I advocated dialing back the image magnification in a recent "Tip of the Week." When you intend to print your image on a desktop inkjet printer, View | Actual Pixels and 100% are poor choices.

The native resolution for different DSLRs varies. A Canon D30 image has 3 million pixels, while a Canon 10D MkII image has 16.7 million pixels. Viewed at 100% zoom, a Canon 1Ds MkII image is literally the size of a poster.

You simply cannot judge how the image will look when it is sharpened and printed at a more reasonable 8x12 or even 12x18 size from a 100% zoom.

I gave some quick rules of thumb for zooming in. I recommended 40-50% for 6 megapixel cameras, smaller for 8 megapixel cameras, etc.

My preference is to use View | Print Size. Instead of a 100% view, with a Canon 1Ds MkII, you instead get a zoom that is between 20 and 25%.

When I sharpen, I adjust the preview window in the Unsharp Mask (USM) filter to 800%. This is the maximum zoom the little preview window can manage. I can count the pixels in the sharpening halo and also watch the halo as I make my USM adjustments.

You can do the same with the Highpass filter sharpening, if you apply the Overlay or Soft Light blend to the duplicate layer before you open the Highpass filter dialog.

You might have noticed that I did not increase the Highpass preview to 800%. I find it most helpful to view the Highpass preview at 100%. (I never said 100% zoom has no utility at all in sharpening.)

As I mentioned before . . . It is helpful to use View | Print Size when sharpening and to set the USM preview to 800% to get control over your sharpening. None of that is a substitute for a test print however. Monitors emit light. Prints reflect light. Soft proofing will get you a long way towards an excellent print, but you still need to hard proof.

Cheers!