Posted by Toby on 07/03/06 08:51

"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?

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 don't really mean to rain on your parade, but it's not so simple as you
seem to think.

Toby

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