Use a levels adjustment to alter the lightness or brightness of your image. Adobe Tutor Sajid Holy teaches a technique for using the levels histogram to visually adjust the dark and light areas of your image to create greater contrast. Use a levels adjustment to alter the lightness or brightness of your image. Lesa teaches a technique for using the levels histogram to visually adjust the dark and light areas of your image to create greater contrast. Use a levels adjustment to alter the lightness or brightness of your image. Lesa teaches a technique for using the levels histogram to visually adjust the dark and light areas of your image to create greater contrast. Use a levels adjustment to alter the lightness or brightness of your image. Lesa teaches a technique for using the levels histogram to visually adjust the dark and light areas of your image to create greater contrast.