 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
There are two light sources, pure red and green, practically coincident and
pointing in the same direction. You place a filter that's a perfect yellow
blocker in the path. What colour light would you see past the filter?
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
yellow?
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Le 30/12/2009 14:30, somebody nous fit lire :
> There are two light sources, pure red and green, practically coincident and
> pointing in the same direction. You place a filter that's a perfect yellow
> blocker in the path. What colour light would you see past the filter?
My answer: I would perceive yellow.
If I was a prism, I would get a red and a green ray.
Hypothesis: red source is a spectral ray in red
green source is a spectral ray in green
yellow blocker is a spectral blocker in the yellow lightwave, as it is
perfect, it does not stop rays in red or green spectrum.
So both rays go through.
Then my imperfect eyes get excited by the red & green rays, (triggering
the red & green spectral-large cones), information get transmitted to
the brain which has no way to separate that flux from an actual yellow
light, so will interpret it along the simplest way: it's a yellow light.
Of course, I assumed you ask me as a average human. If I was a bee or a
dog (on internet, how could you know), or colour-blind, my answer would
be different.
Last point, you did not talk about the intensity of each light sources...
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
somebody <x### [at] y com> wrote:
> You place a filter that's a perfect yellow blocker in the path.
What's a "yellow blocker"? It allows all other wavelengths to pass except
yellow?
--
- Warp
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
"Le_Forgeron" <jgr### [at] freefr> wrote in message
news:4b3b5ebf$1@news.povray.org...
> Le 30/12/2009 14:30, somebody nous fit lire :
> > There are two light sources, pure red and green, practically coincident
and
> > pointing in the same direction. You place a filter that's a perfect
yellow
> > blocker in the path. What colour light would you see past the filter?
> My answer: I would perceive yellow.
> If I was a prism, I would get a red and a green ray.
> [...]
> Last point, you did not talk about the intensity of each light sources...
I knew I could not trick this crowd!
In general, I have a beef with 3-color models being taught as physical
models instead of a model only for the human visual system. Even
professionals who should know better often fail to differentiate the two.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
somebody wrote:
> There are two light sources, pure red and green, practically coincident and
> pointing in the same direction. You place a filter that's a perfect yellow
> blocker in the path. What colour light would you see past the filter?
You realise there's a difference between a binary-yellow filter and a
unary-yellow filter, right? You haven't specified which one.
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 31-12-2009 12:16, Orchid XP v8 wrote:
> somebody wrote:
>> There are two light sources, pure red and green, practically
>> coincident and
>> pointing in the same direction. You place a filter that's a perfect
>> yellow
>> blocker in the path. What colour light would you see past the filter?
>
> You realise there's a difference between a binary-yellow filter and a
> unary-yellow filter, right? You haven't specified which one.
>
You mean high-pass or band pass?
BTW welcome back. Skiing again?
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
>> You realise there's a difference between a binary-yellow filter and a
>> unary-yellow filter, right? You haven't specified which one.
>>
> You mean high-pass or band pass?
I mean there are filters that pass the whole band from red to green, and
there are other filters that only pass the narrow band of yellow
wavelengths in the middle.
If you pass a beam of light containing a single yellow peak through the
latter kind of filter, you get yellow. If you pass a bean containing
seperate red and green peaks through the same filter, you get
(hypothetically) black.
> BTW welcome back. Skiing again?
No, just staying with relatives for a few days over Christmas. ;-)
--
http://blog.orphi.me.uk/
http://www.zazzle.com/MathematicalOrchid*
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> In general, I have a beef with 3-color models being taught as physical
> models instead of a model only for the human visual system. Even
> professionals who should know better often fail to differentiate the two.
It also becomes an issue with the human visual system when you are using
(near-)monochromatic light sources to illuminate surfaces that are seen by
humans (eg LED lighting). It's best to work with the spectral data whenever
you can, and only convert to a 3-colour model right at the end.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On 12/30/09 18:50, somebody wrote:
> In general, I have a beef with 3-color models being taught as physical
> models instead of a model only for the human visual system. Even
> professionals who should know better often fail to differentiate the two.
Along with the whole 7 colors in a rainbow...
--
I'm addicted to placebos. I'd give them up, but it wouldn't make any
difference. - Steven Wright
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
