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Posted by PTravel on 07/03/06 18:09
"Toby" <zdftokyo@gool.com> wrote in message
news:44a8d9ed$0$4833$bb4e3ad8@newscene.com...
>
> "PTravel" <ptravel@travelersvideo.com> wrote in message
> news:Ho4qg.79550$4L1.53201@newssvr11.news.prodigy.com...
>>
>> "Toby" <kymarto123@ybb.ne.jpp> wrote in message
>> news:44a8a56d$0$74509$bb4e3ad8@newscene.com...
>>>
>>> "PTravel" <ptravel@travelersvideo.com> wrote in message
>>> news:4p_pg.114415$H71.15484@newssvr13.news.prodigy.com...
>>>>
>>>> "Martin Heffels" <youwishyouwouldknow@nottellinya.com> wrote in message
>>>> news:hfiga2t7ffprp0nce5eu1mdldo0aa83lnt@4ax.com...
>>>>> On Sun, 02 Jul 2006 22:17:40 GMT, "PTravel"
>>>>> <ptravel@travelersvideo.com>
>>>>> wrote:
>>>>>
>>>>>>I was thinking more in line with the video equivalent of an audio
>>>>>>compander -- something that can take the limited range that's
>>>>>>available and
>>>>>>expand it. For example, if Na lights put out light limited to 240-245
>>>>>>angstroms (I'm just making up numbers here), something that would
>>>>>>extrapolate on the video so that the lower range fell closer to red
>>>>>>and the
>>>>>>upper range closer to blue would provide a more varied, albeit false,
>>>>>>coloration.
>>>>>>
>>>>>>Hmmm. Have I just invented a new filter?
>>>>>
>>>>> Want to have Ira Tiffen's e-mail address? :-)
>>>>>
>>>>> You could with some clever mathematics expand the range and fill in
>>>>> the gap
>>>>> on your computer,
>>>>
>>>> That's exactly my thought.
>>>
>>> To what end? Who would want such a thing? Besides, you would end up with
>>> a horrible posterization effect. Imagine trying to recreate 16 bit color
>>> from 4 bit color information...
>>
>> I've never understand a question like this.
>>
>> I would want something like this. To my own end. Does this bother you?
>
> Not at all, but I'm pointing out that if you want it you'll probably have
> to develop it yourself, unless you are a particulary smooth talker.
>>
>> As for posterization, I don't think so.
>
> Well, yes indeed. You need to create levels where none exist. I suppose
> you could do some fancy interpolation to blur the edges, but you are still
> going to have to create something out of nothing, so to speak. You are
> talking about taking minute chroma differences and stretching them across
> the RGB plane, so to speak. Where are you going to get all those extra
> gradations?
What I propose is no different than expanding dynamic range in an audio
compander. A 1/10th nm difference would be expanded into a 1 nm difference,
etc. It would not result in posterization, as the number of discrete levels
is not being reduced.
>
> I watched your video (by the way, you can get a small bubble level as a
> keychain. Don't get a round one - you only want to check horizontal, not
> vertical, when you mount it on a camera). You have lots of mixed light
> there. What do you plan to do when you have incandescent at 2700K and
> fluorescent at anywhere between 3200-4700K? What happens to those colors
> when you expand your sodium (non) spectrum?
I used my video as an example only of the monochromatic effect that results
from shooting under Na lights.
>
> I don't really mean to rain on your parade, but it's not so simple as you
> seem to think.
I never said it was simple. I do think, though, that you don't know what I
have in mind.
>
> Toby
>
>
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