For more than 100 years, photography has basically been the same. Capture light and shadows to create an image. Its all about the light.
In the past it was on film, now it is with digital sensors, but the main idea is still the same. You can't take a photograph without light (although there are some cameras that really don't need much). It didn't matter if the images were black and white or colour. Modern sensors are truly amazing but the principles have always remained the same.
No matter when the image was taken, the fundamentals are the same: you record light.
No light = no photo.
The thing is, too much light, like on a bright sunny day can cause havoc on your images. Mostly because while your eyes can see in both the bright area and the dark shadows (a dynamic range of about 22 stops), the best digital cameras only do about 12 -14 stops. What does this mean in practical terms. If you try to take a photo on a bright day of a plant on a window sill, you will have problems. If you look outside the window you can see the trees and the foliage. If you look at the plant you can see the flower. You can see both effectively at the same time. But your camera can't. You either see the flower with the window all white or you see the outside world and a dark shadow where the flower is supposed to be. Older photos, especially older black and white photos had even poorer dynamic range.
There are two principles regarding light: quantity of light and quality of light. You need enough light to take a photograph but light itself comes in many flavours. Light is measured in degrees Kelvin and is a mix of colours. Everyone assumes white light is always the same but that is not true. It is a mixture. A warm sunset has more yellows and reds whereas a fluorescent light is very cool and will often make images turn green. Anyone who has gone snorkelling, will tell you that there are lots of colours of light missing particularly the deeper you go. Understanding quality of light will allow you to get better images for the same shots.
Knowing how to see light and thinking about how it will affect your images is what differentiates a good photographer from a great one