ICC Profile SRGB Color Space Profile
Scale Fixed 100%

Thank you for the support,

Br,
Uffe
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Kommentare

8 Kommentare

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  • Ian Wilson
    Moderator
    Top Commenter
    So if you have made no changes, why are you exporting it?

    And the quality slider may have something to do with it, I suspect.

    Ian
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  • Uffe Prebensen
    Thanks Ian,
    I know it is an odd question. I am a new user and I am just experimenting with the software.
    In practical I would never need to export from jpeg to jpeg w/o having made any edits.

    However, I would like to understand how the file size can increase when quality is at 100%.
    I am fully aware I can lower the file size by reducing the quality to e.g. 92%.

    Uffe
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  • Uffe Prebensen
    anyone - please ??
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  • Ian Wilson
    Moderator
    Top Commenter
    I think that it is almost certainly to do with the quality setting. When Capture One looks at a JPG file, it has no way of knowing what compression was used on it, and what "quality %" setting was used when it was created. It just sees a rectangular block of pixels. If that is, say, 6000x4000 pixels, and you then export it at !00% quality, Capture One will create a new JPG that will be the sort of size you get from a 6000x4000 image at 100%. (That will vary a bit, depending on the exact content of the image.) It is just working on an "original" image and doesn't know how where the pixels in it came from, whether out of cameras, after compression by some other app, after upsizing by some other app, etc.

    As you know where the original file came from (Fuji X-T3, out of camera, if I understand your original post right) you could presumably check what settings were applied by the camera when it first saved the file. I gather that the XT-3 has file quality settings of Fine or Normal, and Normal uses more compression to produce a smaller file size. But once Capture One has the file it has no way of knowing where it came from or what created the pixels it sees. Do you know what setting (Fine or Normal) was used in camera?

    There is no easy way of checking what quality setting was used in creating a JPG. Googling it suggests that you can get hold of an app that may be able to estimate it, but it is not information that is saved in the file header. (And my understanding is that the quality setting varies from app to app. A JPG from Capture One at 75 setting may not have the same compression as one from some other app also at 75 setting.)

    Ian
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  • Permanently deleted user
    I am just now handling with the same problem. I generally make jpg photos in fine quality (Sony RX-100 VI). Than I edit it with C1. And I absolutely do not understand the increase of the file size when exporting it with 100% quality. I would think that the photo, imported in C1, is defined in the moment as a 100% picture and when I export with 75% quality then the quality and the size decreases. When I export with 100% quality I would expect that the size would stay roundabout the same. But it can become nearly the double size (e.g. From 7,4 MB to 13 MB).

    Or do I have to export with the same percentage compression as my camera did use? But doesn't become the quality in this way ever less?
    At last I want to export the photo without loss of quality in comparison to the original jpg photo.

    Tim
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  • Ian Wilson
    Moderator
    Top Commenter
    It would be instructive to take some photos using the RAW + JPG feature in the camera, process both the RAW and the JPG at various JPG quality settings, then compare file sizes with the out-of camera JPG, and also compare whether you can detect any visible difference between them. I get the desire to have the highest quality possible, but if you can't tell the difference between a print made from a 100% JPG and an 85% JPG, then there is no real need for the extra %age (because the file size difference between 100% and 85% JPGs is considerable. And for display on a website, a lower %age again would probably be completely adequate.

    It may well be that the JPG put out by the camera uses more compression (and so a lower file size) than you would have from a 100% JPG exported by Capture One.

    Ian
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  • Permanently deleted user
    Ian3 wrote:
    It would be instructive to take some photos using the RAW + JPG feature in the camera, process both the RAW and the JPG at various JPG quality settings, then compare file sizes with the out-of camera JPG, and also compare whether you can detect any visible difference between them.


    I will do this.

    The point is that you can see a slight difference between 100% and 85% - already with the proof function.
    I think about concentrating in future on working with the raw, what I did not do upto now, because at last I ever will save jpgs, which is sufficient for me also for prints in big sizes, what I make quite often.

    Thanks,
    Tim
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  • Uffe Prebensen
    Ian3 wrote:
    I think that it is almost certainly to do with the quality setting. When Capture One looks at a JPG file, it has no way of knowing what compression was used on it, and what "quality %" setting was used when it was created. It just sees a rectangular block of pixels. If that is, say, 6000x4000 pixels, and you then export it at !00% quality, Capture One will create a new JPG that will be the sort of size you get from a 6000x4000 image at 100%. (That will vary a bit, depending on the exact content of the image.) It is just working on an "original" image and doesn't know how where the pixels in it came from, whether out of cameras, after compression by some other app, after upsizing by some other app, etc.

    As you know where the original file came from (Fuji X-T3, out of camera, if I understand your original post right) you could presumably check what settings were applied by the camera when it first saved the file. I gather that the XT-3 has file quality settings of Fine or Normal, and Normal uses more compression to produce a smaller file size. But once Capture One has the file it has no way of knowing where it came from or what created the pixels it sees. Do you know what setting (Fine or Normal) was used in camera?

    There is no easy way of checking what quality setting was used in creating a JPG. Googling it suggests that you can get hold of an app that may be able to estimate it, but it is not information that is saved in the file header. (And my understanding is that the quality setting varies from app to app. A JPG from Capture One at 75 setting may not have the same compression as one from some other app also at 75 setting.)

    Ian


    Thank you for the support.
    I am using the extra fine jpeg setting in camera.
    I guess the camera compresses more than Capture 1 and I guess that is fine. I am ok with the fact that the file size increase after edits when keeping quality at 100%

    -Uffe
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