[bcec]

I am trying to calibrate my Samsung hu8550 display using i1Display Pro.

I am seeing very different results if I calibrate HCFR vs ChromaPure. Attached are results of calibrating with HCFR and measuring with HCFR and ChromaPure. HCFR thinks everything is correct, but ChromaPure disagrees. Similar problem when I use ChromaPure to calibrate and then both to measure for comparing.

I selected the following display types:
HCFR: LCD White LED IPS (WLED AC LG Samsung)
ChromaPure: Samsung_LCD_LED

EDIT: Nevermind, I was using different dE calculations between the two apps. I am going to stick with HCFR. Any recommendations on how to get the gamma curve closer to BT1886?

 

[buzzard767]

Try not using any colorimeter offsets and see what you get.....

 

[LastButNotLeast]

Click on the little down arrow next to "Editable data." That will reveal a row labeled "Y target." Compare that to your Y. Increase or decrease R, G and B evenly to get the numbers (Y) close, then adjust R/G/B individually to get your dE back. Note that there is no Y target for 100%, but changes in 100% make a dramatic difference at that end of the curve.

Michael

 

[randal_r]

Click on the little down arrow next to "Editable data." That will reveal a row labeled "Y target." Compare that to your Y. Increase or decrease R, G and B evenly to get the numbers (Y) close, then adjust R/G/B individually to get your dE back. Note that there is no Y target for 100%, but changes in 100% make a dramatic difference at that end of the curve.

Michael

The "Y" value is set based on the screen luminance (such as adjusting the backlight of the display); also 0% is set.

My hat is off to you. This has been a pet peeve of mine for a while and many do not seem to relate how the "Y" to the Target "Y" can have an extreme overall effect. Many think that all you have to do is put the dot in the box or just match y to y and x to x.

 

[LastButNotLeast]

Thanks. But I think the biggest problem is that that entire row is hidden unless you know how to find it. Apparently, that isn't an easy thing to change (or zoyd would have done it several iterations ago). It's hard to hit a target unless you know what you're aiming for.

 

[randal_r]

Thanks. But I think the biggest problem is that that entire row is hidden unless you know how to find it. Apparently, that isn't an easy thing to change (or zoyd would have done it several iterations ago). It's hard to hit a target unless you know what you're aiming for.

I agree with you 100%. Just for the record I now only use CalMAN. In the past I have used HCFR (even built the probe). No matter which software one uses, the procedures and theories are the same.

In many standard Calman workflows it is almost impossible to find a screen that will show the x,yY and the Target x,y,Y on the same screen; especially with regards to grayscale adjustments. ChromaPure only shows the Y and Target Y together on the gamma adjusting screen. As for HCFR, you have stated the point and the solution very well. With regards to other software packages, I can not comment as I have never used them.

Your comment "It's hard to hit a target unless you know what you're aiming for", rings so true.

 

[TomHuffman]

ChromaPure only shows the Y and Target Y together on the gamma adjusting screen.

Y is luminance, which can be represented in a variety of ways. You are referring to one of those ways only--absolute luminance. This is raw numeric value (in fL or cd/m2). ChromaPure shows the target luminance in many modules, just not as an absolute numeric value. For example, the Color Gamut module contains a luminance error chart. The target luminance is zero error. The Color Management module contains a HSL-RGB-xyY error chart. Again, the target luminance is shown as zero error for the L, measured color, or Y value. The grayscale module shows the gamma value at each level, which is proxy for target luminance allowing you to compare measured luminance with desired luminance.

Numeric absolute luminance has very limited value (almost all color science equations rely on relative luminance--the absolute value is irrelevant). It is useful for knowing reference output and black level, both of which are used for calculating contrast ratio and setting the contrast control. That's about it.

 

[randal_r]

Y is luminance, which can be represented in a variety of ways. You are referring to one of those ways only--absolute luminance. This is raw numeric value (in fL or cd/m2). ChromaPure shows the target luminance in many modules, just not as an absolute numeric value. For example, the Color Gamut module contains a luminance error chart. The target luminance is zero error. The Color Management module contains a HSL-RGB-xyY error chart. Again, the target luminance is shown as zero error for the L, measured color, or Y value. The grayscale module shows the gamma value at each level, which is proxy for target luminance allowing you to compare measured luminance with desired luminance.

Numeric absolute luminance has very limited value (almost all color science equations rely on relative luminance--the absolute value is irrelevant). It is useful for knowing reference output and black level, both of which are used for calculating contrast ratio and setting the contrast control. That's about it.

You have given me much to think about. Thank you for the response.

 

[bcec]

Click on the little down arrow next to "Editable data." That will reveal a row labeled "Y target." Compare that to your Y. Increase or decrease R, G and B evenly to get the numbers (Y) close, then adjust R/G/B individually to get your dE back. Note that there is no Y target for 100%, but changes in 100% make a dramatic difference at that end of the curve.
Michael

Wow thanks a lot for that. I've wasted hours trying to do this blind.

Thanks. But I think the biggest problem is that that entire row is hidden unless you know how to find it. Apparently, that isn't an easy thing to change (or zoyd would have done it several iterations ago). It's hard to hit a target unless you know what you're aiming for.

What I was going to say. I would have never guessed that there was an additional row.

 

[LastButNotLeast]

Wow thanks a lot for that. I've wasted hours trying to do this blind.

What I was going to say. I would have never guessed that there was an additional row.

You're welcome. That's why we're here. I'm sure I did the same and found out the same way.

It's been suggested that zoyd add that to his sig. Maybe I'll put it in mine some day (since, obviously, there isn't enough there now ).

Glad it helped you. Now get to work!

Michael