Hi all, sorry i've been out all day, only just had chance to catch up on things.
I've since checked the screen on a fresh windows xp install to rule out color profile issues, and also on a friend's computer to rule out display card as the problem. They own a CRT, and like my old CRT, no such problems on checkemon.
I've just tried the 50 brightness 47 contrast, 72r 66g 75b trick, and also 50rgb settings, and it reduces the banding, but i think that's because it drops the contrast level by a similar degree.
I think i've ruled out every possibility except the dvi cable and the monitor itself. I don't know enough about DVI signalling to say if a bad dvi cable could cause this issue, tho i suspect a bad dvi cable is more likely to show digital errors such as pixels missing red green or blue data entirely.
I did a bit of research last night before bed, and some testing with different things. Here's a gradient image that shows the issue up nicely -
http://img527.imageshack.us/my.php?image=greengradgf4.png
With the right OSD settings, typically factory defaults, the horizontal gradient has no banding. But with any combination of OSD settings the vertical gradient banding will remain. If you download the image and rotate it 90 degrees, the gradient orientations switch and the previously banded gradient is fine, but the other one is now banded instead. The value for each pixel in the image is identical, only their orientation on the screen changed, which to me says this is not gamma or calibration related, but purely down to image processing performed by the screen.
You can further test this by moving the cursor around the image and noting the 'smear' effect on the bands directly below the cursor. Another interesting effect can be done in photoshop where you create a
hard edged large diameter brush (about 3 bands in width) and paint a solid circle over the banded gradient. Around the sides of the circle, the bands dissapear, as if the shape next to the gradient disrupts the banding effect. Just like the cursor effect, there is a also a column of smear on the bands directly below the circle too.
Slightly less empirical but visible to me is that the bands seem to be inverted bars of gradient, where in a gradient that goes top to bottom dark to light, each band is a smaller gradient of light to dark.
Personally i'm almost certain now that the problem is down to image processing performed by the screen. A little bit of research on 'genesis banding' shows the issues when the dell 2405 was replaced by the 2407 which used the genesis chip. Firmware updates were done to remove horizontal banding (caused by faroudja video processing being enabled when the monitor was in 'desktop' mode), but still left noticeable vertical banding. I can't find the page i was looking at last night but it was shown that entering the service menu and disabling ACC fixed the gradient problem. The hazro uses a Genesis chip and depending on the chip used, may have either ACC and/or faroudja enabled -
http://www.gnss.com/prod_lcd_mon.phtml
Unless there's a way to enter a service menu on the hazro's, there's no real way to find out. Personally i think it's more likely to be ACC than faroudja related.
I actually came across this problem by accident, testing my hazro in 3dsmax, i happened to use a simple gradient shader. Aside from these synthetic tests, i haven't seen the banding cause an issue in any photographs or movies, however the banding is revealed in one game i play with a simple grey-black gradient background on it's toolbar.
myshkinbob: Would like to ask you a question as I see you too have owned the digimate 24". I sold mine after a week because it's brightness burned out my eyes.
Now I read about possible trouble with the hz24wi brightness. Is the Hazro equally bright ?
The hazro is quite bright by default, although it doesn't feel as harsh on the eyes as the digimate 24". I'd say it's still too bright though, just not like staring into the sun like the digimate was. The image quality is also vastly superior, with excellent dark details and colours are much more natural, especially skintones.
It's nothing major but just an annoyance especially if you calibrate at regular intervals.
