RED Alert White Balance off on build 20 footage

[Andrae Palmer]

Still frames from footage recorded with Build 20. Made sure RSX file was deleted when switching in between RED Alert and REDCine. Kelvin was set at 5600, REDspace for both. I also tested on many other clips that were shot with Build 20 under 5600 outside in sunlight.... still the same issue. The interior was lit with sunlight for this still frame.

REDCine v3.18:


RED Alert v20.1.6:


I thought the white balance issue should be the other way around. How comes RED Alert is so way off?

[Graeme Nattress]

Can you tell me what the actual color temperature of the light that was illuminating your subject was?

Graeme

[Nick Shaw]

That's exactly what I would expect to see, given that Red Alert is using the new colour science, and RedCine is not. You should NOT expect them to give the same result for the same parameters.

[Graeme Nattress]

Daylight here is usually measured around 4800k. I did a measure down at the RED offices in Lake Forest last week and it was 4900k. If you're setting the wb to 5600k when the light is not 5600k, then the warm appearance is totally correct and as expected. That is why I need to know what the measured color temperature of the light was.

Graeme

[Andrae Palmer]

Daylight here is usually measured around 4800k. I did a measure down at the RED offices in Lake Forest last week and it was 4900k. If you're setting the wb to 5600k when the light is not 5600k, then the warm appearance is totally correct and as expected. That is why I need to know what the measured color temperature of the light was.

Graeme

Great point Nattress... perhaps sunlight in Florida is more towards 4800k. I didn't have a Color Meter with me and didn't use the auto setting on camera. I always used the daylight setting before without any issues. Still it seems strange to me that REDCine got it so right and RED Alert is way off. I now have to White Balance Build 20 footage in RED Alert to get all the clips correct. I have many more clips that were shot under very bright Florida sunlight and it's still the same issue.

That's exactly what I would expect to see, given that Red Alert is using the new colour science, and RedCine is not. You should NOT expect them to give the same result for the same parameters.

From reading the Build 20 notes you would be lead to believe that REDcine would be the one with the incorrect white balance. It states that you will have to white balance Build 20 footage in REDCine. Currently I have to white balance clips in RED Alert... the other way around of what I would have expected.

[Graeme Nattress]

The original kelvin calibration before build 20 was a bit rough. It was consistent, but rough. Now it's consistent, but accurate (usually within a 100k or so of the measured value, which is pretty darn good for a camera).

Remember, the data is raw, so it's entirely conceivable that the old calibration thought white was around 5600k, and the new around 4800k, and hence the visual difference in the apps. But what did it look like in camera where you'd set it to 5600k? Did it look warm their too?

If you can shoot a kodak grey card, and do an auto-wb off that, that'd be great. If you have a real macbeth chart (not one of the copies as their colors are way off) and can shoot that under your lighting, I can always take a quick look at the R3D here and see what is going on. If you want to do that, shoot the smallest possible R3D for me and give me a pm and I'll tell you where to send it. If you know how to set up interval record, that can shoot a 1 frame R3D that's pretty small to email.

Hope that helps,

Graeme

[Andrae Palmer]

The original kelvin calibration before build 20 was a bit rough. It was consistent, but rough. Now it's consistent, but accurate (usually within a 100k or so of the measured value, which is pretty darn good for a camera).

Remember, the data is raw, so it's entirely conceivable that the old calibration thought white was around 5600k, and the new around 4800k, and hence the visual difference in the apps. But what did it look like in camera where you'd set it to 5600k? Did it look warm their too?

If you can shoot a kodak grey card, and do an auto-wb off that, that'd be great. If you have a real macbeth chart (not one of the copies as their colors are way off) and can shoot that under your lighting, I can always take a quick look at the R3D here and see what is going on. If you want to do that, shoot the smallest possible R3D for me and give me a pm and I'll tell you where to send it. If you know how to set up interval record, that can shoot a 1 frame R3D that's pretty small to email.

Hope that helps,

Graeme

Ok I'm heading outside right now and will white balance off an 18% Gray card. I will be right back.

[Graeme Nattress]

Thanks! This kind of data is very useful for me as we go forwards!

Graeme

[christopher witzke]

I'm guessing the smog in L.A. drops the CT a few hundred compared to Canada... aye?

[Graeme Nattress]

It certainly felt a 100 degrees warmer down there.... :-)

Graeme