Dreamcolor questions again

[Miguel "Macgregor" De Olaso]

Hi all, just before i take the effort of taking my screen to HP tech support, i´d like to ask you what luminance/brightness are your dreamcolor screens giving you with the factory default rec709 color space. I just updated the firmware to the latest version and the screen drops to a superlow level of 48cd/m2 while the gamma curve seems all messed up (black level has increased so much that the darkest grey possible (1,1,1) appears very very bright).

Thanks

 

[silvio bonomi]

Confirm value of 48 for REC 709 in factory reset mode (but naturally is possible to increase value to desire...for me 120. Gamma 2.2 ok.D65. The problem now is with Snow Leopard. HP probe profiler (EYE-ONE...) with HP APS calibration software 1.0.2 for Mac SO. NOW NOT RECOGNIZED and so NOT WORK!!!

silvio bonomi

 

[Maz Mawlawi]

Our Dreamcolors work perfectly for us. Default REC709 default to the following

Red-X 0.640 Red-y 0.330
Green-x 0.300 Green-y 0.600
Blue-x 0.150 Blue-y 0.060
White-x 0.313 White-y 0.329
Gama 2.400
Color Corrdinate - u' v'

Brithness 120 cd/m2
White point 6500K

Hope this helps

 

[silvio bonomi]

Our Dreamcolors work perfectly for us. Default REC709 default to the following

Red-X 0.640 Red-y 0.330
Green-x 0.300 Green-y 0.600
Blue-x 0.150 Blue-y 0.060
White-x 0.313 White-y 0.329
Gama 2.400
Color Corrdinate - u' v'

Brithness 120 cd/m2
White point 6500K

Hope this helps

Hi

Gamma at 2.4 in preset mode is a wrong value ( see instruction manual...) and is not possible to change gamma value. Infact in MAIN MENU/ COLOR SPACE/ PRIMARIES and GAMMA INFORMATION the control (is locked... ) as WHITEPOINT-COLORTEMP.
Only LUMINANCE-BRIGHTNESS value is modificable (...mine at factory preset was at 48...in 709)
This is a problem from factory presets charged at HP !!

The first Dreamcolor that I have has this issue (gamma at 2.4 in preset mode 709 no possibility to modify.... ) Call at Hp support that send me another Dreamcolor for (fix) this problem. Hp send me another: now (this) with right gamma value (gamma 2.2 in 709).

comments ?

silvio bonomi

 

[Miguel "Macgregor" De Olaso]

So i called HP tech support, explained the problem and they sent me a new screen, just 10 minutes ago. I´m going to test it but so far this looks much better. Good!!!!

 

[Miguel "Macgregor" De Olaso]

Hi

Gamma at 2.4 in preset mode is a wrong value ( see instruction manual...) and is not possible to change gamma value. Infact in MAIN MENU/ COLOR SPACE/ PRIMARIES and GAMMA INFORMATION the control (is locked... ) as WHITEPOINT-COLORTEMP.
Only LUMINANCE-BRIGHTNESS value is modificable (...mine at factory preset was at 48...in 709)
This is a problem from factory presets charged at HP !!

The first Dreamcolor that I have has this issue (gamma at 2.4 in preset mode 709 no possibility to modify.... ) Call at Hp support that send me another Dreamcolor for (fix) this problem. Hp send me another: now (this) with right gamma value (gamma 2.2 in 709).

comments ?

silvio bonomi

Uhmm, i also have gamma 2.4 as factory default rec709...

 

[Kaku Ito]

I heard once before that TVLogic technician mentioned that LED backlighted LCD would match gamma to CRT at 2.4.

 

[Miguel "Macgregor" De Olaso]

Greg Staten worte this in March:

Regarding the 2.2 gamma. Certainly that's the recommended gamma for Windows XP, but there's no reason you can't use another if you prefer. The key is to make sure you match what your target is. For example, after the initial release we tweaked the factory calibration for Rec.709 to raise the gamma slightly from the standard 2.2. The reason we did this is that we placed the monitor side by side with Sony BVM tube monitors and worked to match the actual response of the monitor. That resulted in a slightly higher gamma than 2.2.

-greg

So far what i´ve tested on the new screen looks perfect, definately my old screen had some kind of trouble even after firmware update.

 

[Michele Gavazzeni]

good to know!!!!

 

[Sean Kapleton]

dreamcolor headache

dreamcolor headache

Hello

I was hoping to find a fellow Dreamcolor user to help me make sense of this issue. I was trying to change the Gamma which is set to rec. 709, 6500, etc just needed to have access to changing to 2.2 from 2.4.

I had a professional calibrator come in and probe it to match my panny plasma as well - set it right to rec.709 but I could not seem to figure out how to change the Gamma which seems to be an important value to be able to adjust no?! I updated the firmware to the latest version but that did not help - unable to change from 2.4 to anything else - I am sending a 10 bit signal via DisplayPort from an HDLINK3D & Extreme 3D video card.

I am on a mac system so i had to lug over a friends pc tower just to be able to update the firmware...i did not download or use any of the other tools on hp's website, and no i do not use a probe because i had been doing it by eye for a few months with the intention of having it professionally probed - now i have a calibration expert coming to me to probe both the dreamcolor and my plasma to match rec. 709 as close as possible.

It seems that maybe the probe is specific to the Dreamcolor because there is a physical difference between it and other xrite probes (some filtration) -that you needed to use that software and probe alongside a non-contact probe in order to get at all the controls. I wonder if this is true? Its so unfortunate that HP doesn ot offer any good support for this product!!! Where is the US engineer / lab dept. that knows about this monitor?!

After having it professional calibrated by a pro using a 20k piece of equipment - along with my plasma some small adjustments were made to my Dreamcolor to get it as close to rec.709 as possible - here are my settings now:

rec.709 color space
6800K not 6500 (apparently was a little too red so he adjusted that to get it closer?)
120 brightness
black level 128

One thing we do notice now however is that the grey pluge coming from fcp color bars is VERY noticeable on the plasma while on the LCD Dreamcolor it is really barely visible - I was told by the calibrator that it is ok and that he probed both to be rec. 709 as close as possible.

fingers crossed that we invested wisely in the gear and the right calibration expert.

 

[stu aull]

Hi Sean-
Just found this thread, having purchased a used Dreamcolor this week. Am now trying to get my head around all the specs and requirements. Yoik!
Sean I have the Extreme 3D Blackmagic card too and have been told by Blackmagic that the 3D card's output will NOT trigger the Dream's Display port to show rec.709 because the 3D card does not generate the necessary Digital RGB signal. So I assume the HDLink 3D is routed between the Dream and the 3D Extreme to generate this?

I was advised by BlackMagic tech to use the HDLink as you have. So it was successful then? (or at least sort of?) would love to get more info on this, either here or thru PMs

regards
Stu Aull
Alaska

 

[M Most]

Hi

Gamma at 2.4 in preset mode is a wrong value ( see instruction manual...) and is not possible to change gamma value.

I think you might be misinterpreting what HP's literature is saying. The literature is written with the assumption that you're driving the Dreamcolor as a directly connected monitor to the computer's video card, and controlling the display parameters via a ColorSync profile in the case of a Mac, or some other color management system (Adobe, perhaps) in the case of a PC. What they're talking about is basically a warning about using the Mac's native gamma when trying to display as Rec709 on a Dreamcolor with that kind of connection. If, however, the Dreamcolor is being fed via an SDI video output, converted through an HDLink or an Aja HI5-3G or similar, the profile that is used is the internally stored profile, which has hopefully been updated by using the Advanced Profiling Solution. The gamma in that profile is 2.4 because that is what it should be based on the monitor's native characteristics. The image being displayed in that case has not been modified by the computer's color management system, it is standard Rec709 video output from a card designed to supply that (Blackmagic Decklink series, AJA Kona series, etc.).

Using the Advanced Profiling Solution and the standard Rec709 parameters almost always yields an effectively perfect Rec709 display unless there's either something wrong with the monitor, or the probe is not being used correctly, or the monitor has aged and cannot reach the preferred values. If anything, it's likely that the Dreamcolor, set up properly using the probe, is more accurate to the Rec709 standard than your plasma, regardless of how meticulously it's been calibrated. This is also true of other well designed LCD displays, such as the Flanders Scientific monitors. That hasn't stopped most major post facilities from using the plasmas, but their reasons for that decision are primarily rooted in the larger available sizes, the lack of off-axis falloff in the image (allowing clients to view accurately from different points in the room), and the solid blacks (which resemble CRT blacks).