Help! I have a dim projector


Well in all honesty, the projector just isn't the right gear for the space I am currently designing in. It is attempting to throw about twice as far as it is made to do.
I currently have two projectors set up, attempting to get one solid image made from the both of them. This was our attempt at making a punchier image. It's not really working, since they are too far. The images are becoming warped at the edges.
We are currently running our show through Isadora and are mapping the two onto each other the best we can. We have tried using both projectors, and then also just one projector with the "stage" doubled. Neither option is ideal.
I was wondering if there are any tips or tricks on editing my content to help? The techniques we are using are washing the image out, and we are definitely losing the color.


Active Member
What kind of projectors? If they are classroom/office projectors you're gonna have a hard time regardless. But a decent projector like a Christi, Barco, or Panasonic should have the ability to stack and make a solid image.
If they're perfectly aligned and you're still unhappy, there's not a lot you can do. Be sure to set yourself up for success by ...
  • Adjusting the brightness and color with an "actor" in Isadora
  • Putting the most important content high so as to avoid ambient light
  • Work closely with the lighting designer to minimize front light (steeper light, side light, etc will help).

If you're unhappy with the alignment, try a demo of MadMapper. This will allow you to pull in Isadora through Syphon, then send the image out to the two projectors in MadMapper. The idea is that both projectors take the same input, but then you can corner pin / mesh warp the duplicate input onto the same physical space. If all four corners are mapped to the same physical location, then all the pixels in between should also end up in the same physical location (with room for adjustment using the mesh warp feature). This way you can perfectly align two stacked projectors.


CB Mods
Premium Member
Fight Leukemia
Hi. I think we need to get some more information to help you as much as possible. When you say that your projectors are too far, does that mean that you have too large an image and you are trying to fix that? When you mention that the images are becoming warped at the edges, is this due to keystone by being off axis?

Let's see if we can get you started until you can answer that. You are right in that you will get a better image that is brighter by stacking your images (both images occupying the same space). This is best done by having the projectors one above the other and preferably with one or both having lens shift capability. If you are using common home theater or business type projectors, they will not have lens shift. You will want to optically align the images the best possible. To do this, send a grid test pattern to both projectors at the same time. If you can make one grid green and one red to see the colors blend as they match and to help differentiate between the two projectors, that will make your life easier. If you don't have them stacked one on top of the other, you will run into horizontal keystone which can play tricks on you. If you don't have lens shift, then you will end up with a vertical keystone which should be relatively easy to handle.

Using the doubled "projector" actor in Isadora may wash out your image. When I do that, I usually make the second one set at only about 50% intensity. You want to make sure that you have the best contrast possible in your content if you use this trick as you will lose contrast in with the doubled actors.

If you are using Isadora 2.x, then you also have the ability of warping each output to fix your image. If you are using 1.x, then hopefully you are using a Mac to do the above Syphon/MadMapper trick. Ideally you want your content to be as closely optically aligned and do the minimal amount of digital alignment possible for the best image. However, if you do need digital alignment, begin with the center of your image as perfectly aligned as possible with identical zoom.

Also, for lack of "brightness", you have a couple of things to consider. The surface on which you are projecting makes a big difference. If you are not projecting on an actual screen, you won't know things such as gain and viewing angle of the surface. If you don't have a screen, you may need to play around a bit with the coating of the surface (if possible) to help it reflect the light you have a bit better. Your only other course of action is working with the lighting designer. Beyond the lighting angle mentioned, you also want them to lower the overall light level. The human eye is drawn to the brightest source and will adjust to that. If you have the option of reducing the size of your image, that will also allow it to be brighter. Obviously, this might not be possible due to the throw distance you mentioned.

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