Lightroom will not export jpgs with requested compression levels

[Atkins Lab]

I have had this error for about 6 months. Have reinstalled and upgraded the software still no change. I set the export jpg compression level to 7 and it exports it as level 12. Have to then resave in photoshop.

Am doing this dozens of times a day. Driving me mad.

Only way I can get smaller files is the with restrict file size option, god know what's that doing. All I want is web compressed files. This should be easy.

[DdeGannes]

Could you post a screen capture of the export dialog settings you are using to create the image you require.

[Atkins Lab]

[DdeGannes]

@Atkins Lab , Thanks for the info the things that affect the file size are the Quality setting "70" and the pixels on the long size "1600". You should uncheck the Don't Enlarge option.

Just my thoughts.

[Atkins Lab]

When I open the files in photoshop, save as opens with a prompt for level 12 jpg, I select level 7 and the file size is drastically smaller after saving down in Photoshop. It's not exporting them out as level 7.

[Conrad_C]

Another aspect of this is that you can never really just save back to the same JPEG. Because JPEG uses lossy compression, the file is going to degrade slightly even if you save using the same JPEG compression level. So even if Lightroom Classic and Photoshop used the same scale and you set it to the same level and didn’t edit the image, there is no guarantee that the new JPEG file will be the same file size and appearance.

From that point of view, it almost doesn’t matter if the default JPEG compression level in Photoshop is different than the level that was in the file when Photoshop opened it.

I just did a test. I exported JPEG images from Lightroom Classic at different levels of JPEG quality, opened both in Photoshop, and chose JPEG from File > Save a Copy. Even though they were exported with different JPEG quality levels, Photoshop defaulted to 12 for both, even if I changed it and saved. So it looks like Photoshop will always default to 12 for JPEG from File > Save As or Save a Copy.

But those are not the only ways to get a JPEG out of Photoshop. You can also export a JPEG file using File > Export > Export As, and File > Export > Save for Web (Legacy).

File > Export As seems to default to 6 regardless of the starting quality or what you set last time.

But File > Export > Save for Web (Legacy) remembers the last settings, so if you export your JPEG that way and change the quality level, it will remember it for next time. And, you can save a preset of the format settings. However, because this command is intended for web/mobile, it will not retain all metadata such as ppi resolution for print.

[Per Berntsen]

The quality scales are different in Lightroom Classic and Photoshop.

LrC uses a scale from 0 to 100, PS uses a scale from 1 to 12.

You have set quality to 70 in LrC, which is not the same as 7 in PS.

See the correct answer by @Todd Shaner here:

https://community.adobe.com/t5/lightroom-classic-discussions/equivalent-jpeg-compression-settings-w-...

[TheDigitalDog]

See: 

http://regex.info/blog/lightroom-goodies/jpeg-quality

[Jao vdL]

Per already gave the answer. In addition, one thing to be very wary of is that by default Lightroom saves all your edits including masks in the metadata section of your jpeg export. This can balloon the filesize. If you're watching your filesize carefully and do a lot of edits in Lightroom to your images, make sure to select "Copyright and contact info only" in the export panel. Another thing to realize is that the scaling algorithm used in Photoshop is very different from what Lightroom does. To get similar sharpness in the final result when you scale down significantly, you should enable output sharpening at medium or high level. Photoshop uses bicubic sharper when scaling down which doesn't generally need output sharpening. Doing both those things and realizing that the compression scale in Photoshop is not the same, you should get pretty close to the same filesize and quality. 

P.S. When you save as in Photoshop on a jpeg, the number you see by default has NOTHING to do with the actual compression factor the orginal was saved as.

[DdeGannes]

@Jao vdL , I do not under your comment, "Lightroom saves all your edits including masks in the metadata section of your jpeg export."

Surely when you do an export from LrC to create a .jpeg image you will get a completely new image with all your edits applied.
If you were exporting "original" image, what you state should happen.

[Jao vdL]

You would expect that, but Lightroom includes all the xmp metadata needed for editing the original raw file in the exported jpegs. It is quite amazing. You can see exactly what edits people did for exported images you see online. Just open up an exported jpeg in Photoshop and do a file info and look for Raw Data. You will see xmp metadata for every single edit your did including info on masks you made and much more. You can actually copy all of it and turn it into a preset again that will work. So yeah if you are protective of your editing recipes, you should make sure to exclude the camera raw info when exporting jpegs.

[DdeGannes]

Ok, thanks for that info. So one would control the metadata at export. See the screen capture.

Just a thought so you share a jpeg with All Metadata, so what use would that Raw data be for someone if they did not have access to the original RAW image.

[Jao vdL]

The camera raw metadata typically adds 20kB to the file size. If you're exporting small images that is substantial. Apart from that you can look at this data and see how you edited an image. A number of people are very protective of their editing style and this just gives you everything you need to know about how they accomplished their look. You can even copy and paste it all and turn it into a preset. I don't really care much about it as I even do classes on editing and show people how I edit but I know some people are very protective of their personal style while probably not realizing all this info is written into every file they export.