What Does Retouching Involve?
I put off learning about retouching stacked photos for as long as I
could. I did not like the idea at all and I didn’t really try to even learn
what it involved. And it is difficult, relatively. For those of you who
may be like me, let me tell you what retouching is actually like.
A typical stack may be something like ten to twenty or more photos,
each a separate focus layer. These are the layers that are merged
together but there are gaps between where the layers overlap and
these can cause artifacts – unwanted glitches in the photo. There
are other factors I won’t go into here.
In retouching software we can select any single layer without the
artifact and use it to overwrite the area on the composite photo with
the artifact. It reminds me of using “PressType” years ago to
overlay type on paper. Many if not most artifacts can be repaired,
smoothed, or removed, but not all. Some photos cannot be
salvaged, usually when there are objects that are two far in the
foreground – too much distance between parts of the subject. And
of course if the wind blows (and it does around here) any
movement can make an error difficult to impossible to repair. Often
you can just delete that layer, restack, and be OK.
The process seems smooth enough until you encounter any object
that is round or that extends from the back of the photo toward the
front. In other words as long as the subject is approximately two-
dimensional (flat), it is not so difficult. However, as soon as
something extends
toward the lens we no longer have a flat subject which means each
layer has some (and only) part of whatever-it-is that needs
retouching and this situation is much harder to cope with.
And then there are places where the increment between layers is
too wide; there is no overlap. This is really a case of “operator
error” where we needed to use shorter increments. In this case
there is little to nothing that you can do to remedy the situation,
although in some cases you can blur out the whole background by
using a background layer. It gets complicated.
It becomes a case of how much time do you want to devote to this
photo and sometimes I ask myself why don’t I just take a standard
one-focus-spot photo and ignore all of this focus-stacking stuff. This