Luminance Problem in Calibrating an LCD Monitor

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One4All - 12 Jul 2006 04:00 GMT

Wait, wait! Altho this is a techie question, I know most, if not all,
of you are using lcd monitors, by now, in your digital color workflows.
Maybe none of you have calibrated/profiled your lcd's. If so, I deserve
a 0 response. But, if any of you have done so, I'd like to know how you
got your luminance reading to meet the 140 that is generally the
standard for lcd monitors.

I have a Dell 2005FPW lcd monitor, Mac G5 running OS 10.3.9. I'm trying
to calibrate/profile the monitor with Eye-One Photo running Match 3.6
software. I've reduced the brightness control on the monitor to 0, but
even so, the luminance remains high at 180. I'm aware that I could
reduce the respective RGB readings by a certain percent, but I'm also
aware this introduces other problems.

The Dell offers no contrast control. (Hopefully, many of you know what
I'm talking about.) I've decided that, since my color temp. (6500K) and
gamma (2.2) meet the lcd standards, for luminance, I'll set a
customized value of 180, which is the value Eye-One returns for this
monitor with brightness reduced to 0. In other words if the monitor's
value cannot meet the standard value, then change the standard value to
meet the monitor's value.

The whole purpose of all this is to produce a monitor profile that
accurately describes the monitor's behaviour, whatever that behaviour
is, whether it meets specs, or not. Isn't that right? If any of you
have resolved this lcd luminance problem, I'd like to know how you did
it. If you resolved it the way I'm thinking of resolving it, or if you
resolved it differently, I'd like some feedback.

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MLIDDELL - 14 Jul 2006 15:02 GMT

As far as I know you cannot calibrate most 'normal' lcd screens. Moving
your angle of view only slightly changes the colours and contrast.
Monitors like EIZO ColorEdge lcds do not have this problem and are
calibrated right out of the box.

I run dual screens, one crt and on lcd. All my editing is done with my
image on the calibrated crt.

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Greg - 14 Jul 2006 16:35 GMT

> As far as I know you cannot calibrate most 'normal' lcd screens. Moving
> your angle of view only slightly changes the colours and contrast.
[quoted text clipped - 3 lines]
> I run dual screens, one crt and on lcd. All my editing is done with my
> image on the calibrated crt.

You can calibrate LCD screens using the Color Spyder, Color Eye
and various other devices along the same lines. I currently have no
issues getting my output very close to my on screen LCD image on an
uncalibrated monitor when the image comes from my digital camera
however scans are a little more troublesome.

Signature

Reality-Is finding that perfect picture
and never looking back.

www.gregblankphoto.com

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One4All - 14 Jul 2006 20:19 GMT

> > As far as I know you cannot calibrate most 'normal' lcd screens. >

> You can calibrate LCD screens using the Color Spyder, Color Eye
> and various other devices along the same lines. I currently have no
> issues getting my output very close to my on screen LCD image on an
> uncalibrated monitor when the image comes from my digital camera
> however scans are a little more troublesome.

So, I assume you haven't made a custom profile of your monitor. If you
have made such a profile, did you base it on your uncalibrated monitor?
If so, what monitor values did you use for color temp., gamma, &
luminance? The luminance value is what I'm interested in.

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Greg - 15 Jul 2006 00:54 GMT

> > > As far as I know you cannot calibrate most 'normal' lcd screens. >
>
[quoted text clipped - 8 lines]
> If so, what monitor values did you use for color temp., gamma, &
> luminance? The luminance value is what I'm interested in.

No I have not, however I have an excellent perception of neutral grey,
it gotten me through 22+ years of color darkroom. If you understand what
is happening in PS with curves and levels I feel you can get away with
an uncalibrated monitor-but I also think it makes thing easier. Making a
few prints to get a excellent one never bugged me so ,.....

Like I said a color spyder or other does all these things, perhap my
next purchase. Your luminance value should fairly easy to find if you
can measure a grey card (scan) maybe using a spot meter???

Signature

Reality-Is finding that perfect picture
and never looking back.

www.gregblankphoto.com

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Raphael Bustin - 15 Jul 2006 05:01 GMT

>> > As far as I know you cannot calibrate most 'normal' lcd screens. >
>
[quoted text clipped - 8 lines]
>If so, what monitor values did you use for color temp., gamma, &
>luminance? The luminance value is what I'm interested in.

There's no real issue calibrating and profiling a decent LCD monitor.
I use a Gretag Eye-1 on mine.

Gamma 2.2 and white point 6500K is about all you need to know.

My Samsung LCD (213T) needed to have the brightness turned
down considerably -- not for calibration purposes, per se, but
because the default setting was so bright as to be painful.

AFAIK, there's no hard and fast rule for setting luminance
prior to profiling. The right setting depends in part on the
ambient light in your work area. "Conventional wisdom"
was to have a dark or dimly lit work area, so that low or
moderate levels of screen luminance were in order.

Your iris adjusts according to ambient light. So the screen
luminance has to be set accordingly.

Yes, there are issues with off-axis viewing. The simple "fix"
is to use your head -- literally. That is, make sure that your
line-of-sight is normal (perpendicular) to the point of interest.

rafe b
www.terrapinphoto.com

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Neil Gould - 15 Jul 2006 12:01 GMT

Recently, One4All <dwerner@bresnan.net> posted:

>>> As far as I know you cannot calibrate most 'normal' lcd screens. >
>
[quoted text clipped - 8 lines]
> monitor? If so, what monitor values did you use for color temp.,
> gamma, & luminance? The luminance value is what I'm interested in.

Luminance values will vary for different make and model of monitors, LCDs
included. So, getting "a number" from someone is likely to have no
relevance to your setup.

How the monitor luminance appears is relative to the ambient light in the
room, so it's a good idea to set comfortable brightness levels, both in
the room and on-screen prior to calibrating your monitor (keeping in mind
that color temperature may be affected by the brightness, and may appear
differently depending on the color of the ambient light as well).

If profiles are available, they are typically supplied by the
manufacturer... this is a different issue from calibration. LCD monitors
intended for graphics works are supplied with profiles, and can be easily
calibrated if they are used with a decent graphics card.

Regards,

Neil

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no_name - 17 Jul 2006 03:14 GMT

> Wait, wait! Altho this is a techie question, I know most, if not all,
> of you are using lcd monitors, by now, in your digital color workflows.

Nope. Calibrated CRT.

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