nightly build white balance look difference

[cmjohncheng]

testing nightly build, white balance look difference.

first one is physical camera set white balance to 6500 and render,

second one physical camera white balance set Neutral use frame buffer color correction set white balance to 6500.

[vlado]

Do you have anything in the scene (f.e. a VRayLightMtl material) with "compensate camera exposure" enabled?

Best regards,
Vlado

[cmjohncheng]

no, test with box scene, vraysky + sun only, result is same
attachment include box scene file.

[svetlozar.draganov]

Could you please specify which Vray versions you've used for this test ?
For the Nightly Build we will need to know either its release date or its revision number.

Thank you very much in advance.

[cmjohncheng]

vray_adv_30505_max2015_x64_24320

[svetlozar.draganov]

And the other one is 3.00.03 ?

[cmjohncheng]

no, both are same, vray_adv_30505_max2015_x64_24320

[svetlozar.draganov]

Ooh sorry, I thought you used different Vray builds.
I got the same result here - will forward the case to our developers and let you know when we have some news about it.

[svetlozar.draganov]

The difference actually comes from Color Mapping Type.
In the first case where you render with White Balance from Physical camera the effect is applied exponentially since you are using Reinhard Color Mapping with Burn Value 0.2
When you apply White Balance from VFB it is applied Linearly - that's why the result is different.

If you switch Color Mapping Type to be Linear or change Burn Value of Reinhard to 1.0 Vray will apply white-balance from the PhysicalCam linearly and it would be the same as the one applied from VFB.

[Dariusz Makowski (Dadal)]

The difference actually comes from Color Mapping Type.
In the first case where you render with White Balance from Physical camera the effect is applied exponentially since you are using Reinhard Color Mapping with Burn Value 0.2
When you apply White Balance from VFB it is applied Linearly - that's why the result is different.

If you switch Color Mapping Type to be Linear or change Burn Value of Reinhard to 1.0 Vray will apply white-balance from the PhysicalCam linearly and it would be the same as the one applied from VFB.

Should he not change the burn value to 0 to match linear?

[svetlozar.draganov]

Nope , Burn Value = 1 means Linear , Burn Value = 0 means Exponential

[Dariusz Makowski (Dadal)]

Nope , Burn Value = 1 means Linear , Burn Value = 0 means Exponential

Ohh how strange. I could swear that if I use Reinhard and I wanted to match it to Linear I had to set the burn value to 0, o.o. O well I'm getting old, its official.