Sometimes we must control the area of effect. For example, imagine these 2 images combine. I want to use old man’s head and a young man’s body.
Pay attention on the direction of the light.The light comes from the right in the old man’s image, and comes from the left in the young man’s image.
The above image is just a combination of 2 images. The most problem is the difference of the light and shadow. It is odd. So I need to add the adjustment layer.
In this case, I used Hue/Saturation as the adjustment layer.
By the way, If you want to affect the adjustment layer’s effect only on the below layer, choose Create Clipping Mask. You can just click the below icon to create Clipping Mask.
I decreased Saturation and Lightness both and I got the below image.
I wanted to put the new effect only on the left side, but the new effect was put on all side. I must restrict the area of the effect.
Choose the layer mask of Hue/Saturation and push Ctrl button and ‘I’ button at the same time. It means the inverse of the effect. Layer mask becomes Black from White.
After this, Choose White Brush and paint only the area which you want to put the effect. You can get like this.
All process can be seen in the below GIF.