Datacolor User to User Support Group.

A few additions:

- Ambient lighting:

The ambient lighting in a 5m x 5m room consists of one 60W light bulb,
one fluorescent tube and one "warm tone" fluorescent tube. Together.
So, it's a mess, I know. This is not a lab. I can choose either
incandescent or fluorescent, though. I don't know about light levels,
but it's generally dim (and warm).

- Calibration method:

I adjust the RGB sliders on my LCD and CRT until Spyder3Pro says the
RGB levels are close enough. Then I let Spyder to profile the screens.

I forgot to mention that my CRT has both color temp and RGB sliders. I
use the sliders for calibration. Kelvins I only use in software to set
targets.


ps. I know that "everything is wrong": lcd+crt, old hardware, only one
graphics card (and consumer 3D card) and bad lighting and so on, but
still I try to get at least some improvement, with ~zero budget. In
the worst case, this just becomes a learning experience.

--- In colorvision_group@yahoogroups.com, "str_online"
<str_online@...> wrote:
>
> This seems to be more complicated than I first thought.
> 
> First, I will state my aims, and then ask a few questions.
> 
> I take digital photographs. I convert these to jpegs and distribute
> them for viewing on cheap consumer grade LCD screens at home. No
> printing. The ambient lighting is unknown, but usually dim, and LCDs
> are bright. I hope that if I adjust some tone visually to neutral
> grey, then it also looks neutral grey on the recipients LCD, given
> that it is reasonably grey-balanced at similar color temp that mine.
> 
> I have two screens because I want to keep editors open in one and
> music player, email etc in the other. I only work with images on one
> screen at a time.
> 
> ------------
> So... back to questions...
> 
> I initially calibrated both my CRT and my LCD to 2.2 gamma, 6500K. The
> OSD on the CRT allows me to set a color temp 6000K, 6500K, 7000K (and
> up). The LCD OSD has RGB sliders.
> 
> A few tries:
> 
>    Cal target Monitor OSD
> CRT 2.2 6500K RGB=56,51,46%
> LCD 2.2 6500K RGB=43,43,50% bad lcd-crt match
> LCD 2.2 5800K RGB=56,51,46% better lcd-crt match
> LCD 2.2 5500K RGB=60+,50,40-% I can't even get a neutral white here
> 
> - So I guess I should use 5800K for the LCD then? Maybe also try with
> 6000K for the CRT?
> 
> - Should I use 5800K or native fpr the LCD, by the way?
> 
> - Does this CRT-LCD matching have some adverse effects? Or should I
> just accept that the image looks different on two screens? That there
> cannot be something that's neutral grey on both screens at the same
> time? References, howtos, other litterature?
> 
> 
> --- In colorvision_group@yahoogroups.com, Cdtobie <CDTobie@> wrote:
> >
> > Several possibilities. First: you simply cannot harness a racehorse  
> > and a donkey together and get a working team. A CRT is a much  
> > different animal from an LCD, and it's just not reasonable to try to  
> > pair them for precision work.
> > 
> > Next: the fact that both displays show a change in SpyderProof does  
> > not actually guarantee that both have unique calibration data being  
> > loaded to them, and both are using unique profiles (seperate
items, by  
> > the way). The calibration could be great as you do each screen, but  
> > they may be overwriting one another if the card can't manage unique  
> > calibration data. Try adding another card.
> > 
> > Third: you don't note what process you are using to calibrate, or
what  
> > target values are involved. If you are at an inappropriate luminance  
> > or inappropriate whitepoint for your lighting level, then the two  
> > displays may be affected differently by this, being different
types of  
> > displays.
> > 
> > Whatever the cause, given the configuration you are trying to match,  
> > you may find it necessary to calibrate to two different
whitepoints to  
> > get the effect you want.
> > 
> > C. D. Tobie
> > WW Product Technology Mngr.
> > Digital Imaging & Home Theater
> > DataColor.com
> > CDTobie@
> > 
> > On Jan 19, 2009, at 9:00 AM, "str_online" <str_online@> wrote:
> > 
> > > I have attached two monitors to one dual-head graphics card on
Vista.
> > > Vista recognizes them both as "Generic Non-PnP Monitor - NVIDIA
> > > Geforce 7800 GTX". One of the displays is a 17'' Dell 1703 FPs
LCD and
> > > the other is an old 21'' Nokia Multigraph 445X CRT.
> > >
> > > I have both calibrated and profiled these monitors using
Spyder3. Then
> > > using Spyder3Pro software (Spyderproof) I have verified that the ICC
> > > profiles have been applied to their respective monitors. At
least when
> > > I switch back and forth between "before calibration" and "after
> > > calibration" the looks of the screen changes on both devices (to
> > > better). A recalibration check tells that both screens are  
> > > calibrated ok.
> > >
> > > They should now look the same, right?
> > > No, they don't.
> > >
> > > I even matched their brightness by trial and error (adjust,
calibrate,
> > > repeat until good). The CRT still has a yellow cast and the LCD
has a
> > > blue cast. Or maybe it's neutral, but relatively the CRT is
warmer. A
> > > lot. Then I thought that maybe the screens frame affects visual
> > > perception. I looked at the screens through a tube to exclude
> > > environmental effects. The CRT is warmer.
> > >
> > > Calibration (both monitors offer RGB adjustments that adjust color,
> > > somehow):
> > > LCD RGB=43%,43%,50% to produce pure white measured by Spyder.
> > > CRT RGB=56%,51%,46% measured. But if I change these *after*
> > > calibration and profiling to 45%,40%,52% then the screens look
more  
> > > like.
> > >
> > > So... adjusting RGB on these screens makes white purer on both
> > > devices, but if I want identical colors I need to set similar
> > > %-values. Oops. Profiling is not supposed to work like this, so
what's
> > > wrong?
> > >
> > > Any ideas would be much appreciated. Thanks.
> > >
> > >
> > > ------------------------------------
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> >
>