[Tig] MacBook Pro colorimetry

[glenn chan]

The panel I believe is 6-bit.  (Apple is currently in a lawsuit over
this since its advertising claims more colors than a 6-bit display is
capable of producing.)  It seems that all laptop displays are 6-bit
now.

Dithering techniques (there are many different techniques) can be used
to get rid of the appearance of banding.  Done really well, you can
have no banding with an increase in noise.  Inferior dithering
techniques can have their own artifacts.  e.g. a gradient that goes
from left to right has no artifacts (other than noise) while a
gradient that goes from top to bottom has visible lines going
horizontally.

In Colorsync:
In the default setting (the profile set to "Color LCD"), there is
(what appears to be) banding on gradients of certain colors.  It
doesn't matter what direction the gradients are.
There is some subtle noise that is barely visible (some people refer
to this as "sparklies").

If you change the color profile to sRGB (which should get around some
of the color management), the banding goes away.  Why?  I have no
idea.

2- Bottom line:

The limited color gamut is the most noticeable flaw.  If you have a
gradient going into fully saturated red/green/blue, the display will
very noticeably screw up on the saturated end.  This just doesn't cut
it.  For color work, you want a display with exactly Rec. 709 / sRGB
color gamut (or possibly larger).  *The ideal gamut (Rec.709/sRGB,
SMPTE C, EBU, P3, or "wide") depends on what you're trying to do.

You can attach another monitor to your MBP so you can bypass the
shoddiness of any laptop LCD.

3- I do not own a hardware calibration probe so my comments above just
refer to the factory calibration.

3b- To go on a digression... somehow I have a feeling that sometimes
the cheap products can do more harm than good (e.g. I've seen some
measurements where the green primary lies outside the spectral locus;
this is impossible, so the measurements must be erroneous).  But I
don't own these devices so I can't really speak from experience.


Glenn Chan
Toronto, Canada