Using a Projector

I am really interested in using a projector for some upcoming studio sessions. I am looking to come up with images like these:
http://www.boredpanda.​com …photography-dani-olivier/

One thing I am struggling with is keeping the background black. So far the only idea I have is angling the projector in such a way that the projected image doesn't hit the background. I am thinking the projector would need to be either above the model angled down so the "excess" light hits the floor or off to the side maybe at 45 degrees to the background so the extra light goes past the background. I do notice that the majority of the projected images I see aren't full length suggesting that the excess light is probably hitting the floor. Any other thoughts? Also I am assuming that I am still going to pick up some ambient on the background due to the slower shutter speeds and slightly higher ISO necessary to capture the projector light. I suppose that could be pushed back to black in post.

I have searched the web repeatedly but can't find any useful tutorials on this technique. Obviously I will set up and do a few test runs ahead of time but in the meanwhile I was hoping a forum member may have experience and be willing to chime in.

Thanks in advance!

Have a look into the "Inverse Square Law"

the further back you can get your background, the darker it will be (if it is only lit by the projector)
as an example, if your light source is 1m from your subject, then anything 2m from the source will be two stops darker, and at 4m it will be 4 stops darker - at that point it will likely have next to no effect on the background, especially if you are using a black background

Using flags to cut the spill light will also help

I had thought of that as well. I just wasn't sure I could get the projector far enough back. Definitely something I will experiment with.

Use the projectors offset to shoot the light out of the scene. If you look at the light in your link you can see it was done that way there. The light is coming form the side.

That is what I did here http://jimburns.org/p4​17625595

That is what I had been thinking. Thanks Jim!

I am excited to try it out. Obviously patterns are everywhere on the web but is there somewhere in particular I should be looking?

Thanks again

Just make sure you have the right to use the images. I used a lot of my own.

I liked using a white background better, you can see that in link above. Try that too.

I will. Thanks!

I will definitely make sure I have the rights to use the images. I was ignorant to image rights until I started getting into photography. Now I am very sensitive to it.

Just curious - do you know off hand how many Lumens your projector is? I have a 2800 Lumens Epson and I am wondering if it will be bright enough. I won't have a chance to experiment until this weekend.

The unit I used was 10,000 lumens.

2,800 is ok if your camera has good ISO capabilities. With a projector good contrast means a nice low back level. DLP is better for this but in a single chip unit the color wheel may give you fits depending on your shutter speed.

Don't be afraid to push clarity in LR. It will help a lot with the look of the projected image.

Use a tripod and have the model hold still, take a lot of pics you will end up with plenty of keepers.

Thanks. 10,000 lumens is a bit out of my price range

I will try the 2800 and if not then step it up to the 5000.

I didn't follow your comment about single chip color wheel - if you care to elaborate I always love learning!

here you go, it's and old presentation but the basics are there https://www.slideshare​.net …d-its-future-applications

Awesome, thank you! That is pretty amazing - all those tiny mirrors!! So I assume the shutter issue could be catching the projector "mid color" and creating weird artifacts?

Yes you will end up with only two of the colors and not three or 5 and not six or 4 or...... You need to hit 1/60 nearly perfectly or it will have the wrong color.

Ok. Thanks

Any work around or just struggle with shutter speed?

It won't be too bad. If you have a crop you might want to be carful of noise.

Post them up so we can see them!

Will do. Shoot is scheduled for the 21st. A model who is traveling in from NY. No piercings - no tattoos, tons of experience so should be perfect for what I am looking to do!