Resizing = jaggies

Here is a bit of an odd one. When I convert my RAW files in DPP from my XSi, I sometimes resize then to 3888x2592, which is about the same size as a 10 MP camera. However when I view them in Vista's Windows Photo Gallery at fit to window size there are jaggies on bright edges but when I convert the same RAW file but with no resizing keeping it at 4272x2848 then jaggies are gone or not nearly as pronounced when viewing in Windows Photo Gallery, any ideas why this is? In both cases, I set sharpness to 3 in DPP. By the way when I view the resized image at 100% there are no jaggies.

Is this normal or is there something I can do to resolve this?

Thanks

Whenever I sharpen in DPP I end up ditching the result. Even at 3, its far too severe for me.

If you are planning to print, then the "jaggies" you see probably don't matter, but for posting online you need much more gentle sharpening procedures.

Why resize? Unless posting, when 10MP is much too large, leave it at the original size. Cropping can be done without resizing.

What JPEG compression setting are you using during the conversion from RAW? And are you using the same setting for both resized pics?

One thing to bear in mind is that when you use external software to "shrink" an image to view, you are at the mercy of that software. We see this a lot when people upload a large-sized image to a Web host and are dismayed when that host resizes the image to a normal viewing size with sometimes not-so-great results.

In general, if you want to convert an image for either Web viewing or personal viewing/emailing, you'll get better results if you do the resizing yourself -- say to a medium size like 800x600 (or you could use the POTN max for a larger image of 1024px at the longest dimension.

Try that and see if the "jaggies" don't disappear. For sure, if you don't see them in DPP at various viewing size you can blame it on the viewer!

Problem is most likely your viewing software.

Cheers everyone, when resizing I have been using the same compression setting for both sizes (Highest Quality JPEG). I think from now on I'll keep them at the original size. I was down sizing to save on disk space but to be honest I probably wont really be saving that much.

tim wrote in post #10746543
Problem is most likely your viewing software.

Bingo, and the zoom ratio used:

match14 wrote in post #10745525
However when I view them in Vista's Windows Photo Gallery at fit to window size

Compare sharpness at 100%

Ok thanks. Is there any reason why the 4272x2848 image looks better at fit to screen in Windows Photo Gallery than 3888x2592 at fit to screen in the same software? Just trying to get my head round this. Also am I better of saving my jpegs at 4272x2848 rather than downsizing to 3888x2592?

BTW way I have check and the pictures all look better in DPP rather than Windows Photo Gallery.

match14,

It's always better to save at the highest resolution you can get, so save your files at the full "native" pixel size rather than downsizing. Any downsizing is basically throwing detail away.

Ok that makes sense thanks

match14 wrote in post #10749883
Ok thanks. Is there any reason why the 4272x2848 image looks better at fit to screen in Windows Photo Gallery than 3888x2592 at fit to screen in the same software? Just trying to get my head round this. Also am I better of saving my jpegs at 4272x2848 rather than downsizing to 3888x2592?

It will just be luck of how the interpolation software works with your screen resolution.