Loss of image quality when importing and exporting in Lightroom for the purpose of metadata only

[abdul1]

Hello,

I have a bunch of jpeg images that need to be imported into Lightroom for the sole purpose of adding metadata and keywording.

These images will then be exported back to jpegs with no other adjustments.

My first question is;

Will the images lose quality as no actual adjustments are being made to the image itself or are the processes of decompression and recompression to and from jpeg will inevitably lead to a reduction in quality anyway?

My second question is;

If there is a reduction, how noticeable will it be?

The images are currently on a MicroStock site and I need to upload them onto other MicroStock Sites but as the metadata does not contain captions, titles, and keywords, it makes sense for me to import them into Lightroom to populate this data and then export to be uploaded.

As you can see, I can't afford to lose quality and as I don't know the answer, any help will be very appreciated.

Regards

Abdul

[Just Shoot Me]

There should not be a nedd to Export those images. Changes made to Metadata can be saved directly to the original JPG by doing a Ctrl + s (Metadata menu "Save Metadata to File").

Loss of quality is based on youre Export Settings. In your case you do not need to export those files so there should not be any loss in image quality.

[dj_paige]

Use the Lightroom Classic menu command Metadata->Write Metadata to Files instead of exporting.

My second question is;

If there is a reduction, how noticeable will it be?

The images are currently on a MicroStock site and I need to upload them onto other MicroStock Sites but as the metadata does not contain captions, titles, and keywords, it makes sense for me to import them into Lightroom to populate this data and then export to be uploaded.

As you can see, I can't afford to lose quality and as I don't know the answer, any help will be very appreciated.

The way to determine the amount of loss of quality is to try it and then LOOK AT the results. Only YOU can determine if the quality meets your needs.

On an somewhat academic basis, you might want to read An Analysis of Lightroom JPEG Export Quality Settings

[gary_sc]

One other alternative is to use Adobe Bridge. From there you can access all of the Metadata options and never do anything to the image(s) other than select them, open the Metadata window (Control/Command-i), enter what you want for the image(s), and then close the window. The big negative is that you cannot change the image selection(s) with the Metadata window open so it may be a bit slower than you'd like but it will not touch the image quality.

Good luck!

[ManiacJoe]

Lots of good advice already.

To answer the question asked, yes, if you do a read-write sequence to a JPG enough times you will eventually see the data degradation. Your choice of "quality" settings in the export/write command will govern the quickness of the data loss.

[gary_sc]

After seeing all of these comments I did a plain and simple test, Here's the way to do it:

When you import, -> Add <- the images into Lightroom from wherever they are, do NOT MOVE them into another folder.

Assign keywords as you wish, then Select them all and then do a Command/Control-s. This will save the metadata to the image.

Finally, go back to your orignal foder in Finder/Explorer and do what you want with the image. 

And finally finally, in Lightroom delete the images from your catalog since you will not be doing anything with them in Lightroom at this point.

Do NOT Export them out of LR. If you do, you will be doing one of the jpging a jpg issues that are talked about above. Saving the metadata to a file does NOT change the pixels, it just adds the metadata to the file. Two different things.

Good luck!

[GoldingD]

Or, you could do your metadata edits outside off post processing software via metadata editors

https://www.geckoandfly.com/7987/how-to-change-exif-data-date-and-camera-properties-with-free-editor...

[barte84297983]

I have the same question, and it wasn't anwered on this thread.

If I import JPGs into lightroom, then export them out at 100% quality as JPGS, will I see any degredation in the newly outputted JPGs?

[gary_sc]

Hi Barte,

Interesting question, I have never thought about that.

I'm confident that it would not cause any degradation to the image. The reason is that you haven't DONE anything to the image that would cause it to resave. If you made a change to the image such as size, image quality, etc., that would cause a resaving of the data which might cause degradation. But when just exporting an image that exists within the catalog, there is no change in the image.

Keep in mind though that the image is likely to change its storage size IF you export it with a different amount of compression than you did when first saved. Let's say you originally compressed the image at (say) 70%, imported it into LRC, and then exported the image at 100%. The image will be larger than originally. If you took the same image and Exported it now at 60%, it would be smaller than the original. At that point, there may be degradation. Lastly, if you exported the same original image at 70%, it will export at the same size.

One last thought: if you only wish to have access to the same image with no changes to it whatsoever, another option would be to right-click on the image and look for "Show in Finder/Explorer." From there you can copy or duplicate-drag the file to another location on your hard drive, and it will be the exact image you have in LRC but without any changes, you may have (or have not) done.

[Conrad C]

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@barte84297983 wrote:

If I import JPGs into lightroom, then export them out at 100% quality as JPGS, will I see any degredation in the newly outputted JPGs?

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Will you will literally see any degradation, my guess is no, you won’t see any degradation.

But my understanding of JPEG compression is that it is always lossy, so if you export at 100%, that does not mean lossless (no quality loss). It means re-compress using very little quality loss, but the quality loss will be there. It may not be visible to the human eye after one re-save, but over time the errors should build up until they are visible.

Adobe has a web page explaining the difference between JPEG and JPEG2000: If you want lossless compression in JPEG, use JPEG2000, because regular JPEG doesn’t offer that.

That’s a big reason many of the earlier posts say (and I agree with them) that if you only want to change the metadata and not the image, just use Lightroom Classic or Adobe Bridge to save metadata changes only. That writes them into the JPEG file header, not the image data, so the image quality has no chance of changing or degrading.