Dual monitors, same model, connected to different vid card outputs, colors dont match

[dmantx]

I have 2 BenQ GL2460HM monitors connected to my MSI GTX 970 Gaming 4G card
Card has 1 hdmi, 1 displayport, and 2 DVI outs
all onboard settings on the monitors match
all pc settings in nvidia control panel match

monitor 1 - card hdmi to monitor hdmi with hdmi cable, vizio brand
monitor 2 - card DVI with DVI-hdmi converter to hdmi on monitor with hdmi cable, blue ridge brand

please see attached photo, the black on monitor 2 on right looks faded, less black...
I have used this image as reference - http://www.lagom.nl/lcd-test/black.php#blacktest.png
and on monitor 1 i dont see any individual boxes above bottom row, monitor 2 sees all of the individual boxes...

I have a few questions about this;

does the graphics card output different color/picture data to each port?

is the DVI-hdmi converter causing me to lose color/picture?

would it be any better using a displayport-hdmi cable for monitor 2?

would i have better luck matching color on both monitors is i used DVI ports with dvi-dvi cables?

 

[k1114]

In nvidia control panel, go to change res, on the bottom is says color output, make sure it's set to rgb and full.

 

[Eximo]

Well, monitors have to be calibrated to be perfectly frank. No two LCD panels will be 100% identical.

The connection type shouldn't matter, as it is all digital. You could try it, but don't expect different results.