Why have we changed over to a white target with a black kill zone, see'ing that our reticles on our scopes are black? It is particularly difficult to shoot at a black kill zone with a nato recticle.
the reason for this is one of, when the kill zone was white, after a couple of shoots especialy at 13mm and 20mm the colour was gone so now you have black KZ and black face plate this makes it more difficult to shoot than the other way around.
the only argument is that you can see where the other shooters missed! the thing is were did they aim? if there is wind they surely did not aim at the center of the KZ, so this does not help much either.
If you adjust the focus on your occular lens correctly (the lens at the back, where you adjust the clarity of your reticle), then it is no problem at all, seeing it clearly on a black background. The best way to do that, is to aim at a white wall, and then adjust the occular lens, untill the crosshair is crisp and clear, and as black as possible.
Just remember that you should always focus on the crosshair, and not the target, when shooting.