How to stop Acrobat from compressing JPG images when opening them, and creating weird artifacts?

[mmiummiu]

So I needed to make a PDF by combining JPG image files (right click > show more options (thanks, Microsoft!) > Combine files in Acrobat; or, into Acrobat: File > Create > Combine files into a single PDF... - and this by the way crashes half the time but that's another issue).

Whatever settings I choose (chose best quality setting from Combine Files interface), Adobe Acrobat opens the JPEGs with some weird artifacts around them. As if it's compressing them the moment they are imported. 

This seems to be a problem even when I create a PDF from a single JPEG. The image quality instantly drops. 

What to do, any ideas? I can't seem to create a PDF document at all, with any resemblance of decent quality.

I've been searching for a while and I can't seem to find a solution. Attaching a particularly annoying example.

[mmiummiu]

I wanted to add that original JPG files are decent quality; I assume I would be fine if I exported from original workfile (Illustrator etc.), however I WANT to be able to create Acrobat files from JPG. This should be an option.

[MZperX]

Not a solution, just a workaround: importing images from TIF gives you the option to select various compression levels, including maximum quality JPG and losless JP2000 (Preferences > Convert to PDF > TIFF).

Be alerted, however, that Acrobat will recompress all text and non-text images in medium quality if you apply text recognition other than "searchable text (exact)".

[mmiummiu]

I didn't see these options - all I see in both routes I take (from Explorer > Combine files in Acrobat and from the Acrobat app itself: File > Create > ...) are these icons that appear in the upper part of the screen that indicate file size. I choose the larger of the three and still create a damaged looking picture with artifacts. This happens regardless if I choose to create a file from TIFF or from from JPG. 

However, I did some experiments yesterday and I arrived at weird conclusions:

I do have a bunch of similar JPG files that didn't export with artifacts. Actually, they are the same pictures, but in A4, whereas this PDF export should produce an US Letter document. Both A4 and US Letter files look similar in sizes, that is - they are JPGs exported with similar/same quality.

However, I noticed that when I try to recreate a PDF from the A4 JPG, I get a dialog in Acrobat notifying me that there's an embedded colour profile in this file. The sRGB colour profile is identical to the working space's colour profile; Acrobat asks me if I want to attach it (will increase file size). There's no embedded profile in the US Letter pictures.

Last night I was able to re-create these PDFs from the JPGs again - the A4 without the artifacts, the US Letter with the artifacts.

Today and right now I recreated a single US Letter PDF from a single JPG *without* the artifacts. I am not sure what to think of it as Acrobat is showing a few bugs now - "combine files" is missing from Windows Explorer interface and when I tried to use the > Create > option Acrobat crashed, and I don't have the time to restart my computer to try to fix Acrobat (it has done this before), but I think it something has to do with colour profiles. I should have to check this later. 

[JR Boulay]

As you can see from this capture, when it opens a JPEG file Acrobat never recompresses it.
Your issue comes from somewhere else.

Make sure that the image files are really in JPEG format.
Make sure you are not using Distiller or any other software that recompresses JPEGs.

[mmiummiu]

Yes, I've checked these options. I have actually selected "asked when opening" and that's why I started to get a dialog saying that there's an embedded sRGB profile in JPG files that produce no issues, as opposed ot the ones that produce a damage resulve, which don't have an embedded profile. 

Maybe the issue comes from the JPG files themselves, and maybe it has to do with the colour profiles. However, Acrobat keeps crashing today and until I restart and hopefully have the issue fixed I can't replicate it with and without a profile embedded.