Does rotating an image several times affect the quality?

Question

I'm using a template for a cd sleeve. One half of it is upside down so to work on the other half I have to rotate the image. I will have to rotate the image a hundred times before the project is finished.
Does this affect the quality? If so, any workarounds for me?
Thank you.

Answer 1

As the previous poster said - use non-destructive transform methods wherever you can. Apart from that, note, that rotating in multiples of 90 degrees does not change the pixels' color and transparency information, as this always coincides with the imaginary rectangular/ square pixel grid and pixels only get re-arranged. Only rotations at different angles will enforce resampling, meaning that in particular edges will be recalculated to keep them visually smooth. Doing this multiple times will result in softening, as the way Photoshop works, it has no knowledge of previous transforms and will apply the full sampling again in a "dumb" manner. Smart objects avoid that limitation, as they concatenate operations, i.e. a rotation of +60 degrees followed by one -20 degrees will be treated as a single 40 degree rotation. Likewise, CS4's canvas rotation, is merely a secondary rotation applied to the screen buffer, not affecting the image itself.
Mylenium