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Having big problems lighting this scene

Posted: Wed Dec 21, 2011 4:42 am
by Puck
Hi Guys,

I really hope someone can help me. I've tried several times to make a studio setting light up some of our frames correctly. The end result I want is the example file. Nice and clean white which I just can't seem to reproduce despite having the walls and lighting set to white. I'm quite inexperienced with Indigo so I'm hoping someone will have an easy solution.

The file is a Sketchup 8 document which shows what I'm rendering at the moment.

We're trying to set up a studio to do several of these but I've hit a wall with it now and I'm not sure where to turn to.

Any help or tips would be really appreciated.

Best

Puck

Re: Having big problems lighting this scene

Posted: Wed Dec 21, 2011 5:36 am
by CTZn
This relates with the camera white point; in Indigo, into the Imaging pane, expand White Point and put x=0.33 and y=0.34. These values were choosen arbitrarily to adapt to your scene.

Then exposure should bring you to the brightness you want. Eventually, lower the images B parameter to avoid burning them.

You should consider a 85% white as the maximum value for an albedo as no mate material reflects any more light in real life.

To avoid the initial biased white, make sure that emitters are at the same temperature than the camera white point. The colour should result neutral when they match.

Re: Having big problems lighting this scene

Posted: Wed Dec 21, 2011 5:45 am
by CTZn
Obviously you can pick the white point from the very rendering image, I never had to use it :)

After the quick tweak:

Having big problems lighting this scene

Posted: Wed Dec 21, 2011 6:07 am
by Headroom
Also a nice side effect of the less than 86% albedo ( as compared to 100%) is that it renders faster.
It's not easy to find information About real world measured reflectance but even the 85% are somewhat high.

Re: Having big problems lighting this scene

Posted: Wed Dec 21, 2011 7:40 am
by Voytech
Here's my take on it. Needs more tweaking.

Here's what I did.

Separated the object from the background.
Changed all lights to blackbody 6500.
Moved/added lights/changed lumen value to get twice more light in the background than on the object.

These are all photography basics. Indigo, to me, is a "artificial" camera :) Since the light physics are quite realistic in indigo, your should approach the subject as in real life. Hence, work with light rather than try to cheat by making materials too bright.

Re: Having big problems lighting this scene

Posted: Wed Dec 21, 2011 9:48 pm
by Puck
Guys, I'm blown away! Quick responses that have been incredibly helpful. Thank you Voytech for uploading a new sketchup file for me to work with. The scene lights up so much better than I was expecting. I've learnt a lot from your setup.

I don't have a good photography background so perhaps reading up on photography lighting would help me understand more? Could you tell me what blackbody 6500 is and what it means to indigo?

Thanks again guys,

Puck

Re: Having big problems lighting this scene

Posted: Wed Dec 21, 2011 10:08 pm
by dag
6500k is still magenta if you don`t use a custom wb (bug), so use white rgb lights with E white balance.

Re: Having big problems lighting this scene

Posted: Thu Dec 22, 2011 1:08 am
by Zom-B
dag wrote:6500k is still magenta if you don`t use a custom wb (bug), so use white rgb lights with E white balance.
or better a uniform light, that is white too and also 0.5 to 1% faster to render ;)