How to color correct a portion of a photo?

Question

I am new to photoshop. I have version cs5. I have several photos that were taken through a Blue tinted plexiglass window.
Some or all of the photo has acquired the tint. Also parts may have a reflection minor of people standing around.
How do I remove the tint?
Please be as specific as possible.
Thanks for the help.

Answer 1

Bill Hunt wrote:
One comment, when shooting through any window/transparent object is to shield the area, that you are shooting through, so that there are no reflections. This technique is used, when shooting through "the glass" in a hockey arena. There are even special lens shades, that look sort of like a small lightbox, that fit up to the plex, but still allows one to alter the angle (a very flexible connection near the lens' outside mount). Now, that will not affect the "tine," unless that is coming from behind the plex, like a reflection of the sky.
Good luck,
Hunt
I carry a rubber lens hood that fits up against the glass.  An almost essential accessorie when visiting places like zoos.  You can even get away with using flash!
ibuster, your image is not an easy fix being quite so blue as it is, and with it being local to only some of the image, you are going to need to understand Layer Masks.
A good first step is to go Image > Adjustments > Match color  and click on Neutralise.
It is probably going to be easier to use Levels adjustment layers rather Curves, so
Open a Levels adjustment layer
select the Lasso tool, and click on one of the corners of the blue tint.
Hold down the Alt/Opt key, and click on the next corner, and so on until your selection surrounds that segment of blue tint.
Now do the same for the next blue segment, but hold down the Shift key for the whole time you work round the segment.  This will add this segment to your previous selection
Repeat for the other blue segments.
Now click on 'd' to make Black your forground colour, make sure the Levels adjustment layer is selected, and go Alt backspace (Opt backspace if using a Mac)
This is actually the opposite of what you need to so go Ctrl/Cmd d to turn off the selection, and Ctrl/Cmd i to invert the selection.  Your adjustments will only affect the blue segments now.
Right.  It is not easy to give you a step by step here, but a good first step would be to drag the end points of the Levels adjustment layer in a wee bit from both ends to restore the contrast to the blue segments.
Now make a decision on which of the Red, Green, Blue channels is out of sync, and use the drop down to select that channel.  Place your cursor over the 1.0 in the center of the Levels, and using the cursor keys, nudge its value up or down.
I am afraid it is not an easy fix, and you will be messing around for a while, and probably never get a perfect result, so good luck to you.  As you can see from my quick fix, the problem is not uniform across the segments, and would take multiple adjustment layers and careful masking to get a really good result.   I am not a Retouch expert either, so there may be easier ways to fix it - www.retouchpro.com would be a good place to ask for specialist expertise.