Adobe Photoshop CS5 Tutorials
Color Correcting Photos / Understanding Histograms
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Subtitles of the Movie (Adobe Photoshop CS5 / Color Correcting Photos / Understanding Histograms)
I want to take a moment and show you something here inside Photoshop called Histograms and as previously mentioned, this is going to set us up for some more advanced color correction and also for some non-destructive color correction as well. Now, of course we need a sample file here so I'm going to of course double click on my gray background and we should have a file inside our Project Files Folder called Road.jpg. Go ahead and look for that guy, pop him open. As you can see, this guy is really washed out but what's really cool is in the coming lessons, in the coming exercises you'll see how amazing we can make this image. We're going to pull a lot of the color back into this guy. But before we get to all of that, what I want to see is some kind of a visual representation of the color inside my image and that's exactly what the Histogram is going to do for me and the Histogram is found inside the Histogram Palette inside Photoshop. So I'm going to head up to my Window Menu and then down to Histogram. Now, not History. We want Histogram. You know what I'll do here is I'll just tear him away so we can actually see this guy a little bit better. Let me just get rid of those other guys. Alright, so exactly what the Histogram is is a graphical representation of the light distribution inside my photo or inside my image. This graph that I see here is called a Luminance Graph and what we have on the left-hand side is all of the shadows. In the middle we have our midtones and on the right-hand side we have all of our highlights. So obviously inside my image here you can see a lot of the pixels are concentrated in the center and towards the highlights. There really isn't a whole lot happening in terms of my darks because everything's very washed out inside this photo. Now, what might be a neat exercise for you to do on your own is to compare this image with perhaps another photo. Maybe one of your photos and compare the histogram back and forth between the two images and see the different changes that you get. OK, now let me explain exactly how this histogram is mapping things out. What I'm going to do first of all though is I'm going to head to the Histogram Palette Menu and I'm going to choose Expanded View. Right now we're in the Compact View. Expanded View makes things a little bit bigger and a little bit easier to see. Now, running across the bottom of the graph we have a scale that goes from zero to 255. So we have 256 levels of brightness inside each channel or 256 luminance levels. That's the idea here. So zero being again on the left-hand side and 255 being on the right-hand side. And then the vertical axis, if you will, in this graph, the height of each of these lines represents the number of pixels at that brightness level. So for example, here I can see there's a lot of reds in the sort of spiking here in the midtones and the blues spike there as well, as do the greens. So in other words, I actually have three graphs overlapped on top of one another because I'm inside an RGB image. See how everything kind of comes togetherright? Probably way back when we were talking about RGB and CMYK and black point and white point you might have been sitting there going why am I watching this? Why does this, how does this actually pertain to me making my photos look good? Well, here's the point where everything starts to come together here. So we can do a couple of different things here at this point before we actually go and do something about our photo. In terms of actually looking at our histogram here, from the Channel Drop-Down Menu of course I'm looking at my colors but what I can do is I can isolate my individual channels. I can say show me just red or show me just green or of course show me just blue, right? Or I could say give me the composite, the RGB. Now, this is normally what I look at myself, the composite view but a lot of people like the colors. They like to see all the colors in there .It's entirely up to you. You know, the other thing that you can do and I'll show you this real quick, is you can head back to the Histogram Palette Menu and choose All Channels View. Go ahead and choose that guy and all of a sudden your Histogram Palette is huge. There's our composite on top, I guess you could say. All of our colors, the red green and blue and then below that there's my red, there's my green and of course at the bottom, there's my blue. Now, of course, it's entirely up to you if you want to use your Histogram Palette in this way. Normally myself, I don't go too crazy with histograms. I don't go too crazy with color correction. So myself, I leave it on either Expanded or the Compact View, usually even just the Compact View is fine for me and you know, the other thing too is of course I can go back to just my RGB, something like this, right? And then of course I can go back to my Compact View like that. So this is normally how my Histogram Palette looks myself but again, you can go nuts here. So I hope that makes sense in terms of the Histogram Palette, what it is, how it works. Histograms confused me for the longest time until I realized in my head it's a, it's basically a bar graph and I've got an axis across the bottom which measures light distribution and I've got a vertical axis which measures the amount of light at that point inside my image. I hope that makes sense for you.
Tutorial Information
| Course: | Adobe Photoshop CS5 |
| Author: | Geoff Blake |
| SKU: | 34150 |
| ISBN: | 1-936334-46-1 |
| Release Date: | 2010-08-06 |
| Duration: | 7.5 hrs / 95 lessons |
| Work Files: |
Yes |
| Captions: | No |
| Compatibility: |
Vista/XP/2000, OS X, Linux QuickTime 7, Flash 8 |
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