What wavelength is white?

[Phredy1]

No need to apologize man! It's a cool concept that not many people think about and 99.999% of people just take for granted. If I tried to strike up this topic with most of my friends or family, they'd probably try to organize some kind of intervention..., but I think it's great
-Mike

To tell you what kind of a night it was, I fed my cat last night. This morning I looked and there was still the same amount of cat food in his bowl and he was sitting by his food giving me the stinky eye look. I looked at the food and it didn't look right, so I checked and I had given him a can of bean dip by mistake. LOL

[mikkojay]

Not too shabby for a Wednesday That reminds me- I have tickets to go see RUSH on 8/25, and that's on a Wednesday- I'd better put in for the following day off.
Have a good one,
Mike

[swamidog]

you're lucky he only gave you the stink eye!

To tell you what kind of a night it was, I fed my cat last night. This morning I looked and there was still the same amount of cat food in his bowl and he was sitting by his food giving me the stinky eye look. I looked at the food and it didn't look right, so I checked and I had given him a can of bean dip by mistake. LOL

[allthatwhichis]

Not too shabby for a Wednesday That reminds me- I have tickets to go see RUSH on 8/25, and that's on a Wednesday- I'd better put in for the following day off.
Have a good one,
Mike

F it, I'd take Friday off as well.

[Synce]

Budweiser

Bud heavy!

15

[kitatit]

Shit...I apologize. I knew better than to post something after that last Budweiser.

The answer is clear today. Combining red and green does not change the wavelengths. There is still only 532nm and 640nm wavelengths. It just appears yellow to the eye. Much the same as pixels on a tv screen.

WTF was I thinking? LOL

To tell you what kind of a night it was, I fed my cat last night. This morning I looked and there was still the same amount of cat food in his bowl and he was sitting by his food giving me the stinky eye look. I looked at the food and it didn't look right, so I checked and I had given him a can of bean dip by mistake. LOL

Ha! Pissing myself laughing! I'm really picturing the expression on your cats face

Just check you haven't left the coat hanger in your shirt, that can really start to chafe after a while.

No need to apologize man! It's a cool concept that not many people think about and 99.999% of people just take for granted. If I tried to strike up this topic with most of my friends or family, they'd probably try to organize some kind of intervention..., but I think it's great
-Mike

To true. That's what is so great about PL. I feel at home here. There are so many people on the same wavelength( pardon the pun) that want to talk tech.

When I'm here my little voice isn't saying "don't talk about lasers,don't talk about lasers"

Hey while we are answering ponderous questions...

How do the pigments in paints work to reflect different colours?

[allthatwhichis]

How do the pigments in paints work to reflect different colours?

I started to wonder about that once I realized R + G + B are the "primary" light colors... yes additive, but don't complicate things.

Why are R, B, and Y the primary pigment colors?

[Doc]

I started to wonder about that once I realized R + G + B are the "primary" light colors... yes additive, but don't complicate things.

Why are R, B, and Y the primary pigment colors?

Almost, subtractive colour generally uses cyan magenta and yellow; the 'in between' colours. So for instance when mixing cyan and magenta the cyan absorbs the red light and the magenta absorbs the green light which leave only the blue reflected.

[allthatwhichis]

Almost, subtractive colour generally uses cyan magenta and yellow; the 'in between' colours. So for instance when mixing cyan and magenta the cyan absorbs the red light and the magenta absorbs the green light which leave only the blue reflected.

I said don't complicate things...

[buffo]

Why are R, B, and Y the primary pigment colors?

As Doc mentioned, because when you deal with ink (or pigment), you are dealing with subtractive color, whereas when you deal with light, you are dealing with additive color. Sorry dude, but there's no simpler way to say it.

When you mix light, the result is brighter. When you mix dye or pigment, the result is darker. (For simplicity's sake, we'll ignore the option of adding titanium white, since strictly speaking that isn't a "color", but more of a way to dilute an existing dye or pigment.)

Think about it this way: Red dye absorbs all other colors and only reflects red. (OK, it reflects a range of colors, but most of them are red or reddish. Very few of the other wavelengths, like green or blue, are reflected from a red dye. Those colors are absorbed for the most part.) So when you shine a white light on a piece of paper that has been dyed red, it looks red because the only color light that gets reflected off it is red.

If you shine a blue light onto red paper, it looks black, because the blue is absorbed, and there is no red light coming from your blue lamp to reflect off the red paper.

So what happens if you spill green dye on your red paper? Now you've got a spot that absorbs all colors except green, but it's on paper that already absorbs blue and green. So now you get a dark, nearly black spot, because the two dyes together are able to absorb all the colors of the spectrum.

That's subtractive color for you. Dyes subtract colors from the incoming light. The more different color dyes you add, the fewer colors will be reflected and the darker the object will appear.

Conversely, mixing light (or luminous sources) works the other way. Start with a pure red light, and everything looks red because that's the only color available to reflect off of them. Green and blue objects, which absorb most of the red light that fall on them, appear very dark - almost black - when lit with a red lamp.

But add a little green light to your red light, and now suddenly you have yellow illumination. A white piece of paper will reflect both red and green, so it looks yellow, but a red object will still look red (because it's reflecting the red) and a green object will look green (because it will reflect the green light). Now add some blue light, and you'll see all colors correctly.

Thus having different colors of light available ADDS to the number of colors you can see. (Additive color - get it?)

Adam