Fake a Black Background: Introducing the Inverse Square Law

This is guest post from a couple of years ago that I'm moving over from the old blog, so if you are are a long-time follower you may have this before but it was such a good tutorial I had to share it again!  If you have ever wondered how you can get a black background without a backdrop (or just need reminding!), then this is the post for you. Over to my good friend and wonderful photographer, Jan, to share how this is done....

Photography Tutorial: how to easily fake a black background using the inverse square law.

First of all, thank you Audrey for having me back.  Don’t you all just love Audrey’s blog?  I think she can explain things more precisely than anyone else out there.  She’s amazing! 

Black background.  How on earth do photographers get that cool black background effect?  I’m going to attempt to show you how to achieve this neat effect in an easy to understand and implement kind of way.  If you have further questions, I bet Audrey will be able to answer them for you!

First, let’s look at a pull back.


 You can see that this room could be well lit with the curtains totally open or only slightly lit with the curtains closed.  In order to achieve a black background, it’s best to have a light source that is rather strong (hard light), like light coming in from curtains that are only slightly opened.  Are you following me? 

 Do you see the chair in front of the right curtain?  Let’s pretend that you put your subject in that chair.  Your subject is close to the hard light source.  Without getting into the physics of it too deeply, the closer your subject is to a hard light source, the quicker the light will fall.  When light falls off quickly, you get a black background.  There’s actually a physics term for this, and it’s called The Inverse Square Law.  Check out the video about this on You Tube and it will explain things far better than I can here...

Let’s go back to the subject in the chair.  Do you see how the back wall is a decent distance from the chair?  You’ll get the best effect if you do the following:

  place your subject close to a hard light source

  make sure that your background is darker and a decent distance away

 Do you see how the light falls off quickly and the back wall is a decent distance from the chair?

Let’s put this in practice.  My daughter recently got her haircut, and I wanted to tell the story of her haircut without any background distractions.  Black background!  She stood exactly where the chair is and here’s what I captured SOOC.

 And here’s the edited version....

Clear as mud?  Go ahead and give it a try!  It’s really a fun way to play with the light and tell your story in a different way. 

Thanks so much for taking time out to share your knowledge with us today Jan!