[argyllcms] Re: Continuous reading mode ambient light temperature

  • From: Roger Breton <graxx@xxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 29 May 2011 08:47:57 -0400

Jos,

Depending on the OS, I can see a small application that continuously reads
ambient light levels and switches monitor profiles around, when needed, but
you would only have a few monitor profiles, not make a new monitor profile
continuously? Like, you would have to characterize the ambient light in your
studio, say, at different times of the day. Say you identified 5 or 6
different distinct illumination levels, like 32 lux or 64 Lux or 128 Lux or
256 Lux. Keep the "color" of the light out of the equation for now. You
could create 1 monitor profile, keeping the same calibration, for those 4
different levels of ambient illumination. Then, you have a small application
that continuously monitor the level of ambient lighting. When the light
falls into, say, into 128 Lux territory, it would change the system's
monitor profile, and so on. But if you were to do it continuously, it would
require two instruments, or you would have to have an instrument that you
could leave attached to the screen that could have two sensors: one facing
you, to measure ambient light, and another, facing the monitor, to measure
the display . As soon as it detects a noticeable change in ambient level, it
would launch Argyll to create a new monitor profile and set it as the new
default system profile, and so on. Hueys are so cheap that you could almost
afford to have two instruments, one for making monitor profiles, that you
leave attached to the screen permanently, and another that would measure
ambient light, that you can leave on your desk. It would require some
programming but it would work. For your application, you night like the idea
of those monitor profiles that have a sensor to monitor ambient light
changes. But does the monitor manufacturer provide an SDK so that you can
program this yourself? And, come to think of it, it is cheaper to buy a
second Huey than a new monitor with ambient level measurement capabilities
buil-in? 

Roger

-----Original Message-----
From: argyllcms-bounce@xxxxxxxxxxxxx [mailto:argyllcms-bounce@xxxxxxxxxxxxx]
On Behalf Of Jos van Riswick
Sent: May-29-11 4:34 AM
To: argyllcms@xxxxxxxxxxxxx
Subject: [argyllcms] Re: Continuous reading mode ambient light temperature

Reason is: I'm an artist (painter, see www.josvanriswick.nl ) and
occasionally I use photographic reference material to paint from.
So what I do is constantly compare the colors in my painting and in the
reference. Using a computer monitor seemed ideal for me, because  I can
change the reference's colors to my liking, unlike with a print. But
unfortunately, the temperature of the light outside keeps changing. So a
painting that I started in the morning, will look completely different from
the image in the monitor later in the day. I tried to use artificial light
(constant) but didn't suit me. (kind of depressing). What I tried yesterday
is just manually adjust the rgb gains of the monitor now and then, and
compare a white image to a patch of white paint. This really makes a
difference,  but is kind of cumbersome.


So I'd really like to find a way to do this. I have a huey pro colorimeter,
which is able to take ambient light temperature measurements. I tried to do
this with 'spotread -a'. Seems to work.. I'm kind of handy with writing perl
scripts. So maybe I can write a script to read the temperature, adjust a
previously measured curve and then just apply it again with dispwin. Then
run the script when the discrepancy becomes too disturbing.

So if you have any suggestions on how to do to the calculations needed, or
what programs I could look into, would be welcome....


 Jos

>
> Hi,
>    Why would you want to do that ? -i.e. it may be a good gimmick, but 
> I'm not aware of any serious color reason to do something like that.
> The assumption is that if you are looking at a monitor, your eyes are 
> mostly adapted to the display, since it dominates your field of view.
> In addition, there are serious trade-offs to be made in calibrating a 
> display to a particular color temperature, such a reduced brightness, 
> loss of resolution in the channels etc., and in addition there is the 
> issue of how to make the profile track the change in display 
> calibration, and no applications (as far as I know) have any facility 
> to dynamically update the profile they are using.
>
> Graeme Gill.
>
>


Other related posts: