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10.4: About Preview and rotated/mirrored images
Authored by: rhowell on Dec 07, '05 07:39:06AM

In Preview, save the rotated JPEG file in a nondestructive format, like PNG. The pixels will be rotated, and there will be no loss of quality. Then save the PNG file as JPEG if you need higher (lossy) compression.

PNG is nondestructive, right? Please correct me if I'm wrong.

Apple should have ALL of its apps be EXIF-aware.



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10.4: TIFF is nondestructive
Authored by: mclbruce on Dec 07, '05 08:49:14AM

TIFF is a safer choice than PNG. PNG does use lossy compression.



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10.4: TIFF is nondestructive
Authored by: jctull on Dec 07, '05 09:00:23AM
According to this link, png is lossless.

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10.4: TIFF is nondestructive
Authored by: fredshome on Dec 07, '05 09:02:33AM

Actually it doesn't. PNG *always* uses lossless compression and has a much simpler specification than TIFF since it can't be used as a container for all kinds of weird things (although current Tiff libs got better at handling weird file nowadays). So PNG is usually a much better choice especially when portability is a factor.

The caveat is that some apps apparently still can't read PNGs (in Windows it seems, don't know about the Mac since I don't typically manipulate images on either of those systems). But then lots of apps can't read Tiff either... Of course that's probably not a factor in the current case :)



---
Fred in Paris.



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10.4: About Preview and rotated/mirrored images
Authored by: jacobolus on Dec 08, '05 06:55:29AM

Unfortunately PNG and TIFF are much larger file formats than jpg, which is compressed. To get back to jpg after going through one of these formats would require losing data through re-compression.



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