Additions:
Below the histogram is a Output Black slide, as well as an Output White slider. These control how black the blacks are, as well as how white the whites are. Pulling these sliders around will decrease the contrast. Try experimenting with them to get the hang of it.
Why do I need to use this complicated histogram thing when I can just use the contrast slider under the "Adjust Colors..." menu option?
Great question. What the contrast slider does is uniformly move the black and white sliders in. For an image that would produce the histogram above, we don't want the white point to move in as much as we want the black to move in. The adjust contrast slider would make everything either too white, or not black enough. The levels controls allow us to modify things more precisely, and get a cool looking bar graph too!
You might also try using "Auto Levels..." featured under the Levels command in the Image menu. It will give a good attempt at moving in the sliders to the right spots. This can be a great option if you're in a hurry.
Deletions:
Below the histogram there is a Output Black slide, as well as an Output White slider. These control what how black the blacks are, as well as how white the whites are. Pulling these sliders around will decrease the contrast. Try experimenting with them to get the hang of it.
Why do I need to use this complicated histogram thing when I can just use the contrast slider under the "Adjust Colors..." menu option?
Great question. What the contrast slider does is uniformly move the black and white sliders in. For an image that would produce the histogram above, we don't want the white point to move in as much as we want the black to move in. The adjust contrast slider would make everything either too white, or not black enough. The levels controls allow us to modify things more precisely, and get a weird looking picture to look at too!
Edited on 2008-01-27 16:23:46 by BradEllis
Additions:
Levels
Levels are a different way of looking at your image. Instead of the picture being displayed in its normal viewable state, its shown as a bar graph called a histogram. The histogram is essentially a count of how many times each color shows up in your image. In the image above we have a nice white color that is showing up a lot in our image, as you can see by the spike in the graph at the right end. On the other hand there aren't many deep blacks in the image, as you can see by the low point on the left. This is often perceived as low contrast, so why don't we bump that up a little.To correct or modify levels, simply drag the two triangular slider controls on the left and right sides at the bottom of the histogram. Doing so will instantly change the image on your canvas, hopefully for the better. To improve this image, we should pull the black slider on the left over to the right until it gets to the bottom of that little mountain, and maybe we should pull the white slider in a smidgen too. Every image is different, so look at your changes and make sure they are to your liking before you hit 'OK.'
Below the histogram there is a Output Black slide, as well as an Output White slider. These control what how black the blacks are, as well as how white the whites are. Pulling these sliders around will decrease the contrast. Try experimenting with them to get the hang of it.
Why do I need to use this complicated histogram thing when I can just use the contrast slider under the "Adjust Colors..." menu option?
Great question. What the contrast slider does is uniformly move the black and white sliders in. For an image that would produce the histogram above, we don't want the white point to move in as much as we want the black to move in. The adjust contrast slider would make everything either too white, or not black enough. The levels controls allow us to modify things more precisely, and get a weird looking picture to look at too!
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Oldest known version of this page was edited on 2008-01-27 15:27:05 by GusMueller []
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