/HʋʢɚKʝɦWɛ
Make good photos
look even better
Mike Bedford provides guidance on how to
use the GIMP photo-editing package to
makedramatic improvementstoyourphotoshoto editing is commonly thought of as a means of
correcting common errors such as under or over-
exposure, or lack of sharpness in a photograph. Right
attheoutset, therefore, we need to put the record straight by
statingour view on the main purpose of photo editing to the
photographer. Although we’ll give some brief guidance on
error-correction techniques, this is by no means our main
emphasis. Instead we’re going to be investigating how photo
editing can make a good photo even better.
If you’ve never really bothered with photo editing, you
might be of the view that enhancing an image in this way is
going to result in only a slight improvement and is barely
worth the effort. This couldn’t be further from the truth.
Many professional and serious amateur photographers have
suggested that post-processing is every bit as important as
taking the original photograph, and we wouldn’t disagree.
And if you’re unconvinced, try it out yourself – you might
be surprised.
The software we’re featuring is GIMP (GNU Image
Manipulation Program), specifically version 2.10.14. Although
it’s not quite in the same league as Adobe Photoshop, GIMP is
a reasonably well-featured photo editor, and unlike the Adobe
offering, it’s free. If you have a different package, it might be
able to do most of what we describe here, but we make no
guarantees, and entry-level packages will almost certainly
have some serious drop-offs.
Before getting down to business, we need to remind you
to only ever edit copies of your photos. This way, as your
photo-editing skills improve, as they almost certainly will, if
you subsequently decide you could do better, you can try
again from square one. And as a final preliminary remark,
remember that this is not an exact science but an artistic
endeavour. This means that there are no right and wrong
ways of doing things, and while we hope and expect that
most people will recognise the end result of your efforts as
a substantial improvement, someone else could easily
choose a different way of enhancing a particular photo.
Just experiment.Setting levels
We’re going to be looking at several processes, and in most
cases they can be carried out in any order. However, you really
ought to look at levels first, partly because it will reveal
whether or not you’re likely to get a really good result, or
whether the best you can hope for is damage limitation.
Select Colors > Levels to display the Levels dialogue box.
You’ll notice that it shows a graph of the brightness levels in
the photo, and this will often be a bell-shaped curve, although
it might have an additional peak or so, as in our screenshot.
Occasionally, however, you’ll find that the curve doesn’t drop
to zero at either the bottom or top end – or in other words,
that the bell curve appears truncated at one end. Thisindicatesthatthephotoiseitherunderexposedor
overexposed, and this is bad news because it suggests that
there were brighter or darker elements in the scene that have
not been recorded. You could make the overall impression
better (see the correcting photographic faults boxout), but it
will never be a really good photo because detail in either the
highlights or dark areas is missing. In this case, you might
decide it’s pointless going any further.
If the levels curve isn’t truncated, though, it will often be
the case that there’s scope for significant improvement. In
many photos, the bell curve doesn’t occupy the whole of the
area from the left to the right. Unlike with a truncated curve,
this doesn’t mean that information has been lost, but it does
indicate that your photo doesn’t include the whitest of
whites or the blackest of blacks. Sometimes this might be
the desired effect – for example in a misty twilight scene
– but more commonly it means that your photo could be more
dramatic. To correct this, move one or both of the triangular
sliders below the graph until they line up with the left and
right edges of the curve. You’ll see the effect in real time as
you move the sliders. And if you subsequently open the Levels
dialogue again, you’ll notice that moving the sliders have
effectively stretched the curve to occupy the complete area
from left to right. Even this very first step in enhancing a
photo can make a huge difference.Adjusting curves
Next up, we’re going to investigate what GIMP refers to as a
curve (not to be confused with the levels graph that we’ve just
looked at), so choose Colors > Curves to display the CurvesP
The levels graph lets you judge whether your photo is properly exposed, and, if
so, allows you to make sure it contains all levels of brightness from black to white.44 |^ |^ March 2020