Understanding Histogram
Mark Wallace
Lesson Info
24. Understanding Histogram
Lessons
How To Open Files
01:10 2Using The Home Screen
01:49 3Exploring The Interface
02:36 4Understanding Workspaces
03:04 5Tools and The Options Bar
01:56 6Finding Hidden Tools
02:31 7How to See What You’re Working On
06:19 8Selecting Things
07:06More Selection Tools
10:34 10Testing the Magic Wand and Quick Selection Tools
03:55 11The History Palette – Undoing Things
02:47 12Menu and Item Shortcut Keys
02:28 13Non-Destructive Editing
02:14 14Working with Layers
09:11 15Groovy 3 Exercise
10:38 16Layer Effects and Styles
04:25 17Layer Masks – Karen on Beans
06:41 18Using Adjustment Layers
04:36 19Using Filters
03:06 20Advanced Compositing Using Layers
07:42 21Non-Destructive Editing Techniques
03:17 22Understanding Smart Objects
05:16 23Smart Sharpen
04:36 24Understanding Histogram
04:08 25Adjusting Curves
03:46 26The Healing Brush Tools
07:28 27The Clone Stamp Tool
05:24 28The Burn and Dodge Tools
03:41 29Neural Filters
07:52Lesson Info
Understanding Histogram
So let's go back over here to Photoshop and remember this once again. So here is our histogram. I'm gonna zoom out really fast. And what we're looking at here is, this histogram is showing us the distribution of luminosity values of luminosity values from the darkest to the brightest in our image. So if we look at this, and again, I'm gonna zoom in on this just a little bit, and you can see over here on the left, this is showing us absolute black, how many pixels are absolute black. And then as we go to the right, we're seeing how many pixels are dark gray and a little bit lighter gray, all the way to the middle of the image, which is middle gray, sort of just gray. And then all the way over here on the right hand side would be absolute white. It's gonna show us the distribution of values. And one of the things that can be confusing is if you look at an image like this, the left side is dark and the right side is light. And that corresponds to what this looks like. But remember, it's l...
ike the kids in the classroom. It doesn't matter where the pixels are in the image, it's just showing a distribution of those pixel values. So we have a lot of dark values, a lot of gray and no white at all. and no white at all. Now, to adjust our image, we can use the histogram to help us understand the exposure. So let me show you how to do that. So I'm gonna close this histogram window and we're gonna go over here to our layers palette. And then I'm going to make a new adjustment layer called levels. called levels. And right off the bat, in the levels panel you see the histogram. So this histogram is showing us again how many black pixels we have, how many gray pixels that we have, and how many white pixels that we have. Well, we don't have any white pixels in this image. But what I can do is I can take this slider right here and I can say, you know what, I'm gonna bring this over and now what I want this to do is I want this to be the white area, is I want this to be the white area, this to be the gray area and this to be the black area. When we look at our image, I'll close this. You can see, we have a white, we have a middle gray, and we have absolute black. That's what the levels help us do. We can change where the grays are. We can say these mid-tone values, these gray values, I want them to be a little bit brighter. Oh, wow. Look, there's color in this image. Who knew? Or I wanna make them a little bit darker. You can change where those mid-tones are. You can change where the blacks are. You can do all of those things using these levels. Now there's many tools for adjusting the exposure and luminosity of different values. And almost all of them use a histogram to help us understand where the values are in our image. Let me show you something else. I'm gonna reset these levels here. So we go back, all the way back to the normal. In fact, I'm gonna click this, this is going to reset everything. So we're back to where we started. And I wanna just show you something, just so you understand that the distribution of values is not correspondent to where the images are or the pixels are in the image. So, if we have our histogram here, it shows dark on the left. There's dark on the left. We have bright on the right. There's bright on the right. But watch this. If I go to this layer and I say, image adjustments and then what I'm going to do here is actually, I'm gonna say image rotation. Flip canvas horizontally. Flip canvas horizontally. When I do that, that flips this image around. And notice, nothing changes. So we still have the brights over here on the left, the darks over here on the right. The histogram is exactly the same. It doesn't matter what I do to this image. I can rotate it like this, bunk, I can rotate it like this, bunk, and it's gonna show the same thing. And so, now, we have this bright line right here because we have a white background, we have this transparent background. But the rest of it is the same.
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Adobe Photoshop