Color Transform non sRGB color rendering options in Daz Studio

Comments

• Wanderer Posts: 957

  February 2018

  Okay, I just stumbled across the video myself, and doing a Google search found this thread, which absolutely nobody has touched in almost a year. So, I have to ask, could somebody with a deep understanding of Iray and Daz Studio attempt to talk about what, if anything, this says about photorealism in our Daz/Iray renders? Is there anything from this video that could be useful to us as Daz/Iray users?
• agent unawares Posts: 3,513

  February 2018 edited February 2018

  If you want to play with high dynamic range, you're going to want to start rendering Beauty canvases in Iray instead of normal images. This will give you an image that has a huge amount of dynamic range, more than you will ever actually want to use. Then, tonemap in Photoshop or Nuke or Natron or what have you, so you can get a result that flattens a lot of the dynamic range down into the final image. This can give you a result that lights a scene more closely to how your eye would "see" it versus how a camera would record it or how it renders by default.

  Post edited by agent unawares on February 2018
• Padone Posts: 4,019

  February 2018 edited February 2018

  I do not consider myself an expert in this field but I feel I can bring some light on the subject. Also, the video from Blender Guru is quite a mess. It does some major confusion between sRGB and sRGB EOTF. The same as it does some confusion between the CMS and the filmic view transform .. 

  1) sRGB is the color space of the monitor. That is, it's the "color palette" the monitor is able to use to show you any picture. It's not "bad" or "obsolete" at all.

  2) sRGB EOTF is a transfer function from linear space to sRGB space. That is, it is a translation from "real colors" to the sRGB color palette of the monitor.

  3) The filmic view trasform, that's the filmic option in Blender 2.79, is just another transfer function from linear to sRGB, the same as sRGB EOTF. The difference is that it's a better function. That is, it gives a better perception in the sRGB space of what the human eyes would see in the real world with real colors. In short. The filmic view trasform is better than sRGB EOTF because it translates better the human eyes perception from linear to sRGB.

  In Iray there is an equivalent feature in the tone mapping panel. There you can set burn highlights and crush blacks to zero to achieve an effect similar to the Blender filmic view transform. Then you may want to adjust the contrast to "balance" the image back, the same as you do in Blender.

  A very important point to consider though, is that there's not really a "better" or "worse" case. It all depends on what you want to "simulate" in your render. The standard parameters simulate better a real camera behaviour, where over-exposure may happen depending on the camera settings and lighting conditions. While the filmic view simulates better the human eye, that always adapt to the lighting conditions by adjusting the iris aperture, so it "never" gets over-exposed. So the human "mental" perception is some sort of normalized hdri. That's what the filmic view in Blender and burn highlights in DAZ Studio do.

   

  EDIT. What suggested by @agent unawares is similar. You just do it in post instead of directly in the rendering. In my opinion working in post is better anyway because you can always "undo" if you change your mind.

  

  

  tone-mapping.jpg

  486 x 356 - 60K

  Post edited by Padone on February 2018
• zaid_pixelpro32_10c9fe201f Posts: 49

  July 2018

  Wanderer said:

  Okay, I just stumbled across the video myself, and doing a Google search found this thread, which absolutely nobody has touched in almost a year. So, I have to ask, could somebody with a deep understanding of Iray and Daz Studio attempt to talk about what, if anything, this says about photorealism in our Daz/Iray renders? Is there anything from this video that could be useful to us as Daz/Iray users?

  Same same... I just asked the same question! Daz3D has a simple yet very powerful workflow, concept and rendering engine... If this only gets corrected.
• Takeo.Kensei Posts: 1,303

  July 2018 edited July 2018

  agent unawares said:

  If you want to play with high dynamic range, you're going to want to start rendering Beauty canvases in Iray instead of normal images. This will give you an image that has a huge amount of dynamic range, more than you will ever actually want to use. Then, tonemap in Photoshop or Nuke or Natron or what have you, so you can get a result that flattens a lot of the dynamic range down into the final image. This can give you a result that lights a scene more closely to how your eye would "see" it versus how a camera would record it or how it renders by default.

   

  Padone said:

  I do not consider myself an expert in this field but I feel I can bring some light on the subject. Also, the video from Blender Guru is quite a mess. It does some major confusion between sRGB and sRGB EOTF. The same as it does some confusion between the CMS and the filmic view transform .. 

  1) sRGB is the color space of the monitor. That is, it's the "color palette" the monitor is able to use to show you any picture. It's not "bad" or "obsolete" at all.

  2) sRGB EOTF is a transfer function from linear space to sRGB space. That is, it is a translation from "real colors" to the sRGB color palette of the monitor.

  3) The filmic view trasform, that's the filmic option in Blender 2.79, is just another transfer function from linear to sRGB, the same as sRGB EOTF. The difference is that it's a better function. That is, it gives a better perception in the sRGB space of what the human eyes would see in the real world with real colors. In short. The filmic view trasform is better than sRGB EOTF because it translates better the human eyes perception from linear to sRGB.

  In Iray there is an equivalent feature in the tone mapping panel. There you can set burn highlights and crush blacks to zero to achieve an effect similar to the Blender filmic view transform. Then you may want to adjust the contrast to "balance" the image back, the same as you do in Blender.

  A very important point to consider though, is that there's not really a "better" or "worse" case. It all depends on what you want to "simulate" in your render. The standard parameters simulate better a real camera behaviour, where over-exposure may happen depending on the camera settings and lighting conditions. While the filmic view simulates better the human eye, that always adapt to the lighting conditions by adjusting the iris aperture, so it "never" gets over-exposed. So the human "mental" perception is some sort of normalized hdri. That's what the filmic view in Blender and burn highlights in DAZ Studio do.

   

  EDIT. What suggested by @agent unawares is similar. You just do it in post instead of directly in the rendering. In my opinion working in post is better anyway because you can always "undo" if you change your mind.

  You're in the few persons I've seen making correct answers about the video and the topic. The video is indeed a mess of many concept

  I'll just add that I don't think photoshop is a good idea and I don't think Gimp is the best answer either

  Best way would be to stick to a compositing software like nuke, natron, blackmagic fusion. However that would be offline tonemapping

  The goal of filmic blender is to get a direct feedback before final render, so that you can adjust lightning and shading before running the full render

  So really, if you want to stick to the spirit of fimic blender, you should use the integrated tonemapper

  Mec4d once posted some settings for the Iray tonemapper. But I never checked if these were correct/useable.

  What has to be found is blender's filmic color transform equivalent settings for the Iray tonemapper

  Post edited by Takeo.Kensei on July 2018