I've been monkeying with Lightroom and post-processing a while but without any real guide or plan to follow - which means some areas I don't know about, don't understand, or just haven't used. One of those is the Tone Curve panel and it's various options. I can just play with the sliders of course but I'm not sure I fully understand the mechanics of what it's doing under the hood and why/when you would want to apply certain types of adjustments. Anyone know of any good reference articles/videos or books that address this topic? I googled up some but figured I'd ask here too. Ideally I'd like to understand *what* I'm actually doing and why it matters, rather than just tips on good settings.