32 or 24 bits HDR?

[kostenurka]

Hello,

I would like to know if 32 or 24 bit HDR should be used by vray for better performance?
thanks

[Svetlozar Draganov]

Helle kostenurka,

Are you talking about 32bit HDR ( 32+32+32 = 96 bit per pixel) and 8bit HDR ( 8+8+8 = 24bit per pixel) ?
Vray will handle both formats the same way , but 8bit HDR will be faster because it contains much less information that 32Bit exr , and the file size is much smaller than 32bit HDR.
You have to know that 8bit HDR are considered as a Low Dynamic Rage image - they are very far from the range that 32bit HDR can provide.
As a conclusion > if you need quality you have to pick 32bit HDR , if you need speed use 8bit HDR.

[kostenurka]

Hi Svetlozar,

thanks for replying. I have clear idea of difference between 32bit and 24bit hdr as I do hdri on my own.. and yep, 8bit HDR (true) is not existing Just wanted to know if the difference 24/32 would make sense in obtaining maximum reality within vray.

thanks again!
cheers!

Helle kostenurka,

Are you talking about 32bit HDR ( 32+32+32 = 96 bit per pixel) and 8bit HDR ( 8+8+8 = 24bit per pixel) ?
Vray will handle both formats the same way , but 8bit HDR will be faster because it contains much less information that 32Bit exr , and the file size is much smaller than 32bit HDR.
You have to know that 8bit HDR are considered as a Low Dynamic Rage image - they are very far from the range that 32bit HDR can provide.
As a conclusion > if you need quality you have to pick 32bit HDR , if you need speed use 8bit HDR.

[Micha_cg]

I thought HDRI are available as 32bit and 16bit (also see Photoshop image mode adjustment 8-16-32). But I'm not sure 16bit was working well. If I understand right 24bit means RGB 8bit plus alpha.

[Svetlozar Draganov]

For the maximum reality you should you 32bit floating point HDRs