The Ultimate Quick Guide to Levels and Curves in Photoshop

Ever wonder what the difference was between adjusting the levels and adjusting the curves? Or wonder which one you should use? Or simply default to using the levels adjustment because the interface for curves seemed a bit daunting? If any of these are true for you, then take a look at the video below where photographer Joshua Cripps shows us how each of them works and why one is actually better than the other. Which one? Well, you’ll have to watch the video to find out:

The levels and curves adjustments in your editing software serve to adjust the brightness, contrast, and white/black points in your image. They work off of your photo’s histogram and allow you to change not just your RGB settings, but also your individual color channels. So what’s the difference?

Levels

Well, levels at first glance seems much more user-friendly than curves. The graph itself is very linear and easy to grasp, and there aren’t a lot of deviations from the scale–no strange “curves” in the straight line of your graph.

Curves

The interface for curves, on the other hand, seems a lot more daunting at first glance (it did to me, anyway). There are so many options with the various anchor points, that unless you know where the area of tonality you want to adjust stands on your diagonal line, making the adjustments can all seem like guess work. But the reality is, those micro-adjustments really give curves an all-around plus because they allow you to make only the adjustments you need, without affecting the rest of your image. For example, you can adjust your highlights separately from your shadows. Levels doesn’t reach this degree of specificity.

Setting Anchor Points With the Curves Tool

With the curves tool you can set anchor points, allowing you to adjust areas of your tonality without losing data.

But perhaps the best reason to use curves is that your adjustments do NOT cause you to lose data. With the levels adjustment, everything above and below the perspective end points is lost data. It’s just gone. In curves, because you don’t need to move the end points to make adjustments, you don’t have any image data clipped (you’ll still get posterization depending on the adjustment, but that happens in both tools).

As Cripps puts it:

“The real wonderful spot where curves absolutely stomps levels into the ground is with its ability to preserve highlight and shadow detail while still making tonal adjustments.”

It also happens that curves is actually more user-friendly (once you get used to it). If you don’t know where a tone lies on the graph, you can simply use the hand tool (circled in red) to click on any part of your image and drag the highlights up and/or the shadows down without having to know where on the line those tonal adjustments stand. Awesome, right?

Using the hand tool

The hand tool allows you to make adjustments to your image without having to know where your tone lies on the spectrum.

In the end, curves is the way to go for just about any tonal adjustments you want to make.

Don’t agree, or know other great reasons to use levels? Tell us about it in the comments below.

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