Intro to the Curves Tool

Rachel Johanna

Product Photographer & Marketing Maven

A few weeks ago we released the newest version of Camera+ 2! This update includes a few new features but one of the best is Curves in The Lab. Up until now, curves has only been available in Raw Adjust.

A must have tool for editing your raw images, curves has always been my favorite tool. It’s awesome to now have the option in The Lab. This gives you the ability to use curves on images shot in Macro mode or with the front facing camera. It also opens the world of tonal values to anyone not ready to get their feet wet with raw shooting.

If you are familiar with curves then go forth and concur the S curve. But if you are new to it, stay tuned, I am going to give you a little tutorial so you can see what all the fuss is about!

Why Curves?

There are so many great tools available in both The Lab and in Raw Adjust. Curves allows you to expand on those edits and have more control over your adjustments. Which sounds great right? But also intimidating! It can be really overwhelming to have so many options. But don’t let that stop you. I still feel that sometimes and I’ve been using curves for years!

What Does Curves Do For You? 

Curves is kind of a do-it-all tool. You can add or subtract contrast, you can change the highlights & shadows, you can make the blacks more black, and you can change the intensity of the whites. 

For example you might be able to save the details in a blown out highlight or make your overall image more rich by changing the black level.

Getting to know curves. 

Above: The Curves Tool in The Lab

Curves starts as a diagonal line on an axis that represents the values of your original image. On one end of the line – the left – you can manipulate the black levels. On the other – the right – the white levels.

Above: The Curves Tool in Raw Adjust

Next you’ll wanna start moving points. The amount of points will depend on the choice you make. You get 3 options in raw adjust and 2 in the lab.

As you move these points the line changes and becomes, well, curvy

Sections that are steep create high contrast and flatter sections are the low contrast spots. 

Understanding the Histogram

Behind the curves axis you will see what is called a luminosity histogram. It represents the same values as your curves line – dark values on the left and bright values on the right. Your histogram represents the pixels of your image and how they are distributed.

As you move points along the axis the pixels will be redistributed and you will see the histogram move to represent that.

The reason it is so helpful to have the histogram here behind the line is because it can help you determine whether parts of your image have enough data to make corrections. Before you start moving points you will be able to see what your image needs.

For example:

This histogram shows my image has a good amount of pixels in the darkest points but not very many in the brightest. I might use this information to redistribute pixels to the right and save some of the brightest parts.

How Do I Use Curves?

Well, technically, it is simple – you just tap a point and drag. 

Dragging a point up will lighten the area and down will darken it. Going left or right changes the intensity of the contrast. 

I think it would be best to show you some practical examples so you can see how it really works. 

A Few Examples

Brighter and darker

The first thing you want to try is the most basic. Brighten & darken your image by moving points up or down. When using a 3 point line, moving the midpoint will brighten or darken the full image. When using more points, moving a point vertically will only affect the section it is in.

Black and white slide

Adjusting the black & white levels are one of the simplest things you can do with curves. Simply drag the bottom point to the right and you will see the dark areas get darker. Drag the top point to the left to brighten the whites or you can drag it straight down to darken them if they need it.

Matte Black

That matte black look is very trendy. Let me show you how to create it. Take that same black point and drag it upward. You will see the blacks start to fade. Drag till you like the look. Pro tip: if you drag this point higher than the midpoint the dark areas might start to look a little weird.

S curve 

The S curve is a well known technique. It’s known as a go-to for editing photographs and improves most images. Creating an S curve is simple. Choose the 4 point option and start dragging. The second point from the left should move down and the second from the right should move up. This is going to create richer tones in your image. Your colors will have more depth. It’s a great tool. I apply an S curve to almost every professional photo I take!

Complex- save the whites and rich blacks

Let me show you something a little trickier. I took this image of a white daisy in bright sun and the petals were really blown out. The shadows were washed out too. I chose the 5 point option because I knew I needed as much control as possible. First, I dragged the white point down to save those petals but that wasn’t quite enough so I pulled the next point down as well – just watching the info in those petals until I achieved the right look. Then I just needed to attend to the dark spots in the images that look faded. I’ve already showed you how to darken the blacks. I could have used that technique here but instead I pulled the point second from the left down a bit. This move darkened more than just the blacks – it affected the midtones and blacks but didn’t affect anything above the midpoint. This kept the changes I made to the petals safe.

I hope this quick tutorial gives you the confidence to try out the Curves tool. Don’t let it intimidate you. The best way to get to know curves is to experiment with it. Try it out on your next edit. You can always reset the curve and start again.

Stay curvy!

Check out our video about curves here.

Published by Rachel Johanna

Product Photographer & Marketing Maven