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09/11/2004 08:12:43 PM · #1 |
An excerpt from this article, which describes a sharpening technique based on resizing the image:
For example if one resizes by successive 109% steps it takes just a hair over 8 steps to achive a final 200% size increase. It will then be found that the resultant image is often noticeably clearer than that which can be achived by normal image sharpening filters. Hence this particular method of stair-step resizing has come into a fair amount of use recently.
Is this a widely used technique? If you've used it in the past, what are your thoughts on this method?
I did a quick test run on a photo and it seemed to do a fairly nice job... |
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09/11/2004 08:13:30 PM · #2 |
I frequently resize prints in 5% increments.
-Terry
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09/11/2004 08:17:45 PM · #3 |
Originally posted by ClubJuggle:
I frequently resize prints in 5% increments.
-Terry |
Instead of USM or as a complement to it? |
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09/11/2004 08:26:33 PM · #4 |
Originally posted by thatcloudthere:
Originally posted by ClubJuggle:
I frequently resize prints in 5% increments.
-Terry |
Instead of USM or as a complement to it? |
This is not really a substitute for sharpening, but a better technique for upsizing. The algoriths used seem to to a better job interpolating the added pixels when this method is used. I generally find in any case that little sharpening is needed when upsizing.
-Terry
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09/11/2004 08:34:00 PM · #5 |
From reading the article, however, I understand it to be a method for sharpening. Once the image has been upsized by 9% 8 times, it can be reduced about 50% back to it's original size.
I tried this and I did end up with sharper edges.
So...has anybody used this method for sharpening? |
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09/11/2004 08:39:30 PM · #6 |
I haven't tried this yet, but the Photoshop CS manual recommends enlarging photos in 10% increments until you get the size you want. It recommends this technique for enlarging photos (though the author admits not knowing why 10% increments seems to enlarge photos smoothly), but doesn't say anything about using it for sharpening.
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09/11/2004 10:18:08 PM · #7 |
Some dude on some forum (hey, google if you really want results better than my memory) recommended this for getting good, sharp results:
1. sharpen in native size (i.e., the image before resizing)
2. upsize 20% beyond desired final size
3. sharpen again to "recapture" lost detail
4. downsize to final size (bicubic)
I've never tried this myself. Sharpening is tricky business, probably nearly as tricky as color management. For output (print) sharpening, it's recommended that you apply sharpening such that halos are 1/50th to 1/100th of an inch in size (e.g. between 3 and 6 pixels at 300dpi). The result won't be pleasing (when viewed on the monitor) so if it proves difficult to do it, then do your sharpening at about 50% zoom until visually acceptable.
It's alchemy I tell ya! |
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09/12/2004 12:13:21 AM · #8 |
Using an enlargement followed by a reduction in size back to the original doesn't seem to offer much in the way of control. Sure a person could vary the percent increase going up, vary how high to take it and then vary the percent coming down -- that there does not seem to be any indication of what would work well until all is done. This lack of control leaves it as a trick, or general guideline, that once a general formula is found to work, continue using it on all images instead of looking at sharpening on a per image basis.
David
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09/12/2004 01:58:00 AM · #9 |
How about a before and after view at about 200%?
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