Do you have some references please?

Also I'm a bit confused about the statement invisible to the human eye. If it absorbs light then something will still be visible, i.e some darkness. Please specify what you mean, I am very curious :)

A few points to help you succeed in the future and gain good votes.

Make sure your iamges are referenced properly, and the are free use; not copyright. Here is an example:

Image credit:-wikimedia

It's also good to ensure that the images are not protected by copyright and are fair use images or creative commons. I like to take my images from wikimedia, they are usually exactly what i need anyway. I hope that helped.