I am a total noob in photoshop and basically what I want to do is to change some colors of flags, for example to change red color to white and white to red, I can easily do that with the color replacement tool, but the problem is that the brightness or something is way too bad, for example I want to change red to white and in the end I get a gray color, instead of the white that I chose as a replacement color, so how do I change the brightness of that specific part?
There are some other details, like the flag being curled up a little, which means that there are shadows and variations in the brightness, so I don’t want to just draw a pure ,flat" white color, but to make it look realistic, the only problem is the end result being too dark and me getting a gray color instead of white.
It’s a complicated process to get exactly right. You’re on the right track with the color change tool. You also need to manipulate the fuzzyness slider and the hue, as well as fine-tune a couple of places in the image. This video is a pretty good guide (he uses a car, but it’s the same principle). Also look at this tutorial from Adobe.
First, of course, select/make an alpha channel of the red part you want to change to white.
Then, once that part is selected, try using the Black and White Adjustment Layer, and swing the red slider toward the white end. It’ll desaturate the red, but also brighten it as you slide it. You should get to the point where the shadows are maintained, but still looks white and not gray.
That should get you most of the way there. From that point, you can try using Levels or Curves to lift or darken certain areas.
I doubt a ps noob is going to be making alpha channels.
Use selective color, not color replacement. When the dialog box appears select the red in the image you want to effect, using the pointer. Now slide the saturation all the way down. Then use shift+click on any other red from the image you may have missed from the first selection you made. You can continue to shift+click until you’ve selected all shades of red. This option allows you to effect hue, saturation and brightness.
An alpha would open up more options but selective color will work very well.
using photoshop, as a quick alternative, one could also change the image from it’s native-color to greyscale … change it back to native-color … and add “colorization”.
could also bring it into illustrator and vector the image (using image-trace feature) … then apply color as desired. nice thing about vector is the control/rendition of the resultant media. however … the vector approach can be a bit time consuming … 'specially for the faint of heart.