Working with color can be one of the most difficult aspects of image editing, but it can also be one of the most rewarding.
Whether you’re trying to create the perfect neutral color balance or if you want to splash colors all over the place, the colors of your image can have a dramatic effect on the overall tone and feel of the image.
GIMP has a number of different color tools available and even has an entire menu dedicated to them, but the simplest way to adjust the color balance in GIMP is by using the Color Balance tool. Shocking, I know!
To get started, load up your image in GIMP, and then open the Colors menu and click Color Balance.
GIMP will open the Color Balance dialog window, which allows you to fine-tune the color balance in your image to achieve the effect you want. You can make this a subtle adjustment that acts as the finishing touch to edit, or you can push the sliders heavily and create some interesting color effects.
Start with the Select Range to Adjust section, depending on whether you want to adjust the Shadows of your image, the Midtones, or the Highlight areas.
When the area you want to edit is close to the division between one of these categories, you may have to experiment a little bit to find the correct tonal adjustment category.
You can adjust the color balance for Shadows, Midtones, and Highlights individually, which allows you to tint shadows very differently from highlights and create some dramatic coloration effects.
You can also replicate the unusual color balances from different types of film stock, although there are no presets in GIMP that might help speed up the process.
Once you’ve selected your adjustment range, it’s time to move on to the Adjust Color Levels section.
(I’m not sure why this one area of GIMP spells it Colour instead of Color, as you can see in the screenshot above, but I’m going to stick with the American English spelling for consistency).
Since your RGB image is made up of three color channels – Red, Green, and Blue – there are three color sliders. If you reduce the Red slider into the negative range, you’ll be increasing the amount of Cyan, and the same goes for Green / Magenta and Blue / Yellow.
This can make it a bit tricky to balance colors at first until you get the hang of things, and this is one area where a bit of hands-on experimentation can really help you to understand how it all works.
For example, this photo of mine showing a Great Egret in flight looks a bit too blue, but I can adjust that by adjusting the Midtones and Highlights tonal ranges towards magenta and yellow.
Even just a slight adjustment of -2.0 Green and -8.0 Blue on the Midtones range has a visible effect. The results are most noticeable in the cloudy gray background, but the bird’s feathers are also more neutrally tinted than before.
As I mentioned earlier, you can also throw caution to the wind and push the sliders to the extreme ends of their range. Once you move any of the sliders past about 30 or -30, the effect is extremely noticeable, as you can see below.
It’s possible to create some truly beautiful color effects with a few adjustments of the sliders, but it’s far easier to turn your image into a brightly-toned mess. You’ll have to test this out on your own images to develop a more intuitive sense of how each slider will affect your image, but now you know how to get started, so start experimenting!
A Word of Warning About Color
Before you start spending huge amounts of time comparing the differences between your different color channel balances, it’s important to remember that the specific monitor you use can have a huge impact on how colors are displayed.
While an image might look perfect on your desktop computer monitor, it might look completely different when displayed on your laptop screen. If you’re not careful, this can ruin a lot of hard work!
The only way around this problem is to use a color calibration device to ensure that your monitor is displaying colors correctly. If you’re serious about getting the best possible results from your GIMP color balance editing, then a properly calibrated monitor is essential.
These devices plug into your computer and place a camera over your screen, while software displays specific colors and measures the difference between the color displayed on your monitor and the expected color. A calibration profile is generated that adjusts for the difference, and you can relax knowing that you’re seeing the true colors of your images.
Color calibration devices can be expensive, ranging from around $100 to thousands of dollars for professional-quality equipment, but you can get good results from the cheaper end of the spectrum as well, such as the Spyder X Pro that I use.
It’s the cheapest option from Datacolor, but apparently, all the price tiers use the same physical device, and only the software control is enhanced in the more expensive packages.
Even a cheap color calibration device is usually better than none at all!
A Final Word
That covers everything you need to know about how to adjust the color balance in GIMP!
You can make subtle, refined adjustments to give your photo the perfect tone, or you can go wild with the adjustments and create something dynamic and dramatically colorful.
Now that you know what to do, it’s up to you to make something uniquely your own.
Happy balancing!About Thomas Boldt