[argyllcms] Re: Continuous reading mode ambient light temperature

  • From: Jos van Riswick <josvanr@xxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Sun, 29 May 2011 22:49:15 +0200


thnx. but the biggest problem for my setup *is* temperature.... but yes,
using a number of different curves measured at different times of the day
is possible. Then write a script that takes an ambient temperature measurement,
and then pick the curve closest to the measured temperature... But still
a bit cumbersome.

And yes, controlling the enviroment light is the best option, but...
hmm It's kind
of not nice to spend all day in a darkened room with blue fluorescent
light, when
the sun is shining outside..... Also, I just feel that judging colors
in my paintings
is best done in day light..

I'm wondering if it isn't possible to just convert the measurements in
an icc monitor
file to a different temperature. ....


On Sun, May 29, 2011 at 2:47 PM, Roger Breton <graxx@xxxxxxxxxxxx> wrote:
> 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.

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