gmartin4 Loc: Puerto Rico

How is Color Perceived?

Objects in nature derive their color from colorants they possess that absorb or subtract certain wavelengths of light while reflecting other wavelengths back to the viewer. For example, a red apple really has no color; it merely reflects the wavelengths of white light that cause us to see red and absorbs most of the other wavelengths. The viewer (or detector) can be the human eye, film in a camera or a light sensing instrument. The human eye contains two basic types of light receptors: rods and cones. The rods are sensitive only to the presence of light, not color. The cones are sensitive to color. During normal daytime vision, it is the cones, not the rods, that actively contribute to vision. At night, the more sensitive rods take over and give us night vision. There are three groups of cones, each sensitive to a portion of the visible color spectrum - red light,
green light and blue light. The brain receives signals from the cones, processes them, then evokes the sensation of color. Various combinations of light waves evoke the sensation of other colors. Color perception varies from person to person. Perception is a subjective phenomenon influenced by many variables including the light source, surrounding colors, mood of the viewer and individual variations in
our visual systems. A small number of people have color-deficient vision. The most common form is the inability to distinguish between reds and greens. These
people are considered color blind. This phenomenon may result from one type of cone missing or a defect that affects analysis in the brain. Color blindness affects
about 8% of men and less than 0.5% of women.

Stay tunned for the next chapter : How is Color Reproduced?

Thomas902 Loc: Washington DC

gmartin4 what is your intent here? You BIO states your Occupation: Computer Technician... The post above is at less than a high school level of medical knowledge... Possibly staying in your occupational field by offering a dissertation on the various color spaces i.e. Adobe RGB, SRGB CMYK etc. and their application to photography which is likely more in line with what UHH members need to get their head around...

That said if you have a thirst for knowledge on the anatomy and physiology of human vision I would strongly recommend investing 20 or more hours studying the Kahn Academy's elegant lectures on the aforementioned. I'm currently tutoring a nursing student studying to take her NCLEX-RN exam and we both agree that Kahn Academy's presentations are likely the very best currently available...
https://www.khanacademy.org/science/health-and-medicine/nervous-system-and-sensory-infor#sight-2014-03-27T18:45:34.237Z

Until you have a firm and comfortable knowledge-base on anatomy and physiology possibly standing down until you have achieved same would be germane to any mission on teaching the aforementioned without professional credentials... Enough said...

I wish you well on your journey gmartin4...

MichaelH Loc: NorCal via Lansing, MI

Thomas902 - thank you for the link to the Khan Academy. I knew they had classes on coding and other tech info, but biology - very cool!

gmartin4 Loc: Puerto Rico

Dear Thomas902, Thanks for the link. And yes, I'm a computer technician that repair the large format Inkject printers from 17 to 64 inchs wide. I had severals training in the Ink jet industry that I like to share with the brother's in photography. My data could be unrelevant for many of you here, but I have faith that photography is not only for "baby boomers", like you and me (I'm 59). I understand that UHH does not reject 15 year old rookie that wants to be part of our forum, and those brothers appreciate the knowledge I'm introducing. Just keep reading and finally you will se what I'm traying to explain.

MichaelH Loc: NorCal via Lansing, MI

MY experience watching 15 year olds with technology is they quickly and seemingly randomly press/click buttons until they get the result they want (or some other result that distracts them from the original intent). I am always surprised when they get to a satisfying result, but they seem to. Perhaps the 15 year olds I have come in contact with have low expectations. OMG - I sound like my dad! Ouch!

Doyle Thomas Loc: Vancouver Washington ~ USA

Fotoartist Loc: Detroit, Michigan

I don't see how your information on color is acutely important to photographers. Photographers need to know the difference between Adobe RGB, sRGB, and Pro Photo color spaces. Photographers also need to know the color wheel to this degree: Color in the digital world is Additive. In other words, if a picture is too blue, you have to ADD yellow to neutralize it. If too red, you ADD cyan. If too green you add magenta. This helps with white balance and in post processing. Beyond that, let's not complicate it.

lenben Loc: Seattle

You state that color deficiency (we in the profession avoid the term "blind") is due to a missing cone. In fact the common sorts of color deficiency have the same number of cones as "normals" do. Thus their acuity is normal. Their problem is that the spectrum of visual pigment is shifted: sometimes modestly so they are weakly deficient, and sometimes matching one of the other cones so they are fully deficient.

aellman Loc: Boston MA

I agree with other members that this information is of little interest to most (not all) photographers.
It begs the question, "Did someone ask for this?"

Doyle Thomas Loc: Vancouver Washington ~ USA

"I don't see how your information on color is acutely important to photographers."
Photographers need to know how colors "feel" the better you understand what you are looking for
the more you will find.

http://www.primaryfocusphoto.com/why-color/

Kiiski Loc: Chehalis WA

Wasn't relevant to me, but, He isn't hurting anything, it's kind of like television, you don't like it, move on.

Doyle Thomas Loc: Vancouver Washington ~ USA

"Wasn't relevant to me"

Everything you do, see, feel, and learn should be relevant to your Photography, you just need to figure out how.

Just because it does not speak to you does not mean it does not speak.

Brasspounder001 Loc: Erewhon

Those are excellent tutorials on various biological subjects.

aellman Loc: Boston MA

True.

gmartin4 Loc: Puerto Rico

Thank you all for your comments. More that 800 people, most of them members, had seen this topic. On of those is a partially color-blind fellow member. He left me a very positive private message that empower me to continue posting articles that could be unrelevant for the mayority, but if the info help just one member, that is enough for me.