The Official ChromaPure thread - Page 137

Something I should have mentioned, but simply forgot, is that for reasons that escape my understanding I now find that I get MUCH better results when doing a Lumagen grayscale calibration when It is done from the bottom up (10%-100%), rather than from the top down (100%-10%). In recognition of this, we need to change the order in auto-cal as well. I already have this in beta, so it should be released in the next day or two.

The ability to control the Radiance and the DUO from inside CP is a great feature and much appreciated. The DUO will wear your hand out and who the heck wants to learn the Byzantine interface on the Lumagens any more than they absolutely have to.

Thanks Tom.

All very good stuff and much appreciated.

Don't have the AutoCal, but your Manual Mode always started at the Bottom. But, I've found, as soon as 100 is brought to spec, it throws all the others off, and they have to be re-done. Then every time 100 is brought back in line again, same again. It appears 100 affects all the others more than, any other reference point. (Forgot, sometimes 10 changes things as well.)

Always found that if I got Green in line from 100 to 10, then Blue, then Red, everything went quicker, and easier, but the Auto function seems to keep working with all 3, and doesn't seem as smooth a calibration.

If you calibrate the white balance gains in the display at 100% prior to doing anything with the Lumagen, then you should be able to start the Lumagen grayscale calibration from the bottom. Then 100% shouldn't actually need any work when you do get to it. However, you'd probably want to take a 100% reading first to get a reference point for the other levels.

1. Adjust 100% using the Display's own RGB grayscale controls.
2. Using the White Balance module, now adjust every other point using the Lumagen control within CP.

Note: I just found that the relevant variable is not top-to-bottom or bottom-to-top, but what control is used for 100%. The White Color control, which used to work wonderfully at 100%, no longer does. It can be used, but only if calibrating bottom-to-top, and even then you'll have to go back to 80 and 90% to readjust. On the other hand, using the 100% grayscale adjustment in the Lumagen works fine, does not have the interactive effects, and it doesn't matter whether you go top-to-bottom or bottom-to-top.

Finally, Lumagen recommends that you do NOT use the 100% grayscale control. I think because it can result in banding artifacts. This is why they recommend using the display's own control to adjust 100%. Once that is done the rest is a breeze.

FWIW, I am seeing none of these issues using the Duo. Of course, the Duo has other shortcomings, but for basic 10-pt grayscale, gamma, and 6-point gamut calibration it is hard to beat.

Final Note: Other than at 100%, where it may be necessary, you should not adjust green when doing grayscale. Stick to red and blue adjustments only. Green has too much of an effect on gamma.
Edited by TomHuffman - 3/21/13 at 6:56pm

Tried fine tuning the Lumagen tonight, but found the + or - .5 increments too great. Where can the settings be changed to + or - .1 ? In the lower values, + or - .5 shot the RGB all over and was hard to adjust correctly.

When you cintrol the lumagen from within chromapure with the new control toolbar, you can use clicks, which are .5 increments, or you can highlight the value and enter it manualy with whatever number you like, also meaning .1 increments. You can find a demo on this on the chromapure demo website.

Jeroen1000:

I found solution to resolve international settings for CP to work correctly for all reports (including Excel).
Leave Language as is (mine is Slovak)
Open regional settings and set following (I attached snapshot from my other PC for reference in english language for better understanding)

Decimal symbol set to "." (point)
List separator set to "," (comma)


Edited by prsut - 3/21/13 at 11:51pm

This is a great news....can't wait to see this.

Lets go Tom, I want to calibrate this weekend!

Does the new Color Checker module presume a certain gamma?

If so, what is it?

Is there an automated process that will programatically make and report all the measurements or do we make them one at a time as it would appear?
Edited by JimP - 3/22/13 at 8:31am

This issue is more for 8-point users than 125-point, which re calibrates grayscale at 4 points in any case. While you are waiting, why don't you try the new Lumagen control toolbar? I think that you'll find that you can do a calibration this way manually very fast (15-20 minutes). Use the toolbar with the White Balance module for grayscale, Color Management module for color, and the Gamma module for gamma. Check your work in the Post-Calibration Grayscale and Color Gamut modules.

Good question. Yes, it assumes a 2.2 gamma. Anytime you convert from RGB to xyY or vice-versa, you must have a gamma (or degamma) value.

Currently, you have to make them one at a time.

Is this a feature request? If so, be as specific as possible.

Would it be possible to use measured gamma when you determine/calculate the target within chromapure?

Yes, this is the correct procedure.

I think that Jeroen1000 wanted something in CP that would render this step unnecessary.

It would be possible I guess, but I don't think it would be desirable. What would be a better idea is perhaps a gamma selector that allowed other choices beyond 2.2.

That's right. You don't have to use the spinners. You can always click inside the box and type any manual change you like. This is useful for making unusually large or unusually small changes.

yes, ideally the same selection values for all modules (gamma, auto cal, color checker, etc)(including BT.1886).

This sounds awesome....I'll definitely give it a tryout!!

OK, I have uploaded a 2.4.1 beta at

http://www.chromapure.com/distribute/beta/chromapure.zip

This just addresses the issues discussed with auto-cal (visibility of controls and the 100% calibration).

1. Pre-calibrate 100% using the display's own RGB white balance controls and CP's White Balance module. This will just take a minute or two.
2. Set auto-cal to reset settings to default (this generally provides better results).

The only change to the auto-cal routine we made was to use the 100% grayscale control instead of the White Color control at 100% stimulus (if you pre-calibrate here neither would be used anyway) and to run the routine from bottom-to-top, rather than from top-to-bottom.

I ran two grayscale/gamma and 8-point calibrations on my Pioneer plasma (no 100% pre-calibration). The first is with the Pioneer set to Movie mode, so small adjustments were required. The second is using the Standard mode where large adjustments were required.

Here are the results, unedited.

CalibrationSummaryDetailed-Movie.pdf 283k .pdf file

CalibrationSummaryDetailed-Standard.pdf 306k .pdf file

The Movie mode calibration using a D3 took 6 minutes. The Standard Mode calibration took 9 minutes. Obviously, a 125-point calibration will take longer, in the 20-25 minute range.
Edited by TomHuffman - 3/22/13 at 2:05pm

Tom,   What about a display w/o a CMS, such as the SonyVW1000ES?    What pre-calibration is possible (or necessary)?

This isn't about the CMS. It is about the 100% grayscale point only. Use the Sony's own RGB grayscale controls and CP's White Balance module to calibrate white at 100% before running auto-cal.

An unrelated question I would appreciate help with:    when I try to print something from the Forum nowadays, the printing is very light, barely readable.   It didn't used to be this way.   Is there something I'm missing on a 'preference' or a print facility?

Good to see 0% readings added. This does however make AVSHD rather less convenient due to there being no 0 IRE pattern in the ChromaPure sub-section.
I wonder if alluringreality would consider authoring a new disc to accommodate this?

I tried a few times yesterday with the 2.4.0 but the results were bad and odd. Today I tried with 2.4.1 and followed the instructions, worked perfectly. Image looks great!


Because of my lack of experience I cannot say if the small windows are what made the difference, but to me it seems using them made my vt50eu a lot better. Clearer, brighter image.

Worth the wait!
Edited by Wouter73 - 3/22/13 at 3:00pm

Duplicate

Duplicate

small windows - 1% or 2% ?

Actually, it has nothing to do with window size. It was just changing the 100% calibration method and going from top-down to bottom-up. The 100% method change alone probably would have done the trick, but changing the order certainly didn't hurt.

Remember, until we release the full version of 2.4.1, all Lumagen 8-point calibrations must use 100% stimulus patterns.

Whatever the Lumagen uses. I haven't measured them. They are very small, I think smaller than they need to be. We use 5% small windows in the AccuPel and Duo.