Build Your Own SLA/SLS

I'll be posting a guide soon that shows how to properly create a mask, but overall, it looks like the technique you're using should work. The important part is that it's an inverted multiply mask.

I also had very little success.
I photographed the projected image brightness, Made a mask in Photoshop and tuned the hell out of it. After making the mask I set up a print of a box that covered all the surface and re-photographed the projection to make sure it was the same brightness.
Due to the nature of dlp light I had to use very long exposure to get a proper reading in the camera.
Even after the light seemed to be uniform with the mask, in actual print there were still margin areas that were underexposed. So the only solution for now is to add pigment until light bleeding is no longer an issue and to overexpose so that the corner areas are ok.

I was wondering if it would be a solution to add a diffusion screen to the light source as the pattern of light does not seem to be due to optics and vignetting but more from the point nature of the light source.

maybe henry locke ( user HTL )could help us with the mask. exact words from a post in january:
" I did use the mask feature and it worked perfectly with my brightness correction mask. "

helppppppp !

Hello

I made a mask but, could you help me about which file format i have to save?
Is PNG ok?

Projector Light

Mask

Masked Light (Multiplied at Photoshop)

ProjectorLinearBurnMask.png (6.32 KiB) Viewed 20158 times

Best Regards
Cihan Alak

That looks about right, it should be in png format as a multiply mask.

hi cihanalak,

im lost getting a correct mask. can you describe the exact steps to get your second image?

i load a photo taken from the projected image ( your first posted image ), but i dont now how to proceed to next step.

everybody say mutliply in photoshop, but when i try to create a new multiply layer, nothing happen ...

this is a photo taken from my projector.

if i duplicate layer and apply multiply , i only get a image a bit darker than original. clearly im doing something wrong ...

Guys, don't forget there is always vignetting from the camera lens. So you should also make a mask for the photograph or use a SLR with a lens that lightroom can correctly correct