How to Use Color Picker in GIMP

GIMP has gained a bit of a reputation as a program that can be very difficult to learn, and sometimes even the simplest tools can be surprisingly complex when you’re just starting out. 

The Color Picker tool, often known as the Eyedropper tool in other image editing apps, is a perfect example of how a simple tool can have a surprising amount of depth – and how it can be invaluable to your workflow. Let’s take a closer look at how it works! 

The Color Picker Tool

The Color Picker tool does exactly what the name suggests: it allows you to select colors from pixels in your current document. You can use the picked color as a foreground color, or a background color, or add it to a color palette that can be used to streamline the rest of your workflow. 

For reasons that are not immediately clear to me in this digital age, this same tool is usually named the Eyedropper tool in other image editors (like Photoshop), which makes this one of the few cases where GIMP’s naming system makes more sense than the rest of the apps out there. That being said, GIMP still uses an “eyedropper” icon to represent the tool in the Toolbox, as you can see below. 

Click the Color Picker icon in the Toolbox to activate the tool, or switch to it using the keyboard shortcut O. 

Using the tool is as simple as a single mouseclick in the right place, but it’s important that you have your options configured correctly, or you might get a confusing result.

Color Picker Options

When any GIMP tool is active, the Tool Options panel just below the Toolbox will display some key settings that have a huge impact on how the tool functions.

By default, the Color Picker will sample a single pixel and then display the color information and a swatch in the Color Picker info window – but it can do a lot more than that. 

Sample average

By default, the Color Picker tool only samples a single pixel, but this setting allows you to set a larger sample area. 

When enabled, GIMP adds a Radius slider in the Tool Options for specifying the size of the sample area. Then it averages the colors across the entire sample area to generate the final result. 

It probably shouldn’t be named “radius” since GIMP displays the current sample area size as a square centered around the cursor (as you can see above), but at least you can get a quick preview of the sample area by moving the cursor around over your image. 

This setting is especially useful when picking colors from high-resolution photos since single-pixel samples don’t always match accurately with the color gradients in photographs, but don’t set the sample size too high! 

Sample merged

This setting only applies to images with multiple layers, and it tells GIMP to sample all the visible layers at your click point as though they had been merged into a single layer. 

This is useful for sampling composite images that contain layers with transparent pixels, but it has no effect on a single-layer image, so it’s usually best to leave it enabled unless you specifically need to turn it off.  

Pick Target

This setting allows you to specify what you want to do with the sampled color:

• Pick only. This setting displays the color in the info window if enabled, and nothing else. 
• Set foreground color. This automatically sets the current foreground color to match the sample color. When selected, you can hold down the Ctrl / Command key to temporarily switch to set the background color instead. 
• Set background color. This automatically sets the current background color to match the sample color. When selected, you can hold down the Ctrl / Command key to temporarily switch to set the foreground color instead.
• Add to the palette. This setting adds the sampled color to the currently active color palette (see the Making Palettes section for more info on using color palettes).

Use info window

This setting specifies whether or not the Color Picker info window will be displayed, and it can be toggled on or off by holding down the Shift key while clicking on your image with the Color Picker tool. However, if the window is already visible, this will not automatically hide it – you still have to close it manually if you want to get it out of the way. 

The Color Picker Info Window

When the Use info window setting is enabled, clicking anywhere on your image with the Color Picker tool will also open the Color Picker info window, as shown below. This is a handy little info panel that gives you technical information about your sampled color using a range of different color space options, including the ability to show two different color spaces at once.

Helpfully, the info window also displays the Hexadecimal color code used by web browsers, as well as the X and Y coordinates of the sampled pixel. If you’re sampling an average area using the Sample average option, it will display the coordinates of the center pixel. 

To change the displayed color space, open either dropdown menu and select your chosen colorspace. 

A bit surprisingly, the Color Picker info window even includes the option to view the color data breakdown in the CMYK color space that is used for print work, even though GIMP doesn’t actually support images that are saved in CMYK without help from a third-party plugin like Cyan. 

If you don’t like having the Color Picker window docked in the upper right corner of your image, you can click the “Eject” icon located next to the close icon, and GIMP will convert it into a separate window which you can reposition anywhere you want, as shown below.

Interestingly, this popup version of the window also includes a Help button which isn’t part of the overlay version.

Making Palettes Using the Color Picker in GIMP

Last, but certainly not least, is one of the most useful features of the Color Picker tool: color palettes. 

Unfortunately, it’s not immediately clear how to use the Add to palette option because if you just enable it and start clicking, GIMP will automatically load the Color History palette into the Palette Editor – but Color History is a special palette that doesn’t function the same way as other palettes, so the whole thing can seem pretty useless at first. 

Instead, open the Windows menu, select the Dockable Dialogs submenu, and click Palettes. The panel opens in the upper right corner of the GIMP interface by default, and it displays a range of pre-made palettes as well as a few buttons along the bottom. 

Click the Create a new palette button at the bottom of the panel, as shown below. 

This will create a new palette and immediately open it in the Palette Editor panel. 

Give it a descriptive name, and then return to your image and the Color Picker tool. Now, as long as you have Add to palette enabled, you’ll create a new color swatch in your palette every time you click. 

A Final Word

That covers everything you need to know about how to use the color picker in GIMP! While it’s a relatively humble tool, it’s one of the most useful tools you can have in some projects. 

Whether you’re making a seamless patch to cover up an unwanted image element or you’re creating a color palette to use in a pixel art masterpiece, the color picker is one of those essential tools that you’ll come back to again and again – so start practicing!

Enjoy your color picking!

I’ve been working with digital images since the year 2000 or so, when I got my first digital camera. I've tried many image editing programs. GIMP is a free and powerful software, but not exactly user-friendly until you get comfortable with it, and I wanted to make the learning process easier for you here.