Argyle error

[Steve Smith]

Hi Florian

I have attached a compressed archive and a gamut image showing a better example of the Argyle error(s) we discussed a little while ago.

I hope you can pass it along to the creator for review.

Thanks.

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[Florian Höch]

Is this with Argyll 1.9.2 or the 1.9.4 2017-02 beta that I posted? Make sure any TV “CMS” controls (hue/saturation/6-axis etc) are untouched (in default state) as these can introduce artifacts that cannot be calibrated away using a 3D LUT.

[Steve Smith]

I was using the current 1.9.2 version because I was getting good results…(For a while anyway.)

I re-ran the measurement data with the older Argyll 1.8.3 as you suggested and the artifacts disappeared.

I wasn’t making a 3DLUT,  just making a straight color profile using ‘Linear’.

I used CalMAN to do a 10 point internal TV calibration and a RGB CMS adjustment.

CMS and 2 pt, 10pt hardware adjustments can cause problems? Isn’t it better to start a calibration from a ‘closer to target’ position?

Does what you say only apply to 3DLUTs?

[Steve Smith]

Attached is a gamut image using the same measurement data as above to create a profile but this time using Argyll 1.8.3

So if version 1.8.3 works, does this mean the problem is with Argyll, or do you think that my CMS controlls are still somehow involved?

I varified this profile to an average de of .24 for grayscale, and .36 de for the color using the XXXL chart.

• This reply was modified 7 years, 1 month ago by Steve Smith.
• This reply was modified 7 years, 1 month ago by Steve Smith.

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[Florian Höch]

CMS and 2 pt, 10pt hardware adjustments can cause problems?

2 pt / 10 pt are usually ok, especially if only adjusting white. Reducing saturation (to prevent RGB channel clipping) may also be ok, but anything else is probably better left alone.

Isn’t it better to start a calibration from a ‘closer to target’ position?

Depending on how the TV controls are implemented and how they are adjusted, they may have adverse effects on the display response.

Does what you say only apply to 3DLUTs?

It naturally also applies to all measurements.

[Florian Höch]

So if version 1.8.3 works, does this mean the problem is with Argyll, or do you think that my CMS controlls are still somehow involved?

Possibly. As I understand it, one of the reasons this problem shows up with 1.9.2 is that changes were made in 1.9.2 that increase accuracy. In some corner cases like yours, these changes seem to have the side effect of not smoothing over display faults as well as 1.8.3 did, which then shows up as banding/artifacting. Nothing wrong with staying on 1.8.3 for the time being until the next Argyll release is ready if it’s not the display’s fault.

[Steve Smith]

Thanks…Ya, I’m not sure but it seems to happen when the ‘brightness’ on the tv is set a little too low. (Or maybe it’s when the ‘contrast’ is set a little too high) Lol… Those are the only changes I’ve experimented with when it happens.

…Ok, maybe slight adjustments to the cms did it, lol (Only a click or two here and there to get the gamut to line up.)

Do you think that re-running the measurement data in the current Argyll might turn up different results, or will it always be the same?

• This reply was modified 7 years, 1 month ago by Steve Smith.

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