No Light no photography
I think that makes it the most important part of photography. But maybe that is just me.
First of all, there is no white color. It also follows that there is no black color. Let us start with black. It is simply the absence of light. White is basically a lot of light (of different colors) mixed together. How exactly this mixture has to be is a difficult topic see white balance. Color comes when we see a different mixture of light color components. And if we do not have the white fixed, the mixture can also be skewed.
The second fun thing is, most colors we see is what objects reflect to us. Basically if we see a red object, it absorbs everything but red. But if the object is luminous (it produces light), it is the opposite. A red LED light is really only emitting red light.
- Using flash
Light is a bit complicated. From the scene you photograph until you see it on a media the following steps all have an influence
The light source is not always identical, it has many characteristics. It can be warmer, colder it can be sharp or diffuse it may have a different color..
The environment can alter the light as it travels from the source, fog, mist, smog, reflections from different colored surfaces, movement, light seeping through different fabrics, all contribute to the properties of the light that arrives on your lens
Lenses and filters on the optical path do not always react to all the spectrum the same way (ideally they should, but is not always the same)
The camera captures light intensity, it can not distinguish between colors, so there are filters on top of the pixels that let through only part of the light spectrum through. So one pixel only sees red, the other one green and the other blue for example. This filtering and how the different filters are organized on the sensor has some effect
The camera electronics convert the light intensity into an image. Almost invariably there is some processing involved here. Every pixel of the image usually gets three color components, although physically individual pixels only get parts of the light. One of the big philosophical debates in Internet Photography forums also is part of this story: JPEG vs RAW related how the image is stored and how much of the pure information that was captured gets lost in the process of storing what the sensor has captured in the JPEG format. But regardless of the format, basically all cameras have some amount of tuning. If you think about it exposure, aperture and ISO play with the light intensity that the sensor sees. There are other subtle parameters, correction factors, and choices being added. The white balance and various color modes are some of these.
Once the image leaves your camera there could be more processing, some to fix issues, some to enhance the image and some to prepare the image for the media it will be used to display it. This can be scaling adjusting to a different color profile (printers use Cyan, Magenta, Yellow colors rather than Red, Green and Blue that is common for digital cameras)
And the media, your screen that displays it, the paper where it is printed will have different characteristics. More over they will be viewed maybe under a different light, and over time (especially for prints) the colors will degrade maybe not at the same level.
The last piece of the puzzle is the human processing of the image. There are physiological factors here (eyesight, various eye defects), as well how brain interprets the biological inputs. There are many optical illusions (see the site of Michael Bach), or the fact that your brain manages to remove your nose from your vision can show you how much actually your brain contributes to what you experience.
These pages are for Amateur Photographers and not really for seasoned photographers and professionals. I have no affiliation or commercial interest with any brand/make. I write from my own experience. I ended up using mainly Nikon, so I am more familiar with this brand than others. See price for notes on pricing as well as photography related links.