Weird color shift on laser projection

[gi-jones]

Hi

I don't think this is strictly speaking a DCP-o-matic problem, but I'm not sure where else to ask.

I have created a DCP of our first feature film. J2C export from Resolve, DCP done in DOM.

When testing in the cinema we have found that the main screen shows a weird color shift - very visible in scenes with a lot of blue colors. It seems as though the colors are pushed toward purple. Most of the film looks fine though, but some scenes suffer a lot.

Now the weird thing is, that we also tested on a smaller screen in the same cineplex. On that it looks perfect - completely matching my calibrated monitor at home.

The main difference is that the big screen runs on a laser projector (Barco I think). They also have a different playback system. The tech guy at the cinema says this is due to some kind of perception issue with laser projectors, but I feel the tint is way too heavy to be explained by that.

Are we talking a calibration issue on the part of the cinema? Or is there something I'm not considering?

[Carsten]

Quite a few people think that laser projection is difficult to calibrate for a broader audience's perception. Note there are different types of laser projectors with different types of laser light sources. Some are more prone to color ambiguities than others. You are right, though, that, properly calibrated, the differences should be so small that they should not be noted at least by a general audience. Do you have a chance to watch other content on both projectors, e.g. a common trailer?

[gi-jones]

Hi Carsten

In the meatime I actually did exactly that. Went back to the cinema and watched my own DCP on both screens again - and watched a trailer for "Asteroid City" on both screens.
I'm pretty sure there was also a noticable difference in the trailer, so there's probably some calibration issue going on. But is was way more clear with my own film, so I'm worried that I might have done something un-kosher in the grading.

I'm looking into the Gamut Limiter in Resolve right now, considering if I might have some color values popping outside of the allowed spectrum or something. Does that sound like the right tree to be barking at?