This technique is a contrast/tone and color correction technique all in one. Once you run through this technique, you will see how just about any image can be improved and you will use this technique many times over
1. As you can see the image is lacking a bit of contrast and also has a bit of a color cast to it. Its really not that bad (or is it?), just looks a bit dirty. You will see a huge difference really soon.
2. Choose a Levels adjustment layer from the layers palette
3. We are now going to set the black and white points in the levels settings
4. In the Levels dialog box double click the Set Black Point tool as shown in Figure.
5. You will see a color picker, set everything to solid black and them change the setting under “B” to 5 as shown in Figure. (This sets the black point to 95% black)
6. Click OK
7. Double click the Set White Point tool, which is the white eyedropper.
8. In the color picker, set for pure white and then enter 95 into the “B” setting as shown in figure. The white point is now set to 95% white
We are now ready to perform the image correction, what we are going to do is click the Set Black Point tool, in the darkest part of the image and the Set White Point Tool in the lightest part of the image.
9. Locate the Darkest part of the image. Hold down the alt (Option on Mac) key and move the shadow slider in to the right, the image should turn white, as you slide the slider you will begin to see some areas begin to show through. This is the Black point threshold as shown in Figure. The areas that start to show are the darkest areas of the image.
10. Take note of where the dark portion of the image are on the threshold and return the slider to the far left.
11. Choose the Set Black Point Tool and click on the darkest portion of the image in the main image window as shown in Figure.
12. The image will be shifted and the area we clicked on will now be set to the 95% black that we selected in step 5.
13. Hold down the Alt (Option on Mac) key and move the right slider to the left to reveal the whitest point of the image. The image will be gin as black and the highlight areas will show through as shown in Figure.
14. Choose the Set White Point Eyedropper tool from the Levels palette
15. Click on the whitest area of the image as shown in Figure, the lightness of the image will be adjusted to match.
The tonal qualities of the image will be looking much better now and the color cast will be reduced a bit. Now to totally remove the color cast.
16. Choose the Set Gray Point eye dropper from the Levels dialog box
17. When we click on the image with this tool it will choose the selected area as the gray point of the image and balance all the color to match.
18. Click on a portion of the image that should be a neutral gray such as the small tower in Figure.
19. The colors will shift, if you are not happy, keep experimenting by clicking the Set Gray Point Tool in different parts of the image.
20. When you are happy with the result, Click OK to apply the Levels to the image.
You have now learned how to use the Levels tool correctly, it may seem like a lot to do, but with some practice you can perform this entire correction in under a minute. Figure shows the final corrected image, it is a vast improvement from the original.