hello mates,
i have a dell st2421l in our studio, took it from my desk at home to provide space for my benq, now i work on it from the studio, i noticed that the color gamma in the lower half of the screen is actually higher than the top half, now i though i might look for some sort of a tool that changes gamma in a certain region in the monitor, if that is even possible...
 
it is quite unnoticeable, i can only spot the difference when i open up two windows of the same image and compare them by dragging one to the top and the other at the bottom, almost impossibly noticeable from normal usage, but before throwing away that dell "or using it as a cctv monitor" i thought i might find a solution from you guys about the gamma issue, i do some mapping and modelling on it, colors are not that important in this case, but if it can be fixed why not fix it? 
 
Thank you for reading my thread, any help would be greatly appreciated.

Hello Cpt.Vance,
When running a calibration tests for your monitor (specifically on the color black) do you notice a backlight bleed effect? This is essentially excess light that is bleeding around the edges of the LCD panel that causes discoloration on different segments of the monitor. There is no definite fix for backlight bleeding other than dismantling the monitor and adding black electrical tape around the LCD panel to block out the backlight from bleeding through (which I highly advise against, unless you feel comfortable doing so). You may also want to make sure there is nothing magnetic by your monitor, this too can cause discoloration.

Cpt.Vance,
It is very possible that it could be a bad cable or even a damaged port, Keep us updated with your results.

thank you for your suggestions but nothing seems to work, tired hdmi, tried dvi, one needs to live with something especially if it was unnoticeable like the gamma shift.

thank you guys for the info and the support, now i got the monitor angled just right, the effect is now more unnoticeable, maybe 95% fixed, just needs a better angle, but the default stand it came with is total rubbish...