Nich,
Proficiency with curves adjustments allows one to remap the tonalities of an image.
Now what does that mean? Well we get clues as to the structure, dimensionality, textures and mood of a scene by how light plays off the surfaces and reflects towards us so we can build in our brains a "picture" of what is outside our bodies. The picture that we see is not what is there! It's just a construct whereby we as organisms imagine and can "work out" our relationships with our world. It so happens there is usually enough light round and that we are good at picking up visual clues. When we use a piece of light-sensitive film or else a digital silicon chip, light falls on a cold dumb heartless material. It knows nothing about how the brain likes to process light and dark and changes in perspective and other nuances that allows us to translate what light we receive to 3 dimensional images of what's before us. The image sensor or film have neither memory nor interest in the source of the light bathing them. Our brains do the pattern recognitions without us thinking and even when poorly lit, we can add the missing information.
Also, our brains have the extra advantage of overlaying information from two positions, one for each eye, so there is a highly developed facility for depth perception and
separation of surfaces. As we move our heads, we can order everything to a series of distances from us. Our perception, all from what otherwise for a machine would require instant geometrical calculations is that
nearer objects will seem to shift their positions
away from our own direction of movement with respect to
and more than progressively distant objects. So we are asking of a
single, stationary flat piece of plastic or silicon, the delivery of a likeness of what we see with our
two eyes and brain! The way we can succeed in this is to
maximize tonal differences and character so as to enrich our pictures with easily interpreted visual clues.
We could say, "open the shadows", "tame the highlights", increase the slope of the change in contrast" and so forth, but the best way to approach this is by examples and there are already a number of good tutorials for you to look at. Two are given below.
Learning "curves" is a fundamental step in having some creative control in how your images will appear. (Once you get the basics, Lightroom has a great paradigm in that it limits what you can do to mostly sensible changes. So that is worth looking at.)
I'd get a taste first at Luminous Landscape with the tutorial by
Miles Hecker . It's simple and a good start.
Then you can go to Cambridge color:
here as their illlustrations, as you can see, below, are very clear. As they approach the subject differently you will end up with a pretty good understanding. In particular their "roll-over" illustrations are very easy to follow and well done.
Credit- Cambridge Color
Then practice. I hope this helps!
Asher
