graphic display card have better profile?

[ato]

my PC installed 7950GT and quadro1300

i tried many time the result are same,quadro1300 gamma curve always better than geforce7950

they both connect DVI port and use hardware calibration,anyone have this experience??



quadro1300



geforce7950

[Jonathan Wienke]

The differences between the plots are negligible; probably not statistically significant.

Also, with DVI, the video card really plays no role in profiling, since communication between the card and monitor is all digital. The monitor is the only significant part. With VGA, you're profiling not only the analog response of the monitor to input signal voltages, but the analog response of the video card to various input values going into the DAC chip and coming out the jack on the back of the card. A VGA profile is only good for a specific video card - monitor pair, while a DVI profile is good for the monitor, no matter what card it is connected to.

[CEE]

The differences between the plots are negligible; probably not statistically significant.

Also, with DVI, the video card really plays no role in profiling, since communication between the card and monitor is all digital. The monitor is the only significant part. With VGA, you're profiling not only the analog response of the monitor to input signal voltages, but the analog response of the video card to various input values going into the DAC chip and coming out the jack on the back of the card. A VGA profile is only good for a specific video card - monitor pair, while a DVI profile is good for the monitor, no matter what card it is connected to.
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Jonathan, I am so happy to find your post about the role video cards play in the business of profiling. I have a 22" Viewsonic being fed by an NVidia 7900 GS DVI output (I use an Eye one Display 2 for creating the profile).

I have asked NVidia for information about how the card will affect the use of a monitor profile and also the card implements the LUT created by the Eye One and can't seem to get an answer from them. What I understand from you is that the DVI output of the card has no effect and the profile created is implemented without being changed by the video card?

Kindest regards, Carl

[jackbingham]

"is that the DVI output of the card has no effect and the profile created is implemented without being changed by the video card?"

This is only true if the monitor and calibration software are ddc. if there is no hardware communication with the monitor, all adjustments will be made in the card. There is no reason for the video lut to be a perfectly straight line with all three colors. Nor is there anything wrong if the three curves vary widely. The video luts are there to make adjustments to make the monitor more accurate. if the monitor happens to adhere to your target parameters, say d65 and max luminance then the curves will show little change. On the other hand if you targt d50 and 50% of the moniotor's max luminance the curves will look radically different. There is no reason to expect two cards to show the same luts just because they happen to be driving the same monitor.

[jackbingham]

"A VGA profile is only good for a specific video card - monitor pair, while a DVI profile is good for the monitor, no matter what card it is connected to."

I guess i would disagree with this also. if the display is not ddc all the changes will be made in the video card lut.

[CEE]

"A VGA profile is only good for a specific video card - monitor pair, while a DVI profile is good for the monitor, no matter what card it is connected to."

I guess i would disagree with this also. if the display is not ddc all the changes will be made in the video card lut.
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A couple of additional questions please.

1. How do I determine if my monitor is DDC?

2. When I create a monitor profile with the GretagMacbeth Eye One Display 2, nothing is mentioned about wether or not the profile is VGA or DVI. The Nvidia card has two DVI outputs one of which is connected to my 22" Viewsonic monitor. From what I read, the monitor profile created by the colorimeter is specific to the monitor on which it was created. Nothing is mentioned in the instructions for the colorimeter about DDC or DVI. Is this not the case?

3. The Eye One also allows for the creation of either a LUT or a matrix profile, Which is best.

By the way, I am not new to photography but I am relatively new to the digital world. I shoot with a prosumer grade digital camera in sRGB (that's all it can do) and process my files in the sRGB workspace as well. I had this work flow recommended because most all of the photolabs that process digital prints do so in the sRGB work space. Only the high-end labs and CMYK processors use 1998 Adobe RGB. What is your opinion?

Carl

[Jonathan Wienke]

"A VGA profile is only good for a specific video card - monitor pair, while a DVI profile is good for the monitor, no matter what card it is connected to."

I guess i would disagree with this also. if the display is not ddc all the changes will be made in the video card lut.

No two video cards output the exact same analog output voltage for any given RGB value goint into the DAC, so if you swap out the video card, the monitor profile will be invalidated to some extent. It may not be a huge deal if you replace the catd with the same brand and lot number of DAC chips, but if you switch brands of video card, the difference can be quite dramatic.

If the communication between video card and monitor is digital, then moving the monitor to a different, but identically configured, video card, will make no change in the colors output by the monitor. The same digital RGB values sent to the monitor will result in the same colors being displayed by the monitor. If the communication is analog, then changing either the video card or the monitor will alter the colors output by the monitor from any given RGB value.

[Jonathan Wienke]

Nothing is mentioned in the instructions for the colorimeter about DDC or DVI. Is this not the case?

The profile doesn't know or care. All a profile describes is what color is output by a monitor when a given RGB value is sent to the video card. The connection between the video card and monitor doesn't really matter unless you're swapping a monitor around among several computers, something you should avoid if possible. Don't swap, and don't worry.

3. The Eye One also allows for the creation of either a LUT or a matrix profile, Which is best.

LUT profiles are larger, but more accurate.

I shoot with a prosumer grade digital camera in sRGB (that's all it can do) and process my files in the sRGB workspace as well. I had this work flow recommended because most all of the photolabs that process digital prints do so in the sRGB work space. Only the high-end labs and CMYK processors use 1998 Adobe RGB. What is your opinion?

Shoot RAW, use ProPhoto as your output space in your RAW converter, and then convert to the needed RGB space yourself as the final step in the editing process. If you do it, you can control how highly saturated colors that your camera sensor can see get shoehorned into smaller color spaces like sRGB. If you shoot JPEG, you give up color gamut, dynamic range, and the editing flexibility of 16-bit files, and add compression artifacts to your image as well. THink of JPEG as developing and printing your film at the corner drug store ant throwing away the negatives, while RAW images are like undeveloped negatives you can process over and over again however you like.

[eronald]

LUT profiles are larger, but more accurate.
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In theory, Jonathan, in theory. The Devil and Photoshop are in the details ...Do a banding test in CS1 and see what I mean ...

Edmund

[jackbingham]

"If the communication is analog, then changing either the video card or the monitor will alter the colors output by the monitor from any given RGB value."

Regardless of what input you use, dvi or analog there will be a video lut saved unless the monitor is a fairly complete ddc deal. If you are saying the cards are so similar that the same lut in multiple cards will yield the same result, I have not tested that but I suspect manufacturing variations makes that unlikely. If you are talking about ignoring the lut entirely this would be completely wrong. Monitor profiling involves two very different steps. Calibration which can take place in the hardware of the monitor and the card or just the card. profiling is built on top of that calibration so the video lut in the card plays a critical role here.

[jackbingham]

. Nothing is mentioned in the instructions for the colorimeter about DDC or DVI. Is this not the case?

Many monitors are now ddc. Of course there are now several flavors of ddc with different capabilities. Check your user manual or go to the web and research this monitor at the manufacturers site. If it is ddc compliant and if your card and software are you can build a monitor lut based profile which will be more accurate and simpler to build.