IMO one *must* perform capture sharpening before stitching. Capture sharpening should occur on the original pixels, in their original placements. Stitching includes warping (like "free transform"), which means that pixels vanish, other will be interpolated, neighbours "go apart", etc. No talk can be about "capture sharpening" after the stitching.
Panopeeper? You want to do capture before all the warping and messing of the pixels? First time I've heard it suggested that you would want to sharpen prior to distortion rather than capture sharpen when you have the final finished product. If you sharpen prior to stitching then all your sharpening will be messed up completely by the distortion and the finished stitch will have some sharp, some smearing, some weird stuff and a million artifacts.
I do quite a bit of stitching to make mural size gallery laser prints. Here are my thoughts on this (and I'm here to mull this stuff over and learn so I don't necessarily think I'm always right):
When software stitches, it does warp and localized interpolation (more so on images not shot well). This averaging or softening occurs
irregardless of capture sharpening at the raw stage or not. So, some localized areas can be slightly softer regardless of what pre sharpening method is used. If these areas are detectable and are not desirable then a touch of additional custom sharpening (in those specific areas) before printing should suffice to give the perfect illusion of consistent sharp detail.
I (both for stitches, or non stitched images) do the capture sharpening at the raw stage in ACR 5.3 because of what I see as the overall superior benefits of raw capture sharpening. This is the very reason I went back to the drawing board on the aforementioned pano image. I see (maybe I'm crazy) a big benefit in
discernible detail in mural sized prints when the images are capture sharpened in ACR at the
raw stage.
The comment:
If you sharpen prior to stitching then all your sharpening will be messed up completely by the distortion and the finished stitch will have some sharp, some smearing, some weird stuff and a million artifacts.
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may be true, but I have yet to see this in my stitched maximally enlarged prints.
As a counter theoretical argument, maybe it is possible that the stitching software (like PS CS4 Photomerge) will do a better and more accurate stitching job when the pixels it is trying to locate, compare, overlap and work with are more
defined? I don't know.
Either way, I have yet to see
any problems related to raw ACR capture sharpening on stiches or otherwise, in a finished print.