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Watch for non-square screengrab pixels in Photoshop CS Desktop
Screen captures in Panther may appear blurred because they have non-square pixels. If you take a screen capture with Shift-Command-3 or Shift-Command-4, then open the PDF screen capture file in Photoshop CS, it will have a pixel aspect ratio of a tad more than 1, and your image will be slightly blurred unless you turn off Pixel Aspect Ratio Correction. Don't open these files in Photoshop 7 or earlier, as there's no option for correcting the pixel aspect ratio and they'll go soft-focus. Also, don't copy a screen capture to the clipboard (e.g., Shift-Command-Control-4), then paste it into Photoshop, because Photoshop will re-rasterize and blur the image (I presume the clipboard file format is PDF).

For sharp screen captures in Panther, you could also use the Grab utility. Unfortunately, it's more hassle than the direct-to-the-clipboard method that worked properly in Jaguar, but at least there are workarounds for this bug.

[robg adds: I don't have Photoshop CS, just Photoshop Elements 2.0, and I don't think this bug is Panther-related ... or if it is, it's not obvious in Elements. I took a number of shots: (1) Direct to clipboard, (2) via Drag, (3) Using SnapzPro (saved as PDF), (4) Shift-Command-3. I then put all four images on top of one another in Elements, and the various widgets seem to line up perfectly, and nothing looks blurry -- here's my .psd file, if anyone wants to take a look [369KB download]. So either they're all 'blurred' the same amount, and I'm just not seeing it, or they're all fine ... anyone have any more info on this possible glitch?]
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Watch for non-square screengrab pixels in Photoshop CS | 13 comments | Create New Account
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10.3: Be aware of non-square pixels in screen captures
Authored by: pmbuko on Feb 11, '04 12:39:46PM

I don't know what the origianl poster is talking about. I just took a number of screenshots (both to file and to clipboard) that each included smoothed text, non-smoothed text, and images. I opened them or pasted them all in Photoshop 7 and did not experience any soft-focus or re-rasterization whatsoever. In fact, I could not tell the difference between the the screen image and the captured image.

I don't doubt that the OP is experiencing the problem as described, but I have no idea what could be causing it.

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10.3: Be aware of non-square pixels in screen captures
Authored by: julesstoop on Feb 11, '04 02:12:53PM

Maybe he/she is running the screen in a non pure ratio mode like 1280*1024 (instead of 1280*960)? And somewhere the OS attaches a dpi value to the screendump, which is 'respected' by photoshop. The app then has no choice but to re-rasterize the picture.

Just my 2 cents...

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10.3: Be aware of non-square pixels in screen captures
Authored by: _merlin on Feb 15, '04 08:39:37AM

1280x1024 actually is the correct aspect ratio for some monitors. I have a Sony FD Trinitron with a 5/4 ratio, rather than the more common 4/3. If I use 1280x960, everything looks stretched.

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Photoshop bug?
Authored by: paulrob on Feb 11, '04 02:29:08PM

No probs with viewing screen captures in PE 2, Preview or a viewer of my own.

QT and Quartz are pretty mature technologies, and a bug like this would have appeared awhile ago surely. Photoshop CS on the other hand can play with non-square pixels, and is new. Perhaps its playing with the pixels even when it's not told to.

Also what about 3rd party video card/memory?

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Authored by: paulrob on Feb 13, '04 01:47:56PM

Might have to take back some of my previous comment. Have just taken some dodgy pictures of the screen in snapshot mode. But the dodgy pictures arose because I was still in Expose mode. PDFs viewed with Preview showed loss of resolution much as the original poster described. Maybe that's the prob.

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10.3: Non-square Shots? No.
Authored by: rayola on Feb 11, '04 05:30:24PM

No, this poster is just plain wrong, at least about Apple being at fault. One of the new features of Photoshop CS is support for non-squre pixels, for working with the 1.1 pixel ratio of MiniDV and such formats. It's meant for broadcast. Sometimes, but not always, (haven't figured out exactly why it only happens sometimes) Photoshop CS will open your screen grabs with the non-square pixel preset turned on. Which I consider quite a misfeature, because obviously your screen uses square pixels. Unless you've still got a Lisa going...

Hopefully Adobe will fix this in a PS CS updater, cause it gets a little annoying. You can go to Image > Pixel Ratio > Square to correct the problem if it's happening to you.

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Watch for non-square screengrab pixels in Photoshop CS
Authored by: abacsalmasi on Feb 11, '04 06:50:51PM

Perhaps this may be the problem. Photoshop only anti-alias's images when viewed at certain percentages (100, 50, 25, 12.5) so if an images is being viewed at different ones your images will look choppy or blurry. Hope this helps.

My eyes, my eyes, these goggles do nothing!

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Watch for non-square screengrab pixels in Photoshop CS
Authored by: mjcorn on Feb 12, '04 10:22:58AM

I have had this same problem when grabbing screens on my G5 and then opening the pdfs on my powerbook. All using Panther and Photoshop CS. Although, it is not so much of a problem as a interesting thing.

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Watch for non-square screengrab pixels in Photoshop CS
Authored by: wOOge on Feb 13, '04 11:44:15AM

this is interesting, however i've never seen or encountered this problem.

it is possible they are viewing the screen shot at a reduced/increased magnification, as mentioned above.



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Watch for non-square screengrab pixels in Photoshop CS
Authored by: Kutuki- on Feb 18, '04 04:15:54PM

This might have something to do with the way Photoshop translates "points per inch" of "pixels per inch". Normaly 72 points = 72 pixels = 1 inch. But in publishing-business 1 inch = 72,27 points.
I came to this conclusion after I had to work on some MS Windows screenshot for a manual. They always opened with a resolution of 71.999 ppi.
In the Photoshop 7 preferences you can choose how Photoshop treats the unit "points per inch".

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Watch for non-square screengrab pixels in Photoshop CS
Authored by: maytey on Apr 05, '05 08:16:34PM

I am having the same problem, ever since switching to a different computer with Photoshop CS. The problem only seems to be intermittent though, which is really strange. One way I think I've been able to get around it is opening the screengrabs in ImageReady rather than Photoshop - unless it's just that I'm not getting the dialog box. Very frustrating, it used to be so easy, and Grab is a hassle to use.

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Watch for non-square screengrab pixels in Photoshop CS
Authored by: maytey on Jun 27, '06 05:14:18PM

OK, so now I'm still on the same computer, still using Photoshop CS, but having now upgraded to Tiger the problem is now even worse. Blurry text and also a new problem: when I trim a succession of screengrabs (eg when making backup gifs for a banner) the image trim function is erratic. Doesn't trim exactly to the edge. Which seems to imply that perhaps the edges are blurry too. Always viewing the image at 100% magnification. 1680x1050 screen res.

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It's a CS bug, not a screencapture bug...
Authored by: 6502 on Jun 29, '06 07:28:48AM

CS does this to me in about 1 out of every 100 or so images that I open with it (which is quite a lot of images as I use CS every day).

It opens the image as if it were NTSC instead of square pixels.

It totally wigged me out when I saw it, but I quickly realized what was going wrong.

It's easily corrected just by changing the display option, but it's still an INCREDIBLY annoying bug.

And it does it to me with both TIFF and JPEG files.

I haven't upgraded to CS2, nor have I polled others about this particular bug so I don't know whether they've fixed it.

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