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color temp a defacto filter?

 
 
drs@canby.com
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      02-20-2005
This isn't limited to digital photography. How appropriate is it to
consider color temperature a filter? And to what extent is the missing
or added portions of the color spectrum significant? Even with proper
white balance are data lost (or added?) at 3000 K when compared to
8000 K?
 
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Joseph Meehan
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      02-20-2005
http://www.velocityreviews.com/forums/(E-Mail Removed) wrote:
> This isn't limited to digital photography. How appropriate is it to
> consider color temperature a filter? And to what extent is the missing
> or added portions of the color spectrum significant? Even with proper
> white balance are data lost (or added?) at 3000 K when compared to
> 8000 K?


The real answer is this. Try it yourself and see if it is significant
to you in the work you do. Other than that you can get thee other answers.
Someone else's evaluation of the issue based on their equipment, shooting
conditions and personal judgment, a technically correct answer with lots of
numbers which are meaningless in the real world or a pure guess.

--
Joseph Meehan

26 + 6 = 1 It's Irish Math


 
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C J Campbell
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      02-21-2005

<(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> This isn't limited to digital photography. How appropriate is it to
> consider color temperature a filter? And to what extent is the missing
> or added portions of the color spectrum significant? Even with proper
> white balance are data lost (or added?) at 3000 K when compared to
> 8000 K?


White balance is not at all like a filter. A filter subtracts portions of
the spectrum before the light reaches your lens. White balance is an
interpretation of that spectrum. The camera is a machine. It records
whatever photons strike the imaging material. It has no idea what color
those photons are. Whenever you take a picture, all the light is recorded.
Nothing is subtracted in order to adjust white balance.


 
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drs@canby.com
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      02-21-2005
On Sun, 20 Feb 2005 16:06:36 -0800, "C J Campbell"
<(E-Mail Removed)> wrote:

>
><(E-Mail Removed)> wrote in message
>news:(E-Mail Removed).. .
>> This isn't limited to digital photography. How appropriate is it to
>> consider color temperature a filter? And to what extent is the missing
>> or added portions of the color spectrum significant? Even with proper
>> white balance are data lost (or added?) at 3000 K when compared to
>> 8000 K?

>
>White balance is not at all like a filter. A filter subtracts portions of
>the spectrum before the light reaches your lens. White balance is an
>interpretation of that spectrum. The camera is a machine. It records
>whatever photons strike the imaging material. It has no idea what color
>those photons are. Whenever you take a picture, all the light is recorded.
>Nothing is subtracted in order to adjust white balance.
>

I'm assuming that different color temperatures are related to
differences in photon spectra that strike the sensor. Correct? And
doesn't that imply that some temps would not have the range of photons
that others would have? What I'm trying to find out is if the image
has more "color" at certain temperatures. I'm tempted to say photon
saturation but I doubt that's the right term. In other words, can you
extract the same range of color from a properly exposed photo taken at
3000 K as one taken at 8000 K?
 
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googlegroups2sucks
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      02-21-2005
good question. i think you can, though i can't say for certain... as
long as the quantity of light is the same, the quality (tungsten vs.
daylight) of the light shouldn't affect the extractable range, barring
any inherent equipment prefrences...i think.

i have a question. why can i easily distinguish between different
notes in music but go bananas trying to distinguish RGB levels for any
given color? is it just me, or do many have problems with color
correcting?

 
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C J Campbell
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      02-21-2005

<(E-Mail Removed)> wrote in message
news(E-Mail Removed)...
> >

> I'm assuming that different color temperatures are related to
> differences in photon spectra that strike the sensor. Correct? And
> doesn't that imply that some temps would not have the range of photons
> that others would have?


Well, suppose all your light comes from the red spectrum. No amount of
correction is going to bring back the blue and green colors. You cannot
record something that is not there. If you walk into a grocery store lit
with fluorescent lighting then you are not going to be able to see
everything that you would have with tungsten lighting. If elements of the
spectrum are missing in the lighting, neither your eyes nor a camera can
restore them.

I found it very difficult, myself, adjusting to your world's yellow sun.
Everything looks so much different than it does under the blue-white sun of
my planet, even with the special filters in my third eyelids.


 
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Owamanga
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      02-21-2005
On Mon, 21 Feb 2005 05:38:13 -0800, "C J Campbell"
<(E-Mail Removed)> wrote:

>
><(E-Mail Removed)> wrote in message
>news(E-Mail Removed).. .
>> >

>> I'm assuming that different color temperatures are related to
>> differences in photon spectra that strike the sensor. Correct? And
>> doesn't that imply that some temps would not have the range of photons
>> that others would have?

>
>Well, suppose all your light comes from the red spectrum. No amount of
>correction is going to bring back the blue and green colors. You cannot
>record something that is not there. If you walk into a grocery store lit
>with fluorescent lighting then you are not going to be able to see
>everything that you would have with tungsten lighting. If elements of the
>spectrum are missing in the lighting, neither your eyes nor a camera can
>restore them.
>
>I found it very difficult, myself, adjusting to your world's yellow sun.
>Everything looks so much different than it does under the blue-white sun of
>my planet, even with the special filters in my third eyelids.


You should have noticed on your way here that our Sun is actually
white. Only when seen through our atmosphere does it appear yellow, we
needed to scatter out some of the blue to make the sky that color.

Presuming your sun is white too, yet it appears blueish from the
planet surface, I'm guessing your home planet's daylight skies are a
reddy-yellowish color.

BTW, no matter what the English tell you, just because you have a
Scottish name doesn't *actually* mean you come from another planet -
just that it seems that way to some.

--
Owamanga!
 
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Larry
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      02-21-2005
In article <(E-Mail Removed) .com>,
(E-Mail Removed) says...
> good question. i think you can, though i can't say for certain... as
> long as the quantity of light is the same, the quality (tungsten vs.
> daylight) of the light shouldn't affect the extractable range, barring
> any inherent equipment prefrences...i think.
>
> i have a question. why can i easily distinguish between different
> notes in music but go bananas trying to distinguish RGB levels for any
> given color? is it just me, or do many have problems with color
> correcting?
>
>


Your EARS are MUCH more discriminating than your eyes.

Think of this... the picture on your TV is flickering at a rate of 30 times a
second (US NTSC) or 25 times a second (PAL) but you manage to watch it
anyhow.. If the music from your cd player did the same thing you would go
NUTS looking for the source of the hum/noise.

Color correcting/color timeing IS NOT AS EASY AS YOU WOULD THINK!


--
Larry Lynch
Mystic, Ct.
 
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paul
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      02-21-2005
googlegroups2sucks wrote:
> good question. i think you can, though i can't say for certain... as
> long as the quantity of light is the same, the quality (tungsten vs.
> daylight) of the light shouldn't affect the extractable range, barring
> any inherent equipment prefrences...i think.
>
> i have a question. why can i easily distinguish between different
> notes in music but go bananas trying to distinguish RGB levels for any
> given color? is it just me, or do many have problems with color
> correcting?



I think I read that the human eye has built in white balance correction
so we naturally try to make things look normal. Certainly we adjust for
exposure.
 
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Larry
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      02-21-2005
In article <(E-Mail Removed)>, (E-Mail Removed) says...
> googlegroups2sucks wrote:
> > good question. i think you can, though i can't say for certain... as
> > long as the quantity of light is the same, the quality (tungsten vs.
> > daylight) of the light shouldn't affect the extractable range, barring
> > any inherent equipment prefrences...i think.
> >
> > i have a question. why can i easily distinguish between different
> > notes in music but go bananas trying to distinguish RGB levels for any
> > given color? is it just me, or do many have problems with color
> > correcting?

>
>
> I think I read that the human eye has built in white balance correction
> so we naturally try to make things look normal. Certainly we adjust for
> exposure.
>


We do have "built in" white balance..

Go for a walk in a leafy forest with a friend who is wearing a white shirt.
Almost instantaneously the shirt will appear white although most of the
available light is coming through a green filter.

Without any "white balance" the shirt will photograph greenish, but you wont
notice it while you are walking through the forest.

This is only one example and perhaps not the best example, but it is one that
is EASY to try for most people.


--
Larry Lynch
Mystic, Ct.
 
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