Recently in a number of my one-on-one training with clients, they asked me about adding contrast to a photograph and the differences between adding it using the Contrast slider and Curves tool in Capture One Pro 20 (CO20). I thought the answers might be helpful for some of our readers, so in this article, I’ll share some of what I shared with them.

The first thing to talk about is contrast and why we add it to a photograph. Basically adding contrast adds life and impact to a photograph. And while it is changing the relationship between the dark and light areas of a photograph, it’s also changing the underlying texture, sharpness, and saturation as well.

Next since both the Contrast slider and Curves tool give me the ability to change the contrast in a photograph, what are the differences?

Contrast slider

  • Speed: Fast and simple to use and can be very effective if you have a large number of photographs to edit.
  • Clarity slider: You will want to use the Clarity slider as well as the Contrast slider to address the mid-tones in the image.
  • Quality: It does a good job of adding a fixed amount of contrast to the image.
  • Flexibility, accuracy, and control: Not very flexible when compared to the Curves tool, also limited accuracy as it adds or subtracts a fixed amount of contrast.
  • Saturation/texture/sharpness: As the Contrast slider setting is increased or decreased it adds or subtracts a small amount of saturation in the affected colors. It also affects the texture and sharpness in those areas as well.
  • Learning curve: Fast and easy to learn.

Curves tool (RGB tab and Luma tab)

  • Speed: It takes more time than the Contrast slider, though as you learn it, you’ll get faster.
  • Clarity slider: I often find that I’m able to create a similar look using the middle area of the Curves tool, but there are times when I use both.
  • Quality: Typically this will give you superior results over the Contrast slider.
  • Flexibility, accuracy, and control: It gives the most flexibility, accuracy, and control over the image through the use of multiple points along with the entire range of the curve from darkest to the lightest area of the photograph and you’re able to move each point on the curve independently.
  • Saturation/texture/sharpness RGB tab: Changing the curve using the RGB tab will add or subtract saturation and change the texture and sharpness of the affected areas.
  • Saturation/texture/sharpness Luma tab: Changing the curve using the Luma tab doesn’t change the saturation of the affected areas just the luminance and it will change the texture and sharpness of the affected areas.
  • Learning curve: Longer than the Contrast slider. It takes practice and understanding to master the Curves tool.

In the sections below, I’ve included examples of the original image and versions using the Contrast slider and Curves tool, so you can see the differences.

Original image

So now let’s take a look at these two with a photograph. Here’s the original image without contrast or curves applied.

Contrast slider

Here’s the same image using the Contrast slider only. This was the most contrast I could apply to the image without making things too dark and it still doesn’t look the way I want. So for me, this image isn’t a good choice for the Contrast slider.

Curves tool using RGB tab

Here’s the same image using the RGB tab of the Curves tool with the Contrast slider set to zero, compared to Contrast slider only. Notice how I can add multiple points to fine-tune the contrast both up and down through the range of the histogram.

Also notice that I raised the level in the left or dark side of the curve and lowered the level in the middle part of the curve. This ability to add the points and then slide them up and down is what gives the real power to the Curves tool. I almost always use the Curves tool on landscapes and cityscapes because I want this kind of control over the final image.

Curves tool using Luma tab

Here’s the same image but using the Luma tab of the Curves tool only and the Contrast slider set to zero.

The power of the Luma tab in the Curves tool is that it is changing the contrast, but doesn’t change the saturation level in the affected colors. With this, we are just changing the light or luminance values. There are times where I only use the Luma tab and not the RGB tab or use a combination of both to achieve the look I want.

Curves tool – Luma compared to RGB

Now here’s the Curves RGB compared to the Curves Luma. Notice the changes in saturation in the RGB version compared to the Luma version.

Final thoughts

When I use these tools in my editing, I have an idea of what I want from the final image. I also look at my time frame, the number of photographs that I need to edit and then I choose the tools that can help me accomplish that.

What I found with this image — the lead photo at the top of the article — was that using both the RGB and Luma Curves instead of the Contrast slider, gave me the best result. More generally though I find that if I want complete control over the look and feel of my image, I’d use the Curves tool, and often both RGB and Luma tabs.

Is it worth taking the time to learn the Curves tool? I’d say absolutely.

Do I use the Curves tool for everything? No.

If you haven’t yet, be sure to check out this new version. You’ll find a 30-day free trial to Capture One Pro 20 here.