Adjusting colors with Curves

[southwestform]

I'm new to Curves and am experimenting with an image by adding blues to the darkest point by pulling up on it and now I want to add some orange to the highlights to create the complimentary orange/teal look.

1. is the lowest dark point on the left that I pulled up on considered the shadows or the blacks?

2. how do you add orange to the highlights? Is there anyway to get orange or do you just work with hues that are somewhat close? Do I just switch to the red channel and pull up somewhere along the curve inside the top right square?

3. should the RGB curve be manipulated after working with the individual R,G,B channels or before or does it not matter the order?

Thanks!

[Chuck Uebele · Accepted solution]

1. Yes, the lower left is the shadows - most of the time. Sometimes the curves can be inverted, so make sure by moving one end of the curve so see what happens. Pulling up on the curves will lighten that channel, so if it's the blue channel, it will lighten and add blue.

2. to add orange in the highlights, you have to adjust both the red and blue channel. Pull up on the right side of the red curve to add red. Pull down on the right side of the blue curve to add yellow.

I would adjust the RGB curve after, as each channel adjustment will affect the brightness of the image.

[Semaphoric]

If you are pulling up on a point that has an input value of zero, that would be the blacks. If you pulled up a point somewhat to the right of it, that would be the shadows. It depends on the effect you're trying to achieve. The first way, the blacks will go blue, but with the second, the blacks will stay black, and the shadows will go blue.

Regarding question two - Orange is between Yellow and Red, and the complement of Yellow is Blue. You want to add Red and subtract Blue, so you move the upper right of the Red channel up/to the left, and move the Blue channel down/to the right.

I usually adjust the RGB first, but some people work only on the color channels, ignoring the RGB adjustment altogether.