Wildly Different Colour Balances!

[toast]

Hello all,

I wonder whether any of you have any thoughts about this:

 

I'm working on a show at the moment which uses a wide projection screen at the back of the stage. We've got three projectors and a Catalyst to softedge, and it's back projection.

 

Now the problem I'm having is that there's a huge difference in the colour reproduction of the projectors - not normally too much of a problem but as we're using them together to create one image it's an issue.

 

Now I'm used to having to match images between projectors, but this is by far the worst case I've seen - and despite spending hours using the inbuilt colour correction and gamma settings.

 

There's even a notable difference between the 'video black' that's projected when the units don't have any signal - one's what I would consider a normal dark grey colour, but one is much brighter with a red/blue tinge and the other is brighter still with a greenish tinge.

 

The projectors are Sanyo XP56 5ks, which seem to work fine in every other way. I've checked the lamp hours, and they're all fairly new, and within 100 or so hours of each other.

 

Any thoughts? I've tried pretty much everything I can think of...

 

Thanks in advance!

[Nick S]

There's even a notable difference between the 'video black' that's projected when the units don't have any signal - one's what I would consider a normal dark grey colour, but one is much brighter with a red/blue tinge and the other is brighter still with a greenish tinge.

 

Sounds suspiciously like an LCD issue with your projectors. They're 3 color LCD models, How you deal with it depends on how confident you are with projector maintenance. Potentially, the only way to fix it could be to swap an LCD out (and red/blue tingle suggests a problem with your green LCD, for example) - or, a more feasible solution in the short term, swap out/replace the projector completely. LCD panels do wear out over time, although normally the blue goes first giving a somewhat yellow tint.

[Toxopholist]

Unfortunately the sanyo's don't really have the level of adjustment you need to do an truly good looking edge blend. They are designed as a table top or ceiling mounted projector only ever really expected to be shown on a single screen and the quality contol on the optical side of things isnt good enough to ensure that any two projectors will put out the same whites and blacks and not being designed with side by side comparison in mind, even brand new, they dont have the adustment to do it..

 

I am on a show doing a 3 projector blend with Barco R12s and even then it is a bit of a struggle because we have too cheaper screen material, and that is at £1800 for a 8m screen. We asked for material called opera blue which while cutting 30% of your light output does give a nice even image reducing hot spots nicely. Rear projection always adds an element of complication tring to get an even colour blalnce, it is acheveable, but only with the right projectors, material and lenses...

 

The best you can hope for with those is to put horizontal grey bars up and make sure you have the best contrast and brightness match you can get. Then you have limited adjustment for the colour, but not really enough, you might be able to get your whites to match, but you have no black adjustment at all, so what you have is what you have. You will also find you end up having to grind the projectors down to the level of your worst projector...

 

Unfortunately the sanyo is really not an ideal choice... I don't know enough about Catalyst, whether you have any adjustment available on the individual outputs that might help...

 

I'm sorry I cant offer much encouragement, but you are very limited by the equipment you have.

 

HTH

 

Charlie

[toast]

I thought that might be what you all said. Thanks for your input - it makes me a feel a bit more confident to go back to the suppliers of the kit and grumble!

 

I had suspected that the Sanyo kit wouldn't be the greatest for this application, but it was the suppliers who spec'd it for the job - I thought I'd give it a go.

 

They probably can't afford the Barco option :)

 

Oddly enough they've chosen quote a decent screen material - I think it probably is Opera Blue, though I haven't checked.

 

The Catalyst is certainly capable of colour balancing on the outputs, it'll make the (so far very simple) progamming slightly more complex, but I think I might have to resort to it.

 

 

 

Thanks again for your comments. Any other thoughts from anyone else will be welcome too!

[Johnparrack]

First and most importantly.....u get what u pay for...if u use standard rear projection material u will get hotspots. You will also get hue/colour shifts...for example the balance will look great in the centre of the screen from the middle of the room, but will change as the viewing angle does.

Quite rightly as mentioned, go for Opera Blue...its expensive but I would think that most UK Set companies now have a piece in a fairly large size (I've done 20+++++ shows with it)..if u cant stretch to Opera Blue, then increase your soft edges...eg 100 pixels to 200 if you can re programme the material to fit...your hot spots will then be closer together, almost blending into 1...an old trick from many a moon ago!

 

Also quite rightly mentioned you are P'ing in the wind trying to use lcds to do it.but in saying that if you use the sanyo tools via ethernet u can balance the buggers...but they are still not great for softies.

 

As for R12's....myself, and 3 other projectionists balanced 16 projectors perfectly and doubled on 2 x 3 proj wide doubles (6xR12) and 2 imags(4XR12) doubled, with projectors from 2 different companies with varying lamp use/strikes....and in 20/30 minutes...no b/s here....2 peeps pushing buttons and 2 peeps radio'ing their observations. Check my website pics for examples of it..

 

hope this adds a little to the good advice already given by others.