Edit jpg in photoshop creates a huge file

[francesco_g]

Lightroom Classic 14.1 on Windows 11

When I edit a photo in Photoshop choosing the option "Edit a Copy with Lightroom Adjustments" with following parameters:

• File format: JPG
• Color Space sRGB
• Bit depth: 8 bits/component
• Resolution: 240

Lightroom Classic creates a huge JPG file, more than 100 MB for a 45Mpx image (shot by Nikon Z8) or even for a 24Mpx (shot by Nikon Z6II). The file is so big that PS can't open it and gives me the error message "Photoshop could not complete your request because of a program error". I have no problem opening any other file I have.

If I use any other external editor (even Paint, but usually I use Topaz Denoise AI) with the same export parameters, the JPG file created by Lightroom Classic has the usual size of 6-8 MB and I have no problem opening in Photoshop.

[JohanElzenga]

I'm a bit puzzled about what you describe here. 'Edit a Copy with Lightroom Adjustments' is a dialog that you will only get if you edit an RGB file (jpeg, tiff, psd), not if you edit a raw file. But when you do that with Photoshop as primary editor, then you will not get another dialog where you can specify file format, color space, bit depth and resolution. This is the dialog for 'Edit in Photoshop':

The copy that opens in Photoshop will not be a jpeg, but a tiff or psd. That, including the color space and the bit depth, is specified in 'Preferences > External Editors' and jpg is not an option, only tiff or psd are. So even if your original file is a jpg, the copy could be a 16 bits TIFF, which explains the huge size. Don't be fooled by the file name that Photoshop shows, ending with .jpg. That's because the Photoshop file has not been saved yet, so you'll see the original file name, even if the image in Photoshop is 16 bits (which is not supported by jpg).

It's possible to add Photoshop as secondary editor as well. If you open an image in a secondary editor of in a plugin, then you do get a dialog with the options you mentioned. Here's how that looks for a plugin:

So did you add Photoshop as secondary editor and are you using that? If so, are you sure this link is still pointing at the most recent version of Photoshop?

[francesco_g]

Thank you for your reply, Johan.

Yes, in order to be able to edit a simple jpg in PS (and not a huge TIFF/DNG since I don't need it), I add PS as a secondary editor. And yes, I am pointing to the latest version of PS, since my PC is brand new and I started with a fresh installation of Lr/Ps/Camera RAW software.

Sorry for the missing information.

[JohanElzenga]

OK, to make sure that this is not the cause of the problem, do this. In Preferences - External Editors change the settings for Photoshop to 8 bits/color and sRGB. You can't specify JPG as file type, so use TIFF and ZIP-compression. Then try if 'Edit in Photoshop 2025' will work. If it does, then there is something wrong with the way you added the secondary editor. If you get the same problem, then there is something wrong with your Photoshop installation.

[Per Berntsen]

use TIFF and ZIP-compression

By @JohanElzenga

ZIP compression works best with 16-bit files. LZW is very effective with 8-bit, and can reduce the file size significantly, depending on image content.

[JohanElzenga]

Correct. I quickly glanced at the compression options, but forgot that I had 16 bits/color selected, so LZW wasn't an option.

[francesco_g]

"Edit in Photoshop 2025" works and always worked. But I simply don't need a TIFF nor a PSD file, because sometimes I just need little editing (like spot correction) that Lr doesn't manage well. So for me it's enough yo have a JPG file.

The way I added the secondary editor is in the image, I think that there isn't anything wrong:

and it should work like the other external editors.

I tried to delete and create a new preset, but I have the same error. But, I repeat, only with Photoshop.

Could you please try if you have the same problem with the same parameters I am using?

[JohanElzenga]

Using Photoshop 2025 as secondary editor works fine on my computer, but as I am using a Mac, that does not say much.

[francesco_g]

OK, so I have to wait for other people that have the same problem or you can raise a flag in order to deepen the issue?
Thanks!

[francesco_g]

At the moment I use "Edit on Topaz AI", close Topaz AI and then "Edit on Photoshop 2025" on the JPG, but it's not the ideal workflow ^^'

[JohanElzenga]

If you only want to make a small edit like a spot removal, then why don't you do it like this: Use 'Open in Photoshop 2025'. In the dialog, do not make a copy but use 'Edit Original'. Photoshop will open the original jpg. Make your edits and save. During your work in Photoshop you will not see the Lightroom edits, but on return in Lightroom they will still be there (and will still be non-destructive!) and your Photoshop edit will have updated the original with that spot removal.

[francesco_g]

Yes, but I must have a JPG.

So, since I usually work on RAW files, now I have first to convert them to JPG with "Edit on Topaz" and then I can use "Open in PS 2025", as I wrote before.

[JohanElzenga]

You never said you did all this starting from raw... OK, in that case using Topaz as interim is probably the best workflow for now. There is nothing to 'flag' here; Adobe reads these forums too. If others can confirm your problem then this could be a (Windows only) bug, but even then I doubt it will be high on their list of bug fixes. Using Photoshop as secondary editor to edit jpgs is a workflow that Adobe clearly does not recommend. If they thought that was a good idea, then they would have added jpg as an option for the primary editor.