Originally Posted by thrang
I just got a Mini3D today (thanks Mark) and overall find it to be a great unit, better than the Duo. I'm using with the Chromapure (auto cal), and it generally does a very good job. But I am confused on how to adjust saturation, hue and lightness with the Mini - I understand you are using a different, and I suppose, more accurate model, but when manually tweaking CMS, if my Blue, Cyan and Magenta are showing a little over or under stauration, and some hue or lightness offset in Chromapure, how do I go about dusting this up?
Is there some more detailed documentation on the CMS operation, as to how things work, and what sequenced steps should be taken if I wanted to do a complete manual attempt?
I'm 98% there...
I understand Chromapure will come out with an upgrade early next year that will allow manual control of the Lumagen from within there software, so I presume manual tweaks will be easier as it will manage the translation of adjusting HSL into your model, but until then, some additional guidance would be appreciated.
Originally Posted by lovingdvd
Like Thrang, I too would greatly appreciate some tips on how to work with the color space used by the Radiance in their CMS. I am very familiar with how to determine the proper xyY targets for each of the primaries and secondaries.
However I'm not sure how when looking at a measured result how to go about adjusting the Radiance CMS controls to increase or decrease each of the x, y, and Y values to move it where I want it.
For example let's say I am trying to get Red to 0.640 (x), 0.330 (y), 21.26 (Y). Now assume I take my Red measurement and I get 0.635, 0.320, 20.26. Which CMS controls would I use and in which direction would I move them to make the needed adjustment. An explanation of that would explain what I and I believe Thrang (and others!) need to know. Thanks.
It's actually quite easy once you've got your head around it
The principle is that you affect directly the RGB values for each color, adding or substracting the right channel(s) to get where you want to be.
So if luminance is too low for one color, you raise all RGB values in the same proportion (see below possible restriction).
If luminance is too high, you lower them in the same proportion.
For saturation and hue (slightly trickier), I suggest you read the following thread in the Radiance forum, it's pretty clear.http://www.convergent-av.co.uk/forum...9d24#msg_15153
, especially Gordon's post at the bottom of the page (and following).
I, like many others, prefer to use the matrix mode rather than the single color mode (except when adjusting gamut white, see below).
The most important thing when adjusting gamut is that if your luminance is too low for some colors to be adjusted, you need to lower gamut white, which will raise the relative luminance of all colors until no color has too low a luminance, as you can't raise luminance in the Radiance (unless you have already lowered it of course), only lower it.
See this thread http://www.convergent-av.co.uk/forum...hite#msg_17713
for more info on the gamut white adjustment.
Also always adjust RGB white balance at 100IRE using the gain controls in the display - when possible - to make sure you have a correct starting point for either a manual or autocal.
Workflow goes like this:
1) Set gains at 100IRE (using the display's controls) to get white right at that level.
2) Measure all colors
[step added following edit, see below] 2a) make sure you select a color profile in the display where all colors sit outside the rec-709 triangle. Undersaturation is NOT correctable.
3) If luminance is too low for any color, adjust gamut white (lower its luminance, ie lower RGB for gamut white in the same proportion) until no color has a low luminance, otherwise you won't be able to adjust it/them
4) Adjust each color (following method and Gordon's advice in linked thread), giving priority to luminance for primaries and hue for secondaries if you have to make compromises
I'm sure Jim and others will help if you're still stuck (or correct me if I'm wrong
EDIT: Thrang, be aware that no external VP or internal CMS can correct UNDERSATURATION, ie it's not possible to invent colors that the display is not able to reproduce. When you measure your gamut before correction, if it shows undersaturation for any color, no calibration, auto or manual, will be able to correct it. You need to select a color profile in the display where ALL the colors are OUTSIDE the rec-709 triangle, or you won't be able to correct them. With the latest JVCs, it often means selecting profile off and using the service menu to correct the gains at 100IRE, but that's only possible if you have enough range in the controls (both in the PJ and the Radiance) to correct greyscale and gamut, as profile off gives a very green/blue greyscale and a very oversaturated gamut. Most of the time, you'll get bettter results living with the small undersaturation of a profile which is slightly undersaturated (yours seems absolutely fine!). Sometimes, trying to correct minor errors can actually produce WORSE results visually (adding posterization or clipping) even if your graphs and charts look nicer... All your dEs are below 1, which is a great result. It's unlikely any correction could improve this visually, provided your meter is accurate.
EDIT2: be careful when measuring blue, it's a notoriously difficult color to measure for most non pro spectros, especially if you're measuring off a large screen without zooming your patterns down, or if your lamp is getting old. If a DIY meter (even an i1pro) tells you it's undersaturated, it doesn't necessarily mean it actually is...