After apply LUT problem

[jackieteh]

Hi, sorry it’s a question about LUT again, the 1st image is after apply LUT and the 2nd image is before apply LUT, image after apply LUT look too dark or too ontrast?
client complain cannot see detail in the dark shadow, how can i improve this?

LUT use:Kim Amland - Photographic 01.cube

[leehumphries]

Something i spent ages trying to work out what was going on. I even emailed the person who made the LUT’s to ask. He was mainly Corona. I finally worked out that you need Amland photographic Linear LUT. They were posted on the Corona forum. While attempting to work out like yourself why everything went so dark, i tried using the in bult ones in Corona and using the 01 and 01 Linear version in Vray. Then realised the Linear was the correct one.

If im wrong i would love to know whats going on with them.

[tue_nguyen]

@jackieteh

Hi, sorry it’s a question about LUT again, the 1st image is after apply LUT and the 2nd image is before apply LUT, image after apply LUT look too dark or too ontrast?
client complain cannot see detail in the dark shadow, how can i improve this?

LUT use:Kim Amland - Photographic 01.cube

I used LUT from corona like you and my suggest is: lower contrast and adjustment level if you need.

[jackieteh]

@tue_nguyen

I used LUT from corona like you and my suggest is: lower contrast and adjustment level if you need.

I am not sure, yesterday i found some info from the net saying that we have to turn off sRGB to get the correct result, which one is the correct one?
anyway i will go and download the Amland photographic Linear LUT to give it a try, will post the result later.

[kosso_olli]

The way I do it is by ticking the “Convert to log space” and then disabling sRGB. The result should be like the linear ones.
I use the LUTs that come standard with Corona.

[jackieteh]

@kosso_olli

The way I do it is by ticking the “Convert to log space” and then disabling sRGB. The result should be like the linear ones.
I use the LUTs that come standard with Corona.

as you can see in 3rd image, i un tick the “Convert to log space” but enable sRGB, it seem like can get the same result as the linear one, my question is which one is correct method?
this LUT issue has become like the linear work flow issue in the previous, everyone looking for the correct method but hard to find one, hoping chaosgroup guy can give me some guideline, thank you.

[jackieteh]

@kosso_olli

The way I do it is by ticking the “Convert to log space” and then disabling sRGB. The result should be like the linear ones.
I use the LUTs that come standard with Corona.

just try your method in others project, by ticking the “Convert to log space” and disabling sRGB, my image looking wash out, just like it has double gamma

[tue_nguyen]

@jackieteh

image 1: LUT used: Kim Amland - Photographic 01
image 2: no LUT
image 3: LUT used: Kim Amland - Photographic 01 Linear
( All 3 images also have sRGB enable in VFB, because i have read some article mention to disable the sRGB if we want to use LUT in vray VFB.)

The LUT Kim Amland - Photographic LUTs Normalized is abit darker than Kim Amland - Photographic 01, so i didn’t made a copy to post, it look like the Kim Amland - Photographic 01 Linear is the correct one.
But i am wonder how could we find out which LUT is linear one if we use difference LUT file i the future?

It’s not about sRGB. With me sRGB just for gamma setting (in color mapping) and i never change it again.
About LUT just adjustment contrast and you will have correct result.

[jackieteh]

@tue_nguyen

It’s not about sRGB. With me sRGB just for gamma setting (in color mapping) and i never change it again.
About LUT just adjustment contrast and you will have correct result.

Do you mean it is no need to turn off sRGB to apply LUT?

[tue_nguyen]

@jackieteh

Do you mean it is no need to turn off sRGB to apply LUT?

No it’s not your problem. Why you don’t try play with exposure setting? Just keep your lut and try change contrast, highlight, …

[tue_nguyen]

Update: I upgrade to Vraynext. It’s really faster IPR ( BF+LC calculate) but still slow when load geometry. How to improve it? SSD is solution?

[vlado]

@tue_nguyen

Update: I upgrade to Vraynext. It’s really faster IPR ( BF+LC calculate) but still slow when load geometry. How to improve it? SSD is solution?

It’s always super helpful if you can get us a scene that we can profile here and optimize the slow part, if possible. You can send an example scene to support@chaosgroup.com

Best regards,
Vlado

[tue_nguyen]

@vlado

It’s always super helpful if you can get us a scene that we can profile here and optimize the slow part, if possible. You can send an example scene to support@chaosgroup.com

Best regards,
Vlado

Thank you so much!