Black is the lack of color when you are using Additive color model used when you are
producing light. Black is all colors when you are using Subtractive color model. 

http://en.wikipedia.org/wiki/Subtractive_color

The difference is a monitor uses Additive, a painting uses Subtractive. Does the item produce light or reflect?

Kanaswind 

Nocturnal said: Which is why a white car is cooler than a black car. 

Only in a thermodynamics sort of way....

As mentioned there is additive and subtractive color changes done by substances. If you take two colors of paint, and mix them to create a third, it is subtractive tinting. Each paint tint absorbs different wavelengths (colors).  If you take the same two colors, but this time as colored light, and shine them together on a white surface, you won't get the same tint that you got with the mixed paint.  Shining two lights together is adding wavelengths to the mix, rather than the way paint mixes absorb additional wavelengths. 

I learned about this in my physics classes, but there's lots of web references available that discuss it. For example,

http://home.att.net/~RTRUSCIO/COLORSYS.htm 

What's this mean?

It means a black surface is a surface that absorbs all visible light wavelengths. As the fabric fades, and turns "grey", it is losing its absorbing properties and reflecting more of each wavelength. 

Conversely, a white surface is one that reflects all visible light wavelengths equally well. If white fabric is washed with a red towel, and turns pink, it means that that the fabric has lost its ability to reflect all wavelengths equally, and that the red wavelengths are reflected more than the blue or green ones.

Infrared is not a visible wavelength. It's a longer wavelength than what the human retina can normally detect. Just because we can't see IR, doesn't mean that it doesn't get reflected and absorbed like other light. It works very much like visible light when it comes to absorbtion and reflection.

Dark black isn't necessarily the best  IR absorber. It has to do with the nature of the fabric, too.

I have a charcoal grey chamois shirt that absorbs a lot of IR. It absorbs more IR than a much blacker tightly woven linen shirt.

You might ask how I know that, but you also might be sorry you did. The practical experiments  involve certain public plumbing fixtures, and the IR detection they use to "arm" themselves for action upon your departure. Nuff said.

ScottE -- Member (always) & Moderator (when needed)

As I stated, the material the surface is made from can play a more important role than the color variation.

Try different materials in your tests, and post the resuls.

Black felt. Black fleece. Black cotton. Black leather. Black plastic.

If you had night vision goggles or a camcorder that relied on infrared rather than light amplification, then you might be able to directly observe how IR reflective the different materials are. 

Alternatively, in other threads we've shown that a digital camera or camcorder is usually sensitive to the IR signals. They look like visible lights to the CCD recording the scene. You might be able to use a remote as an IR flashlight, and use a camera torecord how much of it reflects off of different surfaces. 

ScottE -- Member (always) & Moderator (when needed)

Its not so much that we don't see true colour as it is that the brain plays tricks on us.

A and B are the same colour, because of the lighter and darker boxes around them, and that B is in "shadow", our brain perceives B as lighter. I find that if I stare at A for a few seconds without moving my eyes B appears to change colour (at least till my eyes move).

RoboGuide - Your guide to hacking all things WowWee

Welcome to the community, Tinkerer. Excellent screen name. It sums up what a lot of the community members enjoy about these robots.

I'm having just a wee bit of trouble decoding some of the content in your reply, but picked out a couple of things I thought I could comment on.

I don't think you refer to vision as subtractive or additive. That's for how we characterize how frequencies add or subtract before they reach the light sensors. The sensors, whether biological or technological, are sensitive to a range of frequencies. I guess by that logic the model is one of frequency absorbtion by the sensors, which is the basis for subtractive color mixing.

If you don't have multiple sensors that are sensitive to different frequency ranges, then you don't see any different colors. Following that logic, we don't add or subtract frequencies so much as we detect relative amounts of different frequencies. Our brain is doing some frequency mixing to provide a tally of

Our human color perception certainly varies from person to person, and can change within a single person based on medications or illness. I'm sure we're all aware of people who are color blind. They cannot differentiate between some groups of frequencies. Lots of background information on the mechanisms and extent of color perception deficiencies is available on the site listed below.

http://colorvisiontesting.com/ 

I've often pondered whether we really see anything the same as somebody else does. We're not born with the word "blue" being linked to a given neural input. As children we are taught to recognize and use labels for colors based on somebody else's perception of them.  

"What color is this?  This is red. Can you find something else red? No, that's not red, that's green."

That little scenario doesn't play out too well for children with the inability to differentiate between red and green. 

Our poor RSV2 has the crudest level of color detection. It can tell when something is mostly green, or mostly red. (the bowling pins and bowling ball) It's easily confused by the spectrum of the visible light used to shine on the objects.  Flourescent light versus incandescent light versus sunlight can confuse the color detection. It tries to detect a blend of colors we associate with skin. A manilla folder is just as likely to be detected as "human" as a flesh and blood person is. 

ScottE -- Member (always) & Moderator (when needed)

How do you do Mr. The Tinkerer, sorry I didn't get a welcome message to you I'll try today!!(:^))

"Life is not measured by the breaths we take, but by the moments that take our breath away."

so animated gifs wont upload?

I,robot114 said: How do you do Mr. The Tinkerer, sorry I didn't get a welcome message to you I'll try today!!(:^))

Ok thankyou :) and its nice to meet you, im looking forwards to a very long stay with the robocommunity its a lifelong passion of mine robotics and the likes.

Im a I.T Professional by trade but yes robotics is really what i like the most computers just play a vital role for me :)

Good day ladies and gentlemen(PC and all that . . . . )
Regarding RSV2, i have a specimen that's as blind as a bat(yes i know bats have and incredible sensory perception that runs rings round our own, but it expresses my point). You are ALL obviously a lot more clued up on all these matters than i, so can anyone suggest a good solution to my dilemma?

i've tried all of the vision settings, but so far i've had RSV2's recognition of the green ball once, that of the red skittle and once that of my hand once and all at the expense of my time nursing and educating the brat with little success and as for seeing a skittle then following it with the vision sensors and proceeding to perform a strike with the ball, i can honestly say, "it'll never happen!"

i've tried increasing the ambient light to the extent that only the floodlighting on a football pitch would be an improvement and this after adding a light source two each shoulder and a back pack to power them.

Maybe i just got a dud, but if there are any remedies or hacks that can be explained in laymans terms i would really appreciate your help.

Tinker. is that swap from rgb to cmyk something i missed in the manual? Must be a hack right?

You think you've got problems?

Thanx for the info Nocturnal, it's a nice neat little mod and if it works for my RSV2 it'll be a real nice touch. Looks good too!

You think you've got problems?