Do we really need to use Utility-sRGB-Texture for Textures instead of Utility-Linear-sRGB ? ( Too Dark Issue )

Hello, here’s an example of what doesn’t really make sense to me:


( Artwork by Alexandra Hodgson )

Left = Original image set to Out-sRGB to match the Web colors.
Middle = Utility-Lin-sRGB viewing in ACEScg ( Looks about the same just slightly less saturated which is fine i guess ).
Right = Utility-sRGB-Tex viewing in ACEScg ( That’s how 3D Software will see the textures which imo is too dark ).

Here’s another example using Utility-sRGB-Tex:

So let’s say i wanna render a poster/wallpaper of this Joker image from this website.

Here’s how it looks with Utility-sRGB-Tex:

And this is with Utility-Lin-sRGB:

This scene is lit by .HDR Env image which i’ve converted using Utility-Lin-sRGB as recommended for HDRI’s by many artists.

I’ve also tried to convert HDRI and the Web image using Utility-sRGB-Tex, but to make it bright enough i also had to enable sRGB on top of ACEScg which as a result makes it problematic or near impossible to match the images in other softwares.

And this is both Linear-sRGB ( which looks perfect to me ):

Any suggestions?

Hello there,

It seems to me when I read your question that you haven’t quite grasped the difference between Utility-sRGB-texture and Utility-Linear-sRGB ?

You basically need to use :

  • Utility - sRGB - Texture : files with a sRGB transfer function within the sRGB gamut (basically images that you may watch with the Windows viewer, most likely jpgs from Google or Photoshop).
  • Utility - Linear - sRGB : files with a linear transfer function within the sRGB gamut.

There is not one better than the other, they just have different purpose.
You could also use your ODT as an IDT to preserve the look but this is not recommended for textures for many reasons.

Did you have a look at these threads ?

Also if I may, “viewing in ACEScg” is a bit confusing. “That’s how 3D Software will see the textures” is not very accurate neither. A 3d software needs linear textures to compute proper calculation and while they may appear too dark to you, they are probably fine for the render engine.

Happy to help more if you provide more details,

Chris

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Can you specify the ODT of third image?
If its rendered in aces cg or in a linear color space
If you wanna look that image same, mention the same colour space above .

If you wanna look that image in your divices , you covert that image into jpg or png which are sRGB images, supported by sRGB display. When you render the linear color space image into sRGB like png or jpg , to view that converted images in nuke you have to use “utility sRGB textures” because it’s an sRGB image now Because you rendered in png or jpg.

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No need to convert HDR images into srgb it loses its dynamic range .
HDR images are 32 bit and sRGB images are 8-16 bit which are jpg ,png etc.

When you are using 32 bit images which are called Linear images put “utility linear sRGB”

When you are using 8 bit or 16 bit images downloaded from internet whatever ,blindly use “utility sRGB textures”

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Hi @D_Bharath,

This statement is actually quite misleading, converting an HDRI from any colourspace to sRGB will not make it loose dynamic range. This is really terminology related but sRGB is a RGB colourspace like any other and nothing says it is bounded. However, it is correct that performing a conversion with the ACES config from any OCIO Colorspace to Utility - sRGB - Texture will clamp the data.

Likewise, here, when talking about bit depth, you need to be explicit, HDR images can be 32-bit Float AND 16-bit Half, LDR/SDR imagery is indeed commonly 8-bit Int or 16-bit Int.

It might sound pedantic, but it is actually critical to use the appropriate terminology.

Why should it be particularly difficult to agree upon consistent terminology in the field of color appearance? Perhaps the answer lies in the very nature of the subject. Almost everyone knows what color is. After all, they have had firsthand experience of it since shortly after birth. However, very few can precisely describe their color experiences or even precisely define color.

Mark D. Fairchild

Cheers,

Thomas

It’s Utility-sRGB-Texture ( both HDRI and Joker pic ).

All these images are in ACEScg OCIO ( sRGB ) display it’s a screenshots of V-Ray.

As you can see in the first room image it looks terribly wrong ( the HDRI/Room is good reference for the colors captured by a camera ). I use Utility-Linear-sRGB for every texture no matter what kind of.

Maybe it’s just a thing in V-Ray or when using OCIO.

You can see this guy gets totally different result when using sRGB-Tex:


If i had his scene and did the same in V-Ray, the Captain Marvel poster for example would just look almost black.

Hi @exacomedia,

You should not do that and instead, cherry-pick the appropriate transform to get your textures into a linear RGB colourspace as mentioned by @ChrisBrejon and @D_Bharath.

  • An HDRI coming from an online vendor will likely need to be converted to the ACES working space, i.e. ACEScg with the Utility - Linear - sRGB OCIO Colorspace.
  • A SDR/LDR image from an online vendor, e.g. jpeg, png will likely need to be decoded/and converted to the ACES working space with the Utility - sRGB - Texture OCIO Colorspace.

If you don’t do that, you will not be able to render properly. I will take a look at the video.

Cheers,

Thomas

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Hi,

The video is good overall minus a few errors that I commented on: https://www.youtube.com/watch?v=RKW9Y1hMx1o&lc=UgxFjJ52bTFncmDUvex4AaABAg

Cheers,

Thomas

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