Quick Photo Color Correction with Preview on Mac

Preview: A Powerful Image Editor on Your Mac
The Preview application, included with every macOS installation, is a surprisingly capable image viewer. It stands out as one of the most feature-rich default viewers available to users.
Finding an image viewer that satisfies everyone can be challenging. Windows users often debate the best options, as the built-in alternative frequently falls short. Preview, however, avoids this issue by offering a wide range of functionalities.
Beyond Viewing: Preview's Versatility
Preview isn't limited to simply displaying images. It allows users to combine and edit images into a single PDF file, and also provides convenient batch resizing capabilities.
Performing quick color corrections is another valuable task achievable within Preview. This is particularly useful when you wish to avoid installing additional software, or when only a few images require adjustments.
Initiating Color Correction
To begin color correction, open the desired image within Preview. Navigate to the Tools menu and select "Adjust Color," or utilize the keyboard shortcut Command+Option+C.

An instant adjustment can be applied by clicking the "Auto Level" button. Alternatively, the triangle sliders located beneath the histogram offer more precise control.

Fine-Tuning Your Images
The Exposure, Contrast, Highlights, and Shadows controls allow for fundamental adjustments that most images benefit from. While not every image requires all these changes, subtle improvements to exposure and contrast are often possible.

Selecting the eyedropper tool enables automatic color correction by identifying a neutral point within the photo, such as a white or gray area. For finer adjustments, utilize the Temperature and Tint sliders.

Black and White Conversions & Sharpening
To convert an image to black and white, slide the Saturation control completely to the left. Further color adjustments can be made using the Temperature, Tint, and Sepia controls.
If your photo lacks sharpness, experiment with the Sharpness slider. However, be cautious, as excessive sharpening can introduce unwanted artifacts. Conversely, dragging the slider to the far left creates a soft, dreamy effect.

Feel free to experiment with the various settings to transform a lackluster photo into something visually appealing. All changes are non-destructive until saved, eliminating the risk of irreversible errors.
If you wish to revert to the original state, simply click the "Reset All" button at the bottom of the color panel.
Related: How to Combine Images into One PDF File on a Mac
The next time you encounter a photo that needs improvement, open it in Preview and make the necessary adjustments in minutes, without the need for additional software or complex image-editing programs.