[Tig] Do you Do It in the dark?
Tue Mar 1 22:05:34 GMT 2005
Yup I understand all of that, been there before.....
what you missed is that there is 'enough' D6500 light around and in
the room at low level to give a _constant_ and_unchanging_ visual reference.
In practice there is a fair bit of this illumination, even in a 'darkened' room.
illumination for the panel, clients, workspace writing areas, etc etc.
I am also aware that is easy to 'trick' the human visual system with
drifting tests etc. as you indicate, but we dont do this in our grading rooms.
Our monitoring is metered regularly and fixed, like everybody elses.
I think you have taken 'darkend room' too literally.
It will be interesting to see if you can manage an illuminated reference
surround 'significantly larger than the surface-area of the monitor' in a
DI projection theaterette.
I suspect the solution will be to have side areas/walls illuminated or else
a big big room
Martin Euredjian wrote:
> Thanks to Screen Time Images for supporting the TIG.
>>Grading in the dark should not be an issue. If the calibration has
> been done the colorist will perform......
> Despite reported success, it is a scientific fact that the human visual
> system is subject to many factors that conspire against you when viewing a
> monitor in the absence of a reference field.
> I've seen severe examples of this. One such test consisted of a computer
> displaying an image with a program that slowly varied color parameters. The
> rate of change was adjustable. At slow rates the human observer could not
> tell the difference in the absence of a reference field. Expert observers
> (what a color scientist would call a colorist) are not immune to this. Only
> when color-shift extremes were reached did observers start to notice
> Of course, this effect is easy to understand. Put on a pair of green
> sunglasses and go outside. Within a very short period of time your brain
> has adjusted for the shift in color and white is still white, red is still
> red, etc.
> And so, in the context of monitoring, without a reference field, it is quite
> possible to either have human-induced color drift or color drift caused by
> such things as the monitor drifting. A reference field, which should be
> significantly larger than the surface-area of the monitor --as well as
> designed and calibrated in context-- provides a constant reference not only
> for color but also for contrast and black level. Don't forget that, more
> often than not, more than one person is looking at images in a grading room.
> How are you calibrating your clients' visual system?
> SMPTE RP162 is one document that deals with this. I feel that it is
> somewhat outdated. Despite this, I think this is better than darkness.
> I think this is particularly important in another context: Distributed
> What happens when content must be viewed and judged at geographically
> distant locations? LA to London? Budapest to NYC? San Rafael to New
> Zealand? etc. A properly established surround field is of significant
> importance here in order to be able to even begin an attempt to discuss
> color. The same could be said about color decisions made on set brought
> into post.
> Now, from that broader context, I hope that it can be seen that unilaterally
> working in a dark environment might not guarantee best results. It could
> actually be dangerous. While you (plural) may have total trust in your
> colorist as the "reference entity" (a myth that I can dispel in about 15
> seconds flat --no offense meant), the very ability to communicate color
> reliably throughout the production and post-production process must be
> standards bases and these standards have to take into account the viewing
> environment because we humans do not see as a colorimeter does. We see in
> relation to other factors surrounding the subject. The print, paint and
> fabric industries have known this for a long time. They have standards and
> are very aware of such issues as viewer and instrument metamerism. It might
> be time to take a look at RP162 and bring it up to date so that everyone,
> from production to post, can understand what to do before attempting to
> either adjust or discuss color.
> Interestingly enough, we are going to have a calibrated viewing environment
> at the eCinema booth this year. A room with proper surround lighting.
> Being that I've landed right-smack in the middle of trying to make a new
> display technology play with the big boys I have to deal with this issue of
> viewing environment all the time. A great many lessons were learned so far.
> Some of which I hope to share during NAB.
> Martin Euredjian
> eCinema Systems, Inc.
> voice: 661-305-9320
> fax: 661-775-4876
> martin at ecinemasys.com
> ecinema at ieee.org
> participate in the tig wiki pages at http://tig.colorist.org/wiki
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> Tig at tig.colorist.org
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