Photos of Space Are Actually Black And White. Here’s How They’re Colored
The photos of space you see go through a complicated but important process from grayscale to their vivid coloration.
Take a look at the picture above. What do you see? Do you recognize anything? Well, you can tell that this is a picture of space, most likely by a telescope. This is one of NASA’s most iconic photos of space, though you probably haven’t seen this picture before. Why do I know this? That’s easy. It’s in black and white.
You might not know this, but almost every photo of space starts out this way. Additionally, most telescopes only take black-and-white pictures, the most prominent of which probably being the Hubble Telescope.
Now, look at the colored picture. It’s mostly the same thing as the one before, but you’re more likely to recognize this iconic space photo. It’s called the Pillars of Creation, a photograph of the Eagle Nebula 6,500 light-years away by the Hubble Telescope, and it’s a prime example of the coloration process of space pictures.
So, what is this process, and what can it do other than just add color to photos of space? Let’s dive into it.
How Does This Process Work?
Before we look into how space photos are colored, we need to understand how light works in the universe and how we perceive it. Shown above is the spectrum of all frequencies of light in the universe that we know of, ranging from radio waves to gamma rays. However, we can only see and comprehend a fraction of this spectrum, labeled “visible light” in the diagram above, as most frequencies of light are invisible to the human eye. The light we can see, though, ranges from red at its lowest frequencies to violet at its highest. We can see this light because of cells called cones at the backs of our eyes that interpret the colors of objects by the light reflected off them.
We have three types of these color-sensitive cones in our retinas, each detecting different ranges of light. Additionally, each of the cones picks up long, medium, or short waves of light. This roughly corresponded to three colors — red, green, and blue, respectively.
Thus, these are known as the primary colors of light, and they are the basis for all the wavelengths of light we see. You’ve probably heard of the RGB model, in which red, blue, and green light are added together in certain amounts to create a broad range of colors as a result. This model is commonly used in displays for electronics and is a crucial part of understanding how space photos are colored from their original black and white stage.
Now that we understand how light works, let’s dive into the process.
The pictures of space that you normally see are most likely from Hubble, so we will use Hubble as our camera example. First, the telescope needs to be focused properly, as the subjects of the telescope are usually very far away, so the right measures need to be taken for the telescope to get a good picture.
Then, the camera starts taking the picture. The light that the telescope sees is filtered into long, medium, or short wavelengths. This results in three different pictures picking up light for each range. However, this process takes time. Each frame takes a certain amount of time to actually take (some say 1,000 seconds).
Additionally, since Hubble is orbiting the Earth constantly at 17,000 mph, it will most likely take Hubble multiple orbits to be able to take all the needed frames. After each photo for each range of wavelengths is taken, though, each of those ranges is assigned a color based on its location on the color spectrum, most likely red, green, or blue (RGB model!). This is called broadband filtering, as light reaching the camera is filtered into wide ranges of long, medium, and short.
Later, the multiple frames picking different light wavelengths are compiled into one using programs like Photoshop. After some touch-ups, the photo is complete, and you’ll end up with images like the one above.
What Else Can This Process Do?
While seeing space in color is simply an amazing experience, there are also other scientific uses for the process.
For example, scientists can use broadband filtering and something called narrow band filtering to detect gases and their presence in the universe. If scientists were examining the remnants of a supernova, they could find out what gases were present or were expelled after the explosion. Since all gases absorb different wavelengths of light, the colors assigned to these during the photo coloration process are important.
Seeing how common gases appear on the spectrum can give astronomers more of an idea of the distribution of gases in our universe, possibly giving evidence of extraterrestrial life or other galaxies and systems.
What Does This Mean for the Future?
Our universe is a vast abyss full of things that humankind will never witness or experience. We’ve only explored about 5% of our Earth’s oceans, let alone space, but we will keep marching forward. While we can only think about how the universe looks through this coloration process, it won’t be long before we can take our own colored photos of space, clear as day. In the meantime, this broadband filtering process could help humankind in so many ways — from finding habitable planets for humans to exploring more of our enormous galaxy.
We are challenging boundaries, innovating, and breaking barriers every day. Innovation isn’t and won’t stop, as there will always be a strive to solve the world’s problems, and I am excited to see this in action in the future.
As Steven Jeffes said,
“Innovation is the unrelenting drive to break the status quo and develop anew where few have dared to go.“
