Photoshop tutorial: Curves tips and tricks | lynda.com

Photoshop tutorial: Curves tips and tricks | lynda.com

In this movie, I'll share with you a few tricksthat should make your life easier when working with curves.

You will notice that I've goneahead and renamed my layer contrast.

I'll double-click on it to bring up curves insidethe Properties panel, and just to make sure that I'm protected, because I am going tomake a bunch of modifications here.

I am going to go up to the flyout menu and choose SaveCurves 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 someplacein your hard drive and then click the Save button, and you'll see Black & white heftin my case listed among your Presets, which means you can come back to this graph anytimeyou like.

Now it's showing you how you can press the Control key or the Command key onthe Mac and click on a point in order to delete it.

I'll go ahead and press Ctrl+Z or Cmd+Zon 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 willreduce the number of gridlines.

And all that is, is a preference.

This is not a snappinggrid.

So it won't help you nail the location of points.

If you Shift+Click on points, youwill select multiple points at the time.

So I'm going to click and then Shift+Click onthese three points right there.

For example, I will drag them upward and typically thisis what you want to do.

If I were brightening the darkest colors for example, I would dragthese points upward or I could darken them by dragging downward.

You typically don'twant to drag back and forth, because in my case if drag to the left, I end up losingsome 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 resetthose 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 afew times in a row and notice that the Output value now reads 8.

That is not an absoluteluminance level as in almost black.

That is a relative luminance level meaning that wehave brightened all three of these points by eight.

All right.

So far I've showed youhow to set and modify points on a curve, but you can also draw a custom curve graph usingthis Pencil right here.

So for example I could go ahead and just draw a curve across thegraph 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'llend up inverting the image like so.

You can also draw crazy graphs if you want to.

I willgo ahead and turn off these two grayscale layers right there so that we can see curvesapplied to the full-color image, and now notice if I draw something along these lines, I'mcreating what's known as an arbitrary map, which among other things can end up generatingpsychedelic effects like these here, and you're probably not going to take advantage of thisvery often, but you may sometimes find these sorts of arbitrary maps to be useful whenworking with masks.

Now if your curve ends up having a bunch of gaps in it as mine doesor it ends up spiking in certain locations, you can soften the transitions by clickingon the Smooth button.

So notice each time I click Smooth, I end up smoothing out mygraph like so and then I could decide this wants to go back up and then I could clickSmooth a few more times.

Now a more practical way to take advantage of the Pencil combinedwith Smooth is to Shift+Click inside the graph.

Let me show you what that looks like.

I'llgo and turn those two grayscale layers back on and then I'll click in the bottom leftcorner and Shift+Click at this location here and Shift+Click again, and notice each timeI Shift+Click I end up connecting my click points with straight segments.

So that's aquick way to roughen a graph, that ends up giving us this posterization as you can seehere inside the image window, however.

So get rid of the posterization and smooth outthe transitions you click on the Smooth button, probably three or four or even five timesin a row.

Now the great thing about working this way is you don't have to mess with thevalues and Photoshop will actually create the values for you if you just go ahead andclick 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 thingto note, if I grab the Target Adjustment tool, I was showing you how if you move your cursorin the image, and my cursor is in the woman's forehead right here, you can see the bouncingball, in my case in the upper right portion of the graph and if you click, you end upsetting a point to that location.

Well, you also have three other graphs to work withwhen 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 compositepoint as we created just a moment ago, a channel by channel point.

So in my case, let's sayI move down her brow here so I can get a kind of darker color, and right about there I willpress the Ctrl+Shift keys or Cmd+Shift on the Mac and I'll click.

And that goes aheadand sets a point inside of each one of the independent channels.

So notice if I switchto the Red channel, I've got a point right there, and so I can press the Up Arrow keyto add a little bit of redness to my otherwise grayscale image and now I'll switch to theBlue channel and press the Escape key so that the menu is no longer active and press theDown Arrow key in order to achieve a kind of Sepia effect there, and then I might switchover 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 andI achieve this effect here.

All right.

Now I am going to switch back to the Compositeversion of the image like so, and you can see those channel by channel curves representedin Red, Green, and Blue inside the composite graph.

All right.

Let's end things with alook at what happens when you're working inside of a grayscale image.

So for the moment Iam going to go ahead and click on this Curves layer here inside the Layers panel, and pressthe Backspace key or the Delete key on the Mac to get rid of it, and then I'll go upto the Image menu, choose mode, and choose Grayscale and I will a get series of alertmessages asking me if I want to rasterize my Smart Object.

I do, so I'll click the Rasterizebutton.

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 thecolor information? I do, so I will click Discard and I am left with a single layer as wellas the single channel gray here inside the Channels panel.

Now if I dropdown to the Black/Whiteicon and I choose the Curves command, you can see here in the Properties panel thateverything is backward.

We have the white triangle on the left-hand side and the blacktriangle on the right side.

And the reason for this is these guys no longer representLuminance levels, instead they represent ink values.

So if I were to click on this lowerleft point, you can see that the value is 0.

By that it means 0% ink which is paperwhite and if I press the Plus (+) key in order to advance to the upper right point, its valueis 100 meaning a 100% ink, so black.

What that does is it ends up just messing withthe way your brain works inside Photoshop in my opinion.

I can go ahead and reload thatpreset I created a moment ago by choosing Black & white heft, but now the whole thingis upside down and backwards.

So I'm raising the points in order to darken those shadowsin the upper right region of the graph and everything that's occurring with the highlightsis in the down left region of the graph.

If you don't like to work that way then I haveto admit I don't, because everything else in Photoshop is based on luminance.

Then youcan click on the flyout menu icon and choose Curves Display Options and then switch ShowAmount of from Pigment/Ink% to Light (0-255) and that restores the graph to its more familiarbehavior.

Then click OK, and by the way, this will change the graph for all future grayscaleimages as well.

If you work in CMYK and you prefer to work with luminance, as we haveso far, then you would want to run through those same steps with the CMYK image.

Thoseare a few tips and tricks for working with Curve Adjustments here inside Photoshop.

Source: Youtube