I Like Curves: An Opinion

A recent discussion over my recent duotone tutorials have made me think about my attraction to Photoshop’s scintillating Curves.

I like Curves. I used to be a Levels kind of guy, and I still use Levels for some tasks, but for me Curves makes up the total package.

My recent thinking about Curves came about when Mike Anderson wrote in about my February 16 tutorial on creating a letterpress effect with duotones. I showed how you can use duotones, tritones and quadtones to create a letterpress effect using one, two or three spot colors plus black. Mike pointed out that it can be a lot easier to simply use a Gradient Map (Image –> Adjustments –> Gradient Map…) or Gradient adjustment layer to do the same thing. Two similar techniques, two similar final outcomes, but duotone building is based on a Curves interface while working with gradients in the Gradient Editor requires work with Levels.

Is one interface better than the other? I used Levels early on in my career to color-correct images—setting shadow and highlight points, working with midtones, that sort of thing—and it worked pretty well. Here’s a quick tip, if you didn’t know: the eyedroppers in the corner of the Levels dialog box can set your highlight and shadow points for you. Double-click the black eyedropper and enter the desired CMYK values for your shadow. Ditto for the white eyedropper and your highlight. Now you can click on your image’s shadow and highlight points with the black and white eyedroppers respectively and set those points to carry your preset shadow and highlights.

I like using Levels because it’s easy: click your black, click your white, move the middle slider until your image looks good and you’re done! And I still prefer to use Levels if I’m doing color-correction on the cheap or in a time crunch. I had even planned to write a tutorial on how to perform color-correction in 15 seconds.

But I didn’t write that tutorial and don’t plan on it (unless there’s an outcry for it). The reason is because I try hard to find the best tool or technique for a given situation, rather than one that’s quick and easy. Sure, if time is a constraint I have no problem using a shortcut to get the job done, but if it’s not then I like to use the best. (Whether there truly are “best” techniques for a given job is debatable.) My real love affair with Curves started a few years ago when I read Dan Margulis’ Professional Photoshop. By that time I had decided to really punch up my skills and techniques, and I had heard Dan’s book was considered the bible of its field. Two comments about Levels stuck with me:

And this one is more succinct:

Levels really is a curve with three and only three points, and in color correction I’m convinced that the greater control in Curves is the better instrument. To be able to control how colors change between those three points is vital, and Levels doesn’t offer that kind of control. Moreover, Curves allows the input of numbers for color information on a 0-100 scale, which is also vital when you are working with images in CMYK. Levels has numeric input too but it works on an 0–255 scale, which is based on the RGB color mode, and the midpoint can have a value of 0.10 to 9.99, which doesn’t make sense to me. Most of my images are eventually going to print, and color numbers are very important.

The Gradient Editor, however, is a different beast because it’s not modeling a value continuum (highlights to shadows) but about a color continuum (multiple colors across the span of the document or selection). You can add an unlimited number of color stops to a Gradient. What I’ve noticed though, is that between two color stops the Gradient Editor works exactly like Levels—all that can be manipulated is the midpoint, marked by a white diamond. Fortunately, in 99.99% of the cases this is all you’ll ever want.

But my conclusion is that Curves has an edge over Levels due to its ability to take on many points and accept numeric input based on CMYK. I want to hear from our readers though—what do you think is the better of the two? I know there are a lot of users who are very much in one camp or the other. You’ve read my story, now let’s read yours!