Using Curves to make a change to a specific portion of an image

[media kat]

1. How can I make a selection to an image using a selection tool and use a Curve Adjustment Layer to manipulate only the selected area? When I try this it does not seem to apply the change to only the selection.

2. As an alternate approach, if I want to adjust the brightness/darkness of a specific area of an image how can I just use the hand tool to select the area I want and drag up or down? Doing this seems to be making the change to whole image.

Thanks.

[michelew83603738]

You should be able to make a selection of the area with any selection tool. Here I just made a rectangular selection over part of the image and go to the curves adjustment.

Then you make your adjustment and it creates the adjustment layer with a mask over the part of the image you don't want affected.

You would use the same process for the brightness/contrast adjustment layer, but I am not sure what you mean by the hand tool.

[davescm]

The "hand" tool within curves just helps you to pinpoint a particular point on the curve by clicking on the image and gives a convenient way to adjust the curve by dragging upward /downward on the image. It does not restrict the change to a particular area within the image .  To do that you need to use a mask with your adjustment layer , as shown by michelew83603738 above.

Dave

[michelew83603738]

Yes, but media kat was asking about a hand tool in the brightness/contrast adjustment layer - there isn't one that I am aware of. Are you?

[media kat]

I was referring to the hand with a finger in the Curves Panel. Somehow making the selection was not working previously, though now it does with the mask.

Thanks!

[media kat]

One other question: I go to the R channel and use the hand with the finger to target a specific area on the photo and press Command + Shift so that it places a point on my Curve in the same spot on the G and B Curves, so I can adjust the same exact portion of the image for each channel. However, when switching to the other channels, the point seems to appear on a different part of the Curve for each channel. Why is this?

[davescm · Accepted solution]

Unless the area of the image that you clicked on is perfect black,  white or a grey where red = green = blue , then the point value will indeed be different on each curve.

Dave