I'd like to point out that the photos straight out of the camera
are technically as "sharp" as they will ever get. Adding sharpness
(or USM) in PS creates an effect whereby the exisiting sharpness is
"highlighted" by image manipulation. Kind of like drawing a black
line around a border emphasizes what is inside the border.
Our eyes have been trained by snapshots to demand a high degree of
edge clarification in photographs. This leads our brain to believe
the image is more focused and sharper. In reality, the image was at
it's best before adding sharpness to it! And interesting enough,
the same methodology is not always true for other fine art- like
oil paintings. But it can be there too. Artists frequently add
emphasis and color around objects to create better focus shall we
say. But the focus was already there to begin with. But we
sometimes need to emphasise that.
In reality, we unsharp the edges (take away existing natural
sharpness) around predominant areas and create a second or third
dot or line that draws attention to those edges. And because this
is a modification of the actual image, we must be careful to do
this without creating artifiacts or drawing unneeded attention to
this "tweaking". Done properly, this can yield great results.
This is why I'm not a big fan of including USM (unsharp mask) in
your batch work. As Ger Bee has already mentioned, this is the last
thing to be done. Sort of like the artist putting the final touches
on a painting. USM is something to be done where it is needed- and
avoided where it is not needed. But that's not all.
In the digital workflow, background and foreground objects respond
completely differently to USM. Have you ever tried to USM a child
in the foreground but found that the background is what is being
affected? Often you need to USM just a certain part of your photo--
maybe just your foreground object- and leave the background
relatively untouched. Because this is done on an image by image
basis dynamically, it is best not to include this as a batch
function. PS gives you the tools and spatial controls to do this
effectively-- but you really need to practice with it.
Add to that the fact that USM is usually going to be different for
print than for web which even adds more work to the flow. Always
keep your original TIF or NEF handy so you can repurpose your
images for different media.
I'm always learning more about USM from reading the posts in these
forums, and especially by trial and error on my own. By examing the
work of others, you can learn more about these techniques and
improve your own work.
