Blending problem softedge


i work on a basic multi screen setup:
boygroup, video playback + homography image adjustment, softedge, 5 pc`s,
8 projectors.

everthing works fine, except the blending are of the softedge.
you can recognize the softedge are, it`s brighter than the rest.

we play around with the gamma pin, all dynamic contrast and color settings of
the projectors are disable, the lamp durration is the same …

our assumption is, that the gamme line of the projector (Nec UM330X) is not linear, has anyone a good idea …

thanks in advance


Well, the trick I discovered was you need at least 15% overlap, the more the better to get a better blend. That is a lot of image info you are going to lose.

From my experience this is a limit both on the projector and on the plugin.

First of all the better the contrast ratio of the projectors the better the result of the blend as there will be less “sum” light, so to say… in an hypothetical “perfect projector” where black is completely black you would have a perfect blend, that is not the case in this universe …

Right now you can either set a gamma which is good for plain white/much light or one which is good for darker colors.

On the plugin side it would be nice to have a “per pixel” edge blend fx that will calculate the necessary gamma value for each overlapped pixel, let s say a dynamic gamma calculator.

Anyway What westbam says applies, the wider the soft edge the better the result, although I think that it doesn t really improve the effects, it just tricks the eye.

Disclaimer: this is all empiric assumption and no animals have been harmed

thanks for your assessment

but at the moment the blending problem is more intense than the
usual “low light problem (projector can`t display a real black)”
please take a look on the attached images.

I think that the former applies, you can see clearly see in the second picture that the 2 projectors are not color/gamma matching, and the softedge is way too narrow, do it minimum 3 times wider.

Are you sure you have the systems and patches configured properly?

Might help if you could post a grab of each output to the projectors please.


It’s true I haven t noticed before but it actually looks like there is no soft edge at all…

i think you have to check gamma per color with similar picture like that
place it so that your softedge area cross all color

thats a really nice image, dimix

you could also try to do it analog. with some flaps on the projectors…