Vray 5 vfb LUT settings

[brunonz]

Hello everyone

I am having a lot of questions on the new vray 5 LUT settings on the VFB. The "Convert to sRGB Space first " is on by default. But the image look overexposed, altough the colors look correct when i adjust the exposure.

On the other hand, when i disable the "convert to sRGB...", the overall corrections look more subtle, but the colors look a bit off.

Can i have more info on what´s the correct aproach?

Tks!

[hermit.crab]

The Convert options are used in regards to the loaded LUT in consideration of its creation method. Since this information cannot be automatically detected, we've added the convert options for users to adapt their LUT files as needed. The correct approach would be to find the matching options for the specific LUT configuration, which depend on the LUT itself.

[francomanko]

Hi, yeah im totally confused by this, any help with the actual process would be much appreciated.

So first case,

1. I add a sRGB LUT file to the layers.
2. I need to keep the "display correction" setting to the default of sRGB.

Presumably because the base layer is already in sRGB mode, i need to untick the 'Convert to sRGB space first' option in the LUT layer?

Second case

1. I add a linear LUT file to the layers.
2. I need to set the "display correction" setting to 'none'
3. I need to have the 'Convert to sRGB space first' option turned on.

Or when using a LUT, (doing some testing with comparing to Photoshop), do i always have to have the "display correction" set to none, and the 'Convert to sRGB space first' option turned on.?

Sorry for being so thick

[vladimir.nedev]

So first case,

1. I add a sRGB LUT file to the layers.
2. I need to keep the "display correction" setting to the default of sRGB.

Presumably because the base layer is already in sRGB mode, i need to untick the 'Convert to sRGB space first' option in the LUT layer?

If you have a LUT file that expects the input image to have sRGB gamma, it usually outputs an image that has sRGB gamma as well.
These are the LUTs that come with Photoshop as well as most LUTs you will find by searching in google.

For them, you need to keep 'Convert to sRGB space first' enabled, so the VFB image will be converted to sRGB gamma before the LUT is applied to it.
You then have to set the display correction to "None". If you leave it at sRGB, you will apply the sRGB gamma twice.

Second case

1. I add a linear LUT file to the layers.
2. I need to set the "display correction" setting to 'none'
3. I need to have the 'Convert to sRGB space first' option turned on.

Or when using a LUT, (doing some testing with comparing to Photoshop), do i always have to have the "display correction" set to none, and the 'Convert to sRGB space first' option turned on.?

In this case you have to disable 'Convert to sRGB space first' and keep the "display correction" set to 'sRGB'.

I think we have some improvements to make with the default values here, as out of the box both sRGB and Linear LUTs will not work correctly.

Also, because the LUT layer keeps the image in whatever gamma it was left by the LUT file, it's impossible to use the "opacity" slider with sRGB LUTs, as you will be blending between an image with linear gamma and an image with sRGB gamma.
So we might have to rethink how the LUT layer works.

Greetings,
Vladimir Nedev

[Bigguns]

It's a mess, I can't get these Lut's to work correctly.. you guy's should copy what corona does... WAY BETTER and simpler..