To adjust the tone curve on your image, choose a tone curve (use your chosen preset from the tone curve palette) click and hold the green slider for two seconds, then move the slider until the white at the right end of the slider matches the white at the left end of the slider. Change the color of a selection in Mac Preview and preview with a white background Dec 15, 1999 — The Color Correction in Preview App Can Replace The Need For Lightroom To take more control over the color adjustments of your images, you can use the color correction tools in Preview on Mac. In order to improve the color, you can use the tools with black & white images instead of color images. 1. Open a photo and click Layers > Layers… or go to the menu bar and click Layers 2. Click the Filter tab on the top right 3. Use the sliders to adjust the color of the image and remove any yellow, or add any green or blue by clicking the yellow slider to the right of the green slider 4. Press the C... button to make the adjustment permanent and click OK to return to the main tool menu 5.