[argyllcms] Re: CRT controls

  • From: "Rhys Evans" <rhys.evans@xxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Thu, 6 Mar 2008 11:53:47 +1300

On 06/03/2008, Graeme Gill <graeme@xxxxxxxxxxxxx> wrote:
> Roger Breton wrote:
>  > You need to set yourself some numerical targets. Like 90 to 100 cd/m2 for
>  > the white and 0.30 to 1.00 cd/m2 for the black.
> The target values for black are the 1% values.

Yeah, that's what I generally aim for, is there a setting to specify
black in cd/m^2 or percentage though? There's -b for brightness so if
that's specified it should just be 1% of that yeah? So going below
that level would increase the contrast of the display but you'd make
the choice for yourself rather than the software setting it as a

>  >>On a related note, if I repeat the black level portion of dispcal it
>  >>wants me to go lower with each iteration despite meeting it's target
>  >>each time. Is this just trying to get to a level of 0 limited by the
>  >>default -k factor? Is there a level I should be aiming for short of
>  >>pure black?
> I'm not sure about this, as I haven't observer it myself. I would
>  expect some interaction between brightness and contrast (offset and gain)
>  controls. Does the black level vary much ? Is the change getting
>  less each time around ?

It's generally not much, but always downwards. I haven't done heaps of
iterations though to see if it finds a level it likes, I just do 2 or
3 runs and move on to the next steps in dispcal.

>  The pragmatic thing is simply to stop after one or two iterations,
>  probably after the black adjustment, since it is likely to be more
>  critical.
>  Graeme Gill.

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