If you select any part of an image using any selection tool, you can
ignore the selection if you want and apply the effect on the whole
image. Applying effect only on the selection may create interesting
effect. We will try using selection in this lesson.

1. Open Photoshop CS.
2. Open Island Girl.jpg from the samples folder of Photoshop CS
directory.
3. Using Rectangular Marquee Tool, select the middle area of
the image including girl.
4. Go to Image > Adjustments > Match Color
5. Please make sure that the Preview option is checked.
6. Select Ignore Selection when Applying Adjustment.
7. Drag Color Intensity slider to 1.
8. Observe the image (Island Gril.jpg) carefully.
9. The image is changed into gray scale.
10. Now deselect or uncheck Ignore Selection when Applying
Adjustment option.
11. You will notice that only selected rectangular area is
remained grayscale.
12. Try different options using selection.
13. Please do not save the image.