VC Language - Yellow Color Range

Author

Yellow Color Range

Jack

2006-05-25, 4:19 am

Hi,
Maybe it's a bit OT, I have been programming in VC++
and wondering what the color yellow range is in hex
say 1560000 to 2000001 can be regarded as Yellow
Thanks
Jack

Jack

2006-05-25, 4:19 am

Also, I am looking at the CIE System
Does anyone know what the ranges of yellow are for the CIE system?
Thanks
Jack

"Jack" <jl@knight.com> ¼¶¼g©ó¶l¥ó·s»D:O92ABX9fGHA.1264@TK2MSFTNGP05.phx.gbl...
> Hi,
> Maybe it's a bit OT, I have been programming in VC
> and wondering what the color yellow range is in hex
> say 1560000 to 2000001 can be regarded as Yellow
> Thanks
> Jack
>

David Webber

2006-05-25, 4:19 am

"Jack" <jl@knight.com> wrote in message
news:O92ABX9fGHA.1264@TK2MSFTNGP05.phx.gbl...

> Maybe it's a bit OT, I have been programming in VC++
> and wondering what the color yellow range is in hex
> say 1560000 to 2000001 can be regarded as Yellow

1. The colours are represented as a red/green/blue mixture in the
hexadecimal form

rrggbb

where each letter represents a hex digit. rr is the red component gg is
the green component, and bb is the blue component.

So "everything"

FFFFFF = white

and "nothing"

0000000 = black

xyxyxy will have the same amount (xy) of each and be a shade of grey.

The eye perceives yellow in the same way as a mixture of green and red, and
so

abxy00

will be a yellowish shade with

FFFF00

being bright saturated yellow. Adding some blue

FFFFxy

will lighten it as xy goes from 00 to FF through cream to white.

But any

abcdxy

will be a yellowish tinge as long as

ab >> xy
cd >> xy

with ab approximately equal to cd.

2. The reason it works like this is that the eye has three kinds of sensor
which fire primarily on red, green, and blue, but each responds to a range
of frequencies and they overlap. But in simple terms

Red light fires the red sensor
Green light fires the green sensor

Yellow light, which has a frequency intermediate between red and green,
fires both. Thus we are incapable of telling the difference between yellow
light and a mixture of red and green, just because of the way the eye works.
The whole concept of mixing light or pigment to create colour is based, not
on light, but on the biology of the eye.

IIRC the octopus has four kinds of sensor in its eye, and can therefore
distinguish a complete extra dimension of colour. Creatures which have
only one, only see in monochrome.

Dave
--
David Webber
Author MOZART the music processor for Windows -
http://www.mozart.co.uk
For discussion/support see
http://www.mozart.co.uk/mzusers/mailinglist.htm

Jack

2006-05-25, 4:19 am

tried this
====================
for (int i = 0; i < ds.dsBm.bmHeight; i++) {
for (int j = 0; i < ds.dsBm.bmWidth; j++) {
if (pBitmap[i][j] == RGB(255,255,0)) <<< failed this (pBitmap[i][j] was
not correctly stated)
AfxMessageBox ("Hit it", MB_OK, NULL);

}
}
=====================
"David Webber" <dave@musical.demon.co.uk> ¼¶¼g©ó¶l¥ó·s»D:e93$Fu9fGHA.4864@TK2MSFTNGP05.phx.gbl...
>
> "Jack" <jl@knight.com> wrote in message
> news:O92ABX9fGHA.1264@TK2MSFTNGP05.phx.gbl...
>
>
> 1. The colours are represented as a red/green/blue mixture in the
> hexadecimal form
>
> rrggbb
>
> where each letter represents a hex digit. rr is the red component gg is
> the green component, and bb is the blue component.
>
> So "everything"
>
> FFFFFF = white
>
> and "nothing"
>
> 0000000 = black
>
> xyxyxy will have the same amount (xy) of each and be a shade of grey.
>
> The eye perceives yellow in the same way as a mixture of green and red,
> and so
>
> abxy00
>
> will be a yellowish shade with
>
> FFFF00
>
> being bright saturated yellow. Adding some blue
>
> FFFFxy
>
> will lighten it as xy goes from 00 to FF through cream to white.
>
> But any
>
> abcdxy
>
> will be a yellowish tinge as long as
>
> ab >> xy
> cd >> xy
>
> with ab approximately equal to cd.
>
> 2. The reason it works like this is that the eye has three kinds of sensor
> which fire primarily on red, green, and blue, but each responds to a range
> of frequencies and they overlap. But in simple terms
>
> Red light fires the red sensor
> Green light fires the green sensor
>
> Yellow light, which has a frequency intermediate between red and green,
> fires both. Thus we are incapable of telling the difference between
> yellow light and a mixture of red and green, just because of the way the
> eye works. The whole concept of mixing light or pigment to create colour
> is based, not on light, but on the biology of the eye.
>
> IIRC the octopus has four kinds of sensor in its eye, and can therefore
> distinguish a complete extra dimension of colour. Creatures which have
> only one, only see in monochrome.
>
> Dave
> --
> David Webber
> Author MOZART the music processor for Windows -
> http://www.mozart.co.uk
> For discussion/support see
> http://www.mozart.co.uk/mzusers/mailinglist.htm
>
>
>
>
>
>
>
>
>

Alex Blekhman

2006-05-25, 8:16 am

David Webber wrote:
> [...]
> IIRC the octopus has four kinds of sensor in its eye, and
> can therefore distinguish a complete extra dimension of
> colour.

Strictly speaking, it's not sensor but special pigment on
onctopus' retina which can change orientation of sensor
cells, hence the ability of polarization discrimantion. So,
octopus can percieve another "dimension" of polarized light.
P-vision helps octopus to prey otherwise nearly invisible
plankton and jellyfishes.

David Webber

2006-05-25, 7:08 pm

"Alex Blekhman" <tkfx.N05P4M@yahoo.com> wrote in message
news:OWwZMm%23fGHA.1520@TK2MSFTNGP03.phx.gbl...

> Strictly speaking, it's not sensor but special pigment on onctopus' retina
> which can change orientation of sensor cells, hence the ability of
> polarization discrimantion. So, octopus can percieve another "dimension"
> of polarized light. P-vision helps octopus to prey otherwise nearly
> invisible plankton and jellyfishes.

Thanks for the clarification - it was something I became vaguely aware of
years ago and was lurking in the abyssal domain which is my memory :-)

Dave
--
David Webber
Author MOZART the music processor for Windows -
http://www.mozart.co.uk
For discussion/support see
http://www.mozart.co.uk/mzusers/mailinglist.htm

David Webber

2006-05-25, 7:08 pm

"Jack" <jl@knight.com> wrote in message
news:%232rQxA%23fGHA.4940@TK2MSFTNGP05.phx.gbl...

> tried this
> ====================
> for (int i = 0; i < ds.dsBm.bmHeight; i++) {
> for (int j = 0; i < ds.dsBm.bmWidth; j++) {
> if (pBitmap[i][j] == RGB(255,255,0)) <<< failed this (pBitmap[i][j] was
> not correctly stated)
> AfxMessageBox ("Hit it", MB_OK, NULL);
> }
> }
> =====================

Not completely sure what you're attemppting here but there surely shouldn't
be an 'i' specifying the termination of second (inner) 'for' loop.

Dave
--
David Webber
Author MOZART the music processor for Windows -
http://www.mozart.co.uk
For discussion/support see
http://www.mozart.co.uk/mzusers/mailinglist.htm

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