Black crush on 8740w with Firepro/Dreamcolor display

I've had my 8740w for a little while now, and I love it, but one little issue keeps nagging me: The Dreamcolor display severely crushes blacks, and it does so far worse than any of the crappy 6-bit TN panels I own. The problem could possibly be the Firepro on my build, but I'm pretty sure it's the display. (I recall reading a review of a desktop Dreamcolor monitor where the reviewer briefly mentioned an issue like this.)



I've read about uneven gradient ramps in the owners' lounges, but this specific issue is a little bit more than typical 8-bit imperfections. For those of you with Dreamcolor displays, check out the gradient ramp on . Save it, open it up in an image editor, and zoom in. Using a color picker, you will notice that all 256 shades of gray are represented in 8-bit color, with three columns for each.



Zoom in and look at the gradient from right to left. As you approach black, you will notice that the monitor displays the exact same brightness for increasingly wide ranges of values. I've verified that the same issue exists in both Windows 7 and Linux, but I'll give an example from Ubuntu 10.10 with proprietary ATI drivers and default brightness/contrast/gamma in the drivers (since it's convenient for me ATM):

• RGB 0-10 is pure black, with no differentiation
• RGB 11-14 is the next step up, which is significantly lighter.
• RGB 15-18 is the next step up, which is significantly lighter again.
• After that, brightness gets more fine-grained, until each consecutive RGB value is slightly brighter than the last.

Adjusting brightness/contrast/gamma in the graphics options can redistribute the brightness levels across RGB values, but there will always be a sizable brightness jump between the darkest, second darkest, and third darkest shades, and they still attempt to cover a large range of RGB values. It's almost as if the display itself is only capable of displaying a very small number of dark colors (which I hope is untrue). The only way to get decent detail in the darks is to increase driver brightness and decrease driver contrast until the image is washed out. Reducing gamma helps correct for that, but then much of the detail gain in darks is lost.



I understand that you can't expect a perfect gradient ramp on an 8-bit display, or a 10-bit display using 8-bit mode/images. There will generally be some duplicate brightness values across different RGB values, and that's perfectly normal. However, even my worst 6-bit TN display has a much better distribution of brightness levels near black, leading me to believe the Dreamcolor has a flaw somewhere in its implementation. Perhaps the lookup tables are messed up, or dithering isn't being performed when it really should be.



So, are the rest of you guys experiencing the same issue? If we're all affected, as I suspect we are, we might be able to ask HP about a possible firmware fix.

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