This was my first attempt at making a gif asteroid



After reaching this point the next step was to clear the area around each individual asteroid image to allow a background image (below) to show through.



When attempting this I soon realised I’d made a big mistake, I’d shot the rock against a black background. I know now I should have used a coloured background to make the extractions easier, ah well live and learn, I won’t make that mistake again.

I like to use this color for backgrounds or none at all.

Yes, I can see now, I googled green screen and looked at a couple of articles on gimpchat. I'd shot the rock in the dark with one bright light source to get high contrast images, I’ll try again with a brightly lit green backdrop

You photographed this? On a turntable?

-Rob A>

Why steve? It looks great the way it is.

In reality, the asteroid masks and unmasks stars in the background when it rotates. To do so you have to have to make the background of the frames transparent, which is a lot easier to do if the background is of a color not found on the asteroid.

But this is going to be a very challenging photoshoot because you need a uniformly lit BG that doesn't create extra lighting on the asteroid itself, and you don't want the asteroid to create a shadow on the BG either.

To Steve: possible cop out: if you are turning the asteroid by hand between shots: take two pictures each time: one like you do right now, and one with the asteroid lit from the back against a white BG, and then use the negative of that second shot as a layer mask for the first.

I took 162 photos but not on a turntable as such, the set up was as in the photo below, the tin being turned a marked amount by hand between each shot. The paper was taped to the stool and the tin kept inside a circle which had been drawn around its base.

Thanks Sally, its fine as far as it goes but falls short of what I was aiming for.

I see what you mean with the problem of the asteroid shadow (seen on the photo 2 posts back), will try some single trial and error shots to see what works best, perhaps putting some distance between rock and background/green screen and place the lights behind the rock to light the screen.


Thanks, a good idea, will keep in mind for future projects. With 162 photos taken in this sequence I’m not sure I’d have the will to double each shot.

Awesome

It's fantastic your result Steve. Well done!

@Steve
Well, yes. The trail back to the drawing board is a pretty well worn one. Still, the effort is pretty convincing one. It was a couple of minutes for me before light dawned over Marblehead that this wasn't NASA footage.

Great Gatsby demo VFX reel

You might take an interest in this demo reel put out by Chris Godfrey a year or so ago. He was the Visual Effects Supervisor on the film The Great Gatsby. You get to see a lot of cuts between scenes as they appeared in the film and how they looked like on the lot, with the green and blue screen rigs positioned behind the action shots. It's kind of eerie to see a car that was barreling along in Australia in 2012 transpose itself into a run across the 59th Street Bridge in 1925, with the New York City skyline of that era spot on. Probably, you won't have to do anything that ambitious.

Garry

Thank you gbarkovalev , Issabella and Garry

And thanks for the link Great Gatsby demo VFX reel Garry, a fascinating and insightful demo