What Is A Histogram? (Part 3): Using Curves
Hey guys here's the third video in the series about histograms -- if you need an overview about what the heck a histogram even is, go back to the first video and start there, then meet me back here in a little bit.
Today we're talking about color curves. Color curves are awesome because basically it's a histogram but you can mess with it and change it. Over on the left side here, this is all darks, and over on the right side here, this is all brights.
And I've got a line here, it's almost like a string that I can pull whichever way I want, to basically change how things are either dark or bright.
Now you can really really mess up your image quite quickly with curves, but you can also make some awesome changes if you know what you're doing. First things first, look at this point right here. This point is saying, left to right, the LOCATION for what you're changing is the DARKS. I'm over here in the dark area all the way over to the left. So that location is what you're thinking about.
As you go UP AND DOWN, that's going to be WHAT YOU CHANGE IT TO. So right now, the darks are plotted on this graph -- if they're dark (on the left side) then this line is saying, okay leave them dark. Now what we're going to do next, is if they're dark (on the left side), but now I'm going UP, it's saying TAKE THE DARKS that are in this area, and pull them up towards white/bright.
And if I do that, then the entire image is white. If you see the line, it's pulling all this other stuff up as well. I'm basically taking the shadows (and everything else with it, because it's an unbroken line), and I say... "okay you guys are going up towards white, because I don't want you down towards shadows any more."
Let's go to the middle, let's go to the mids. We're going to pull the mids over and down. Take a look at this line! Look at what's happening to this line. Look at the shadows here. The shadows STAY as shadows. The higher shadows are actually pulled DOWN to be DARKER. The MIDS are pulled DOWN to be DARKER. The upper MIDS are pulled DOWN to be DARKER, and we only end up near the highs almost exactly where they connect up top. So I pulled down almost everything else except the highest of the highs (brightest of the brights), just by grabbing that little dot in the center and pulling it down this way.
Now let's go the opposite way -- let's go here -- what have I done?
Remember the shadows are staying as the shadows, but as I go higher (not perfectly dark but a little bit brighter), that's going to be remapped up here -- it's going to be pushed up higher. So this line basically, this line in the center is a line of perfect, unchanged, nothing being different. If this line is straight, that means NOTHING is different. Because this mapping of dark to light going left to right, correlates perfectly with the dark to light over here on the Y-AXIS.
So if you're going to push ABOVE that line, you're going to make things brighter and if you push below that line, you're going to make things darker.
Let's do two separate things now -- let's take the upper-mids higher and let's take the lower-mids lower. What did I just do here?? I just made it MORE CONTRASTY.
This is how you create contrast. You're pushing the highs higher and you're pushing the lows lower. If you overdo it, everything below the middle will be trashed dark. It's taking these mids here and it's pushing those all the way down. It's pushing the shadows down, higher shadows down, lower mids down, mids down, then when I PASS THAT MIDDLE POINT, those upper mids get shoved all the way up to the top, those upper mids get shoved to bright, the lower highs get shoved to bright and the highs are already at bright.
So you can see there's this complete white, and then just a bunch of dark.
Try to FORGET ABOUT COLOR as we do this -- don't think about orange, red, pink, whatever. Try not to think about color -- we're just mapping how bright certain things are. PLAY WITH THIS CURVE.
That's almost the best way to learn a histogram is basically to be playing with it (by using curves) because you're able to...
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