Join Deke McClelland for an in-depth discussion in this video Winning Curves tips and tricks, part of Photoshop CS6 One-on-One: Advanced.
In this movie, I'll share with you a few tricks that should make your life easier when working with curves. You will notice that I've gone ahead and renamed my layer contrast. I'll double-click on it to bring up curves inside the Properties panel, and just to make sure that I'm protected, because I am going to make a bunch of modifications here. I am going to go up to the flyout menu and choose Save Curves Preset and I will go ahead and name this file Black & white heft for example. Make sure to save your preset to the default Curves folder which is the subfolder someplace in your hard drive and then click the Save button, and you'll see Black & white heft in my case listed among your Presets, which means you can come back to this graph anytime you like.
Now it's showing you how you can press the Control key or the Command key on the Mac and click on a point in order to delete it. I'll go ahead and press Ctrl+Z or Cmd+Z on the Mac to undo that change. What happens when you Alt+Click or Opt+Click or Shift+Click? Well, if you Alt+Click inside the graph you are going to increase the number of gridlines, that would be an Opt+Click on the Mac. If you Alt+Click or Opt+Click again, you will reduce the number of gridlines. And all that is, is a preference. This is not a snapping grid. So it won't help you nail the location of points. If you Shift+Click on points, you will select multiple points at the time.
So I'm going to click and then Shift+Click on these three points right there. For example, I will drag them upward and typically this is what you want to do. If I were brightening the darkest colors for example, I would drag these points upward or I could darken them by dragging downward. You typically don't want to drag back and forth, because in my case if drag to the left, I end up losing some of those points and I have to drag back to the right again in order to regain them. What you most typically do hear--I'll go ahead and press Ctrl+Z or Cmd+Z on the Mac to reset those points--is just select a handful of points and then nudge them from the keyboard.
So if I wanted to brighten my shadows and midtones I would press the Up Arrow key a few times in a row and notice that the Output value now reads 8. That is not an absolute luminance level as in almost black. That is a relative luminance level meaning that we have brightened all three of these points by eight. All right. So far I've showed you how to set and modify points on a curve, but you can also draw a custom curve graph using this Pencil right here. So for example I could go ahead and just draw a curve across the graph and presumably you're going to start somewhere down left and move your way up right, because if you go in the opposite direction, for example from up left to down right, you'll end up inverting the image like so.
You can also draw crazy graphs if you want to. I will go ahead and turn off these two grayscale layers right there so that we can see curves applied to the full-color image, and now notice if I draw something along these lines, I'm creating what's known as an arbitrary map, which among other things can end up generating psychedelic effects like these here, and you're probably not going to take advantage of this very often, but you may sometimes find these sorts of arbitrary maps to be useful when working with masks.
Now if your curve ends up having a bunch of gaps in it as mine does or it ends up spiking in certain locations, you can soften the transitions by clicking on the Smooth button. So notice each time I click Smooth, I end up smoothing out my graph like so and then I could decide this wants to go back up and then I could click Smooth a few more times. Now a more practical way to take advantage of the Pencil combined with Smooth is to Shift+Click inside the graph. Let me show you what that looks like. I'll go and turn those two grayscale layers back on and then I'll click in the bottom left corner and Shift+Click at this location here and Shift+Click again, and notice each time I Shift+Click I end up connecting my click points with straight segments.
So that's a quick way to roughen a graph, that ends up giving us this posterization as you can see here inside the image window, however. So get rid of the posterization and smooth out the transitions you click on the Smooth button, probably three or four or even five times in a row. Now the great thing about working this way is you don't have to mess with the values and Photoshop will actually create the values for you if you just go ahead and click on this little Points button there, notice Photoshop adds points to the graph, automatically sets the Input and Output values, and you're done. All right.
Another thing to note, if I grab the Target Adjustment tool, I was showing you how if you move your cursor in the image, and my cursor is in the woman's forehead right here, you can see the bouncing ball, in my case in the upper right portion of the graph and if you click, you end up setting a point to that location. Well, you also have three other graphs to work with when you're working inside of an RGB image. You can independently modify the Red, Green, and Blue channels. So there might be times where you want to set, instead of a composite point as we created just a moment ago, a channel by channel point.
So in my case, let's say I move down her brow here so I can get a kind of darker color, and right about there I will press the Ctrl+Shift keys or Cmd+Shift on the Mac and I'll click. And that goes ahead and sets a point inside of each one of the independent channels. So notice if I switch to the Red channel, I've got a point right there, and so I can press the Up Arrow key to add a little bit of redness to my otherwise grayscale image and now I'll switch to the Blue channel and press the Escape key so that the menu is no longer active and press the Down Arrow key in order to achieve a kind of Sepia effect there, and then I might switch over to the Green channel and press Escape once again and then press the Up Arrow key, maybe just a couple of times so that I don't end up making the image look too yellow and I achieve this effect here. All right.
Now I am going to switch back to the Composite version of the image like so, and you can see those channel by channel curves represented in Red, Green, and Blue inside the composite graph. All right. Let's end things with a look at what happens when you're working inside of a grayscale image. So for the moment I am going to go ahead and click on this Curves layer here inside the Layers panel, and press the Backspace key or the Delete key on the Mac to get rid of it, and then I'll go up to the Image menu, choose mode, and choose Grayscale and I will a get series of alert messages asking me if I want to rasterize my Smart Object.
I do, so I'll click the Rasterize button. Do I want to get rid of my adjustment layers or merge them? I want to merge them, because otherwise I'll lose those adjustments. And then finally, do I want to discard the color information? I do, so I will click Discard and I am left with a single layer as well as the single channel gray here inside the Channels panel. Now if I dropdown to the Black/White icon and I choose the Curves command, you can see here in the Properties panel that everything is backward. We have the white triangle on the left-hand side and the black triangle on the right side.
And the reason for this is these guys no longer represent Luminance levels, instead they represent ink values. So if I were to click on this lower left point, you can see that the value is 0. By that it means 0% ink which is paper white and if I press the Plus (+) key in order to advance to the upper right point, its value is 100 meaning a 100% ink, so black. What that does is it ends up just messing with the way your brain works inside Photoshop in my opinion.
I can go ahead and reload that preset I created a moment ago by choosing Black & white heft, but now the whole thing is upside down and backwards. So I'm raising the points in order to darken those shadows in the upper right region of the graph and everything that's occurring with the highlights is in the down left region of the graph. If you don't like to work that way then I have to admit I don't, because everything else in Photoshop is based on luminance. Then you can click on the flyout menu icon and choose Curves Display Options and then switch Show Amount of from Pigment/Ink% to Light (0-255) and that restores the graph to its more familiar behavior.
Then click OK, and by the way, this will change the graph for all future grayscale images as well. If you work in CMYK and you prefer to work with luminance, as we have so far, then you would want to run through those same steps with the CMYK image. Those are a few tips and tricks for working with Curve Adjustments here inside Photoshop.
- Adjusting the color settings in Photoshop
- Placing and blending Smart Objects in a scene
- Transforming and warping vector objects
- Correcting for lens distortion
- Mitigating halos and enhancing contrast with Shadows/Highlights
- Adding and editing points on a curve
- Editing multiple images in Camera Raw
- Creating a pro-quality sepia tone or quadtone
- Colorizing with blend modes and opacity
- Reducing and smoothing over noise
- Creating depth-of-field effects with blur
- Selecting with Color Range and Quick Mask
- Perfecting a mask with Refine Edge
- Drawing paths with the Pen tool
- Converting path outlines to vector masks