What I have found out is that if you adjust your User Interface file, you will be able to increase your gamma for H1Z1.
First go to your H1Z1 Folder and open the UserOptions.ini file location below (I am using notepad++ FYI):
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And then adjust Gamma as illustrated (What works for me is 1.00000):
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There is also a lot of other options that I haven't even started to try out but the gamma option works full screen also for me.
Let me know if you have any questions.
See you in there
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***Update***
For information on the rest of the options check out this link below
https://docs.google.com/spreadsheet/ccc ... ring#gid=0