Project an image onto entire wall?
December 2, 2012 3:47 PM   Subscribe

Is it possible to use a projector to project an image onto a wall that will span the entire wall, that is, do all / any projectors allow to stretch an image to arbitrary angle since the size of the room is limited? I would like to sketch an image onto an entire wall using this method. I don't think there is any way to actually print an image onto a wall using some kind of a setup with an inkjet head moving up and down along the wall... were there any experimental rigs that can do that?
posted by rainy to Technology (17 answers total)
Sounds like custom printed latex wallpaper will do what you describe cheaply and easily.
posted by cromagnon at 3:55 PM on December 2, 2012

How big is the wall? How far away from it can you get with your projector? My concern would be that the edges would be distorted, or that the bulb in the projector wouldn't be strong enough to make a clear image.

Have you considered projecting multiple smaller images with enough overlap to allow you to line up your sketch? Sort of like taking a panoramic photo.
posted by cabingirl at 3:58 PM on December 2, 2012

Overhead projector wall art?
posted by JujuB at 4:00 PM on December 2, 2012

Response by poster: Thanks for the answers so far!

cromagnon: I think actually painting on the wall would look much better, especially when standing close to the wall

cabingirl: there is no wall - I would want to do it when I find a new apt and move in; potentially I would want to do this on many walls, perhaps all! That's why I'm thinking over the possibility of a somewhat automated approach...

JujuB: I would like it to be painted so that it looks great in all light conditions.
posted by rainy at 4:32 PM on December 2, 2012

Response by poster: Incidentally: is there any chance, in the near future, that e-ink prices on large screens will come down enough it'll be practical to use one for an (almost?) entire wall, even if a small one? That would be pretty awesome, especially if it's colour e-ink.
posted by rainy at 4:34 PM on December 2, 2012

Personally, for walls too large to get in a single projection, I would divide my art up into sections, then project/trace them one section at a time. An opaque projector is the tool of choice.
posted by Thorzdad at 4:41 PM on December 2, 2012

You may be looking for the Rasterbator
posted by grateful at 5:36 PM on December 2, 2012 [1 favorite]

Response by poster: Rasterbator is not quite what I'm looking for: I suspect it doesn't look as good in the room as in photos (I had posters printed out on very large sheets of drafting paper and it's still not nearly as nice as if it were painted..)
posted by rainy at 6:12 PM on December 2, 2012

Response by poster: To be fair rasterbator is very neat and I'm glad I've found out about it; I may use it in a hallway or someplace like that.
posted by rainy at 6:13 PM on December 2, 2012

Many projectors do "keystone correction" which is I think what you're asking about. But probably not for extreme angles. Maybe you could do the correction in an image editor first?
posted by hattifattener at 6:56 PM on December 2, 2012 [1 favorite]

Best answer: I'm sure I've seen software for extreme keystone correction- I think for projector graffiti, but I can't find it now.

Basically, the idea is that you warp the image before it's projected, reversing the perspective transformation that the projection produces. You will lose resolution towards one end of the image, but if you're tracing it anyway then it might not be a problem.

You can experiment with this manually: the GIMP (and probably Photoshop too) has a Perspective Transform tool. You could load the image up on a laptop, sit parallel to the surface, and project your desktop + the GIMP fullscreened onto the wall, and keep warping until it looks right.
posted by BungaDunga at 7:16 PM on December 2, 2012

Response by poster: That's great! But which projectors are well suited for this application, what should I be looking for? I know 0 (zero) about projectors.
posted by rainy at 7:25 PM on December 2, 2012

Best answer: Epson's throw distance calculator should give you some idea.
posted by flabdablet at 8:03 PM on December 2, 2012

Response by poster: flabdablet: thanks, this is really great.
posted by rainy at 8:17 PM on December 2, 2012

Best answer: We used simple overhead projectors -- the old school ones that took transparent sheets, rather than digital projectors -- to draw theater sets on large frames when I was in school, using multiple sheets of film to hold the entire image and just moving the projectors and re-lining it all up each time.

You keep the projector the same distance from the wall ( a line taped on the floor with painters tape will help with this ) and don't mess with the focus, just move the projector up and down (higher and lower tables) and side to side as necessary.

And this was grade school, so if a bunch of minimally supervised 11-year-olds could manage it, how hard can it possibly have been?
posted by jacquilynne at 9:11 PM on December 2, 2012

Best answer: Pretty much any projector that is not at the very bottom end will do keystone correction. The main issue you are going to have is the size, since it is uncommon to project onto a very large surface from a relatively short distance. If you can get your projector 30-40 feet away than you shouldn't have a problem, but that isn't likely indoors, so you'll have to pay special attention to finding one that has a wide lens on it. Look for projectors that advertize being able to be placed very close to the screen.

This is assuming you're talking about computer projectors, and not an overhead transparency projector.

I'm assuming you're looking to project an image and then paint over that image onto the wall, correct? Do you have painting experience, or are you going to hire someone to do this? This might change how you want to approach doing this.

My suggestion would be to contact a few AV companies in your area and describe what you want to do. They can rent you a projector for much less money than it will cost to buy one, and they should be able to help you select one that will work for what you want to do. You may even want to have them come and set it up for you, making sure to mention that it is important that the image is correctly adjusted for keystone and proportion. Making these adjustments is very easy for someone who knows how to do it. Many places will only charge for 1 day rental if you do it over the weekend, so ask about this, and you may be able to pick it up Friday afternoon and drop it off Monday morning.

You'll likely want to have an image of a big square grid to use to calibrate things, since your concern here will not only be that the vertical and horizontal lines are straight, but that nothing is being stretched too far in either direction.

As to the quality of the result, I honestly think that vinyl wallpaper will likely look better unless this is painted by someone who has some experience painting large surfaces, or you are doing a very simple design on the wall. However, if you're the type of person who loves art projects like this, than go for it! The worst that can happen is that it doesn't turn out too well, and you repaint the wall afterwards.
posted by markblasco at 9:17 PM on December 2, 2012

Response by poster: markblasco: thanks, this is really helpful! I'll definitely want to talk to AV companies, and I don't mind experimenting with different types of paints, brushes, etc, and starting over if needed.
posted by rainy at 6:49 AM on December 3, 2012

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