CHROMiX

Native White Point

Hi,
I have calibrated my laptop screen with my lately aquired Monaco optix device.
Since I have no contrast setting on my computer, I choose ‘native white point’ for the white balance setting. I have noticed however, while performing several readings, that the whitepoint changes slightly, let’s say from 5226K to 5269K, everytime a bit different. Isn’t the native whitepoint a fixed value from the computer hardware?
If not, what is it calculated from?
Thanks for any hints,

Sidney

At 3:14 PM -0700 5/4/05, Carioca wrote:

Hi,
I have calibrated my laptop screen with my lately aquired Monaco optix device.
Since I have no contrast setting on my computer, I choose ‘native white point’ for the white balance setting. I have noticed however, while performing several readings, that the whitepoint changes slightly, let’s say from 5226K to 5269K, everytime a bit different. Isn’t the native whitepoint a fixed value from the computer hardware?
If not, what is it calculated from?
Thanks for any hints,

The white point is fixed (it’s a product of the backlights and the backing material in the display). The variation you are seeing is not too bad and is probably due to ambient lighting or changes in the voltage to to lamps or something. They say that you can’t see changes in K of 50 or less so you are still in an OK range.

It is measured right off the screen. It is also typically the best choice for flat-panel displays…

Regards,

Steve


o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX


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At 3:14 PM -0700 5/4/05, Carioca wrote:

Hi,
I have calibrated my laptop screen with my lately aquired Monaco optix device.
Since I have no contrast setting on my computer, I choose ‘native white point’ for the white balance setting. I have noticed however, while performing several readings, that the whitepoint changes slightly, let’s say from 5226K to 5269K, everytime a bit different. Isn’t the native whitepoint a fixed value from the computer hardware?

it should be, yes

If not, what is it calculated from?

it is quite possible that you are seeing measurement variation and not an actual change in white point… in fact I suspect it.

apparently you cannot see white point shifts less than 50K so I think you are in that range…

do you see any difference in the behavior of the laptop white point after calibration?

Regards,

Steve


o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX


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I’ve just had a similar problem. I used an Optix XR to calibrate my Apple Cinema Display twice, using native white point. The first time, the white point came out to around 7600, the second time it came out to about 6700.

When I switch between the two profiles, I don’t see much of a difference, though.

Thanks

It’s not clear from these posts whether time is being allowed for the monitors to stabilise before profiling.

I know CRTs need a long time (after first switching on) to stabilise - at least an hour, some need more - but for LCDs I don’t know what the typical stabilisation time is.

Steve, what sort of times are needed for LCD stabilisation?

I think this might be relevant.

HTH

Alan

At 11:16 AM -0700 7/31/05, alanrew wrote:

It’s not clear from these posts whether time is being allowed for the monitors to stabilise before profiling.

I know CRTs need a long time (after first switching on) to stabilise - at least an hour, some need more - but for LCDs I don’t know what the typical stabilisation time is.

Steve, what sort of times are needed for LCD stabilisation?

Unfortunately I don’t have a good answer for this one. I suppose the thing to do is fire one up and then continually measure the white point over time to see when it stabilizes… haven’t had the time for that yet…

We are listening to the vendors here and suggesting 30 minutes for LCD’s but I don’t have hard numbers so it’s tough to know for sure.

Regards,

Steve


o Steve Upton CHROMiX www.chromix.com
o (hueman) 866.CHROMiX


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