I like the image but I want to change the kinda blah blue color on the right to make it a lot more like the blue on the left. I tried a hue/saturation adjustment layer and picked blue, then moved the slider to the right to make it a prettier blue. BUT, when I do this, the almost-magenta blues become magenta, and the tree looks like it's covered in magenta christmas lights. UGH. I tried adding another layer of the blue on the left and trying to blend-mode it in, or to multiply it in, and these didn't work. Anybody know a better way? thanks--
I would make a curves layer set to luminosity, and brighten up the right side of the picture. Then invert the mask of that layer to black and brush back in the right side sky of the image with a white brush.
Then I'd make an HSL layer, copy the mask from the first layer to this one. Select the blues and crank the saturation and push the hues to the right a bit.
Try "Replace Color." You can select the entire blue sky and replace the different blue tones with a single shade of blue.
thanks for your input... everything I tried came with unwanted issues, like light-blue haloes around the dark-tree branches, or erasing half the stars. I ended up with a curves layer that dropped the less-bright green to zero, but it had its issues too. there just wasn't an easy way.