When opening certain JPG images in Photoshop, they look different (worse) than when opened in any other application. They get some kind of additional distortion/artifacts.
If you look closely at the right side of the following screenshot, you will notice that the edges between the color areas are kinda jagged (less smooth) in comparison to the left one.
When zooming in, it appears that every second pixel line at the borders of the red areas is distorted in horizontal direction:
left side: image opened with JPEGView, Windows Photo Viewer, Google Chrome or PaintShop Pro X5
right side: image opened with Photoshop CS6 (also tested on an old CS4 version - same result)
The image retains those distortions when saved from Photoshop. No matter if saved lossless (PNG) or not (JPG).
However, when opening the image with an image viewer (i.e. JPEGView), taking a screenshot and pasting it into Photoshop, there are no such artifacts. Even when then saved as JPG and reopened, there is still no distortion.
Therefore the issue must be related to the format the original files are saved in. According to the metadata stored within the JPG the image was edited with "Adobe Lightroom".
You can find the image in question here: http://farm5.staticflickr.com/4153/4998481702_82cd4a77be_o.jpg
(it happens to other related images from this photostream too)
Can anyone shed light on what's happening here?
Could eitehr be PS's cache tiling doing something weird or a hardware acceleration issue. As a test, turn off OpenGL/ OpenCL under Edit --> Preferences --> Performance and see, if it makes a difference. Also check your cache settings.
thanks for your reply!
I've tried turning off GPU acceleration completely and reopening Photoshop and the image -> same result.
Also tried various cache level and tile settings but no luck either.
Note: as mentioned in my first post I can also reproduce this on CS4 on a different machine. Therefore I doubt it's an issue with my hardware.
You can try reproducing it yourself by downloading the image linked in the last paragraph of my first post.
I've set Photoshop to ask me if there's a conflict with embedded color schemes but it doesn't ask when opening this file. So I presume it doesn't use any specific profile. (Can I check this directly somehow?)
EDIT: I've now set to ask if there is no profile embedded and Photoshop now says that the image has no embedded RGB profile.
My color profile within Photoshop is set to sRGB which is the default for my display.
When I try switching to other RGB profiles in the list, the colors change but the distortions are still there no matter which profile I choose.
Since there seems to be no trivial solution for this and I assume this is actually a bug, I reported it here: http://feedback.photoshop.com/photoshop_family/topics/photoshop_reduce s_quality_adds_distortion_when_opening_certain_jpg_files