A Nebula in true color
Many of the pictures of nebula you see, including from Hubble are taken using narrowband filters. This means they capture a very narrow spectrum of light, and are assigned to color channels in order to clearly show the formation and general material composition for scientific purposes. The "Hubble" palette for example, is accomplished by gathering light with a Hydrogen-alpha filter, a Sulpher-II filter and an Oxygen-III filter.
But what would this amazing nebula look like if you traveled there with a spacecraft? Or had amazingly sensitive vision with a huge telescope?
By simply capturing light with an RGB camera, or using Red, Green and Blue filter we can find out.
For the Pelican nebula, a target rich with Hydrogen, the image would be predominantly red, since that is the wavelength it emits when ionized by a nearby star.
This is what you'd see:
Now you can see why astronomers gather data in narrowband filters. It tells us much more of the story.