"<strong style=""color: gray"">Using the Curves Dialog to measure points in your image</strong> This feature is the great secret of being able to use curves well.  With the curves dialog open, click the mouse on any spot of your image and a point will appear on the dialog showing the value of the color at the spot on the curve.  Drag the mouse cursor (move it with the mouse button (right mouse if you have more than one mouse button) held down, and the point will move along the curve to show the value dynamically. I am about to make very good use of this feature in order to implement the next step of the recipe. <br><br> <strong style=""color: gray"">4. Establish light and dark points</strong> Generally, images look best when they use the full range of available contrast.  That means that they have a darkest spot which is truly black and a lightest spot which is truly white. It's actually quite a bit more complicated than that, but it's easiest to understand by doing than by theorizing.  I used the <i>Channel</i> drop down to switch to the <i>Lightness</i> channel of the curves dialog.  Then I used the mouse to look around for the lightest point I could find in the image.  It's in the clouds.  You can see that it's about 5% above the 0,0 point of the graph, meaning that it isn't as light as it could be."
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