Frustration with converting canvas EXRs

SnowSultan

I don't remember having this much trouble the last time I did this, so I wonder if something changed in a recent Studio?...

Anyway, does anyone know the proper workflow for converting EXRs (rendered from canvases) in Photoshop so they can be combined and reassembled properly? I've done a decent amount of research into this and can't find any agreed-upon answer, even from those using higher-end software.

 

- Some say that when converting it from 32-bit to 16-bit, you're supposed to choose Exposure and Gamma and leave it at the default settings of 0 Exposure and 1 Gamma. That makes everything completely white until you turn the Exposure down to -13. This *seems* to make sense, seeing how the default Exposure settings of Studio's Tone Mapping are also 13.

- Numerous sources say to combine the layers using the Linear Dodge (Add) blending mode. For me, this makes everything blindingly bright and is completely useless. I have better luck using Screen, but that still lightens the image more than it should in the end.

 

This Keyshot page gives information that again, *should* work, but gives very different results with the EXRs from Studio. I did the same steps that it mentions at the bottom with a four layer canvas stack in Photoshop and the final result is so bright, it hurts to look at.

https://luxion.atlassian.net/wiki/spaces/K8M/pages/315588719/

 

Do I just not know the established way to do this or is there really no established way? Thanks in advance for any help, I kinda need to figure this out soon.

deathbycanon

I lower my exposure 1st then choose exposure and gamma and leave it a the default settings. 

https://youtu.be/xEe2r5m7Fto?t=308

if I use a blending mode on a canvas I have already changed the exposure on it before I use a blending mode... 

Richard Haseltine

Is Tone Mapping off in DS?

Leonides02

SnowSultan, are you trying to layer Light Groups?

SnowSultan

Thanks deathbycanon, I will give that a try as well. I know how to adjust all of those things, paint with layer masks, etc, I'm just trying to figure out if there is a reliable procedure that should be followed to get consistent results.

Richard: No it is on, otherwise the scene would be completely white. Should it be turned off when rendering EXRs?

Leonides: Not for this example, I know those should use Lighten when combined (unless there's a better way for those as well?)

Richard Haseltine

SnowSultan said:

Thanks deathbycanon, I will give that a try as well. I know how to adjust all of those things, paint with layer masks, etc, I'm just trying to figure out if there is a reliable procedure that should be followed to get consistent results.

Richard: No it is on, otherwise the scene would be completely white. Should it be turned off when rendering EXRs?

That is certainly the advice I have been given - since you are working with a very high bit-depth it makes sense to work linearly (no corrections, other than de-gammaing the maps) and then make adjustments to the finished renders.

SnowSultan said:

Leonides: Not for this example, I know those should use Lighten when combined (unless there's a better way for those as well?)

 

SnowSultan

I tried rendering with Tone Mapping off, and it does work, but you can't see what you're getting. You can't preview it in the Viewport and the end result is good, but slightly more saturated than the Iray preview. i wish there was consistency with Iray between programs, it's insane that Iray in Substance Painter gives really different results than the exact same thing with the exact same HDRI in the exact same position in an Iray Studio render.

Also, I still don't know what the "true" conversion (if there is one) is supposed to be. If you don't use Tone Mapping, is -13 still the right Exposure? Is there even a correct target Exposure? I don't know, I'm just the kind of person that wants accuracy and consistency, and if it's always up to me to make it look "right", I'm always going to have doubts that I'm doing it right.

plasma_ring

SnowSultan said:

I tried rendering with Tone Mapping off, and it does work, but you can't see what you're getting. You can't preview it in the Viewport and the end result is good, but slightly more saturated than the Iray preview. i wish there was consistency with Iray between programs, it's insane that Iray in Substance Painter gives really different results than the exact same thing with the exact same HDRI in the exact same position in an Iray Studio render.

Also, I still don't know what the "true" conversion (if there is one) is supposed to be. If you don't use Tone Mapping, is -13 still the right Exposure? Is there even a correct target Exposure? I don't know, I'm just the kind of person that wants accuracy and consistency, and if it's always up to me to make it look "right", I'm always going to have doubts that I'm doing it right.

I always use -13 unless I get it into Photoshop and realize I could stand to start with a lighter or darker base render. But that's the most accurate, in my experience. I typically leave tone mapping alone at default settings unless I want a specific aesthetic effect. (And I just remembered: I did adjust the default gamma recently to 2.20). 

 

Theme3D

The problem is that the daz default tonemapping settings are to bright. So all the illumination in daz ends up too bright. That's why the exr HDR is looking blown out, because it is.

To get the tonemapping to match your HDR do the following:

• Film iso = 0
• Burn Highlights = 1.0
• Crush Blacks = 0
• Gamma = 2.2 (to actually preview how the lightning will be, must add gamma 2.2 in comp later)

Now all the lights in your render needs to be toned down drastically. enviroment light needs to be 0.0001 or something like this, go test!

The benefits of this is better dynamic range, and a HDR that works like other rendering software. The bad is if you get a asset, they will come with light blowing, so all intensities need to be adjusted.

Good luck.

Leonides02

Theme3D said:

The problem is that the daz default tonemapping settings are to bright. So all the illumination in daz ends up too bright. That's why the exr HDR is looking blown out, because it is.

To get the tonemapping to match your HDR do the following:

• Film iso = 0
• Burn Highlights = 1.0
• Crush Blacks = 0
• Gamma = 2.2 (to actually preview how the lightning will be, must add gamma 2.2 in comp later)

Now all the lights in your render needs to be toned down drastically. enviroment light needs to be 0.0001 or something like this, go test!

The benefits of this is better dynamic range, and a HDR that works like other rendering software. The bad is if you get a asset, they will come with light blowing, so all intensities need to be adjusted.

Good luck.

Wow -- this is good info! I'd never heard this before, but these settings absolutely make a difference. 

What do you mean by "must add gamma 2.2 in comp later" ?

Theme3D

Leonides02 said:

Theme3D said:

The problem is that the daz default tonemapping settings are to bright. So all the illumination in daz ends up too bright. That's why the exr HDR is looking blown out, because it is.

To get the tonemapping to match your HDR do the following:

• Film iso = 0
• Burn Highlights = 1.0
• Crush Blacks = 0
• Gamma = 2.2 (to actually preview how the lightning will be, must add gamma 2.2 in comp later)

Now all the lights in your render needs to be toned down drastically. enviroment light needs to be 0.0001 or something like this, go test!

The benefits of this is better dynamic range, and a HDR that works like other rendering software. The bad is if you get a asset, they will come with light blowing, so all intensities need to be adjusted.

Good luck.

Wow -- this is good info! I'd never heard this before, but these settings absolutely make a difference. 

What do you mean by "must add gamma 2.2 in comp later" ?

The exr HDR ignores the tonemapper. So we are using gamma 2.2 for visualization purposes and correcting lightning of the scene. If you try to light your scene in gamma 1.0 (linear) the lights are not behaving correctly.

Some image editing software do automatticly application of the gamma 2.2, so you can preview the HDR image correctly. Some don't. So that's what I meant.

When editing the HDR you need to apply gamma 2.2 (not baking yet, just previewing). Do your comp, adjust colors, correct the crush blacks and burn highlights to bring contrast etc. Apply gamma 2.2 (baking) to correcting exposure and save your file 8bit file.

I didn't test this workflow enough yet. But maybe it breaks the skin shaders settings(?) or other material settings due to light intensities being lower (???). But it should give more predictible results.

Sevrin

deathbycanon said:

I lower my exposure 1st then choose exposure and gamma and leave it a the default settings. 

https://youtu.be/xEe2r5m7Fto?t=308

if I use a blending mode on a canvas I have already changed the exposure on it before I use a blending mode... 

This is one of the videos that helped me get started with compositing canvases.  Sickleyield's YT channel also includes a good video on canvases that includes some additional possibilities..  Both are very helpful for introducing you to the workflow.  I use Affinity Photo for editing, but that, Ps and GIMP all do the basic stuff very similarly.  What canvases to use and how to use them varies from project to project.  That only comes with experience.

Leonides02

 

Theme3D said:

The exr HDR ignores the tonemapper. So we are using gamma 2.2 for visualization purposes and correcting lightning of the scene. If you try to light your scene in gamma 1.0 (linear) the lights are not behaving correctly.

Some image editing software do automatticly application of the gamma 2.2, so you can preview the HDR image correctly. Some don't. So that's what I meant.

When editing the HDR you need to apply gamma 2.2 (not baking yet, just previewing). Do your comp, adjust colors, correct the crush blacks and burn highlights to bring contrast etc. Apply gamma 2.2 (baking) to correcting exposure and save your file 8bit file.

I didn't test this workflow enough yet. But maybe it breaks the skin shaders settings(?) or other material settings due to light intensities being lower (???). But it should give more predictible results.

Hm. After using your settings, I've been bringing the EXR into Photoshop. I don't think a Gamma adjustment is necessary. Then, I apply the famous "filmic" look from Blender in Photoshop using the OpenColorIO plugin. This makes a world of difference when it comes to realism in renders.

I actually think the skin settings respond better with the lower light as your perscribed. 

Sevrin

Oh, and most times you won't have a need for this much granulaity, but you can do some cool stuff with the Light Path Expressions (LPE) parameters, as well.  The canvas options are Daz Studio's way of translating what we choose in canvas options, and then translating it to LPE to pass to Iray, but if you only want, for example, reflected light or only direct light, you can specify all that kind of stuff by specifying what you want using the LPE canvases and then typing your LPE in the text box provided.

https://blog.irayrender.com/post/76948894710/compositing-with-light-path-expressions

Leonides02

Theme3D said:

The problem is that the daz default tonemapping settings are to bright. So all the illumination in daz ends up too bright. That's why the exr HDR is looking blown out, because it is.

To get the tonemapping to match your HDR do the following:

• Film iso = 0
• Burn Highlights = 1.0
• Crush Blacks = 0
• Gamma = 2.2 (to actually preview how the lightning will be, must add gamma 2.2 in comp later)

Now all the lights in your render needs to be toned down drastically. enviroment light needs to be 0.0001 or something like this, go test!

The benefits of this is better dynamic range, and a HDR that works like other rendering software. The bad is if you get a asset, they will come with light blowing, so all intensities need to be adjusted.

Good luck.

What should the Exposure Value / Shutter Speed be?

Theme3D

Leonides02 said:

Theme3D said:

The problem is that the daz default tonemapping settings are to bright. So all the illumination in daz ends up too bright. That's why the exr HDR is looking blown out, because it is.

To get the tonemapping to match your HDR do the following:

• Film iso = 0
• Burn Highlights = 1.0
• Crush Blacks = 0
• Gamma = 2.2 (to actually preview how the lightning will be, must add gamma 2.2 in comp later)

Now all the lights in your render needs to be toned down drastically. enviroment light needs to be 0.0001 or something like this, go test!

The benefits of this is better dynamic range, and a HDR that works like other rendering software. The bad is if you get a asset, they will come with light blowing, so all intensities need to be adjusted.

Good luck.

What should the Exposure Value / Shutter Speed be?

Here when I set the Film Iso to 0, it automatically set -2 exposure. And the other parameters doesn't make any difference.

I have one question, I tested the filmic look of blender and it's not that good. It is a ok tonemapper, but far from great. The whole point of using these are only if you using Acescg workflow which Daz doesnt support. So why use it? I would like to see some comparision if possible.

I wanted to have the tonnemapping of daz in other software with exr, is this possible?

Thanks.

Leonides02

Theme3D said:

Leonides02 said:

Theme3D said:

The problem is that the daz default tonemapping settings are to bright. So all the illumination in daz ends up too bright. That's why the exr HDR is looking blown out, because it is.

To get the tonemapping to match your HDR do the following:

• Film iso = 0
• Burn Highlights = 1.0
• Crush Blacks = 0
• Gamma = 2.2 (to actually preview how the lightning will be, must add gamma 2.2 in comp later)

Now all the lights in your render needs to be toned down drastically. enviroment light needs to be 0.0001 or something like this, go test!

The benefits of this is better dynamic range, and a HDR that works like other rendering software. The bad is if you get a asset, they will come with light blowing, so all intensities need to be adjusted.

Good luck.

What should the Exposure Value / Shutter Speed be?

Here when I set the Film Iso to 0, it automatically set -2 exposure. And the other parameters doesn't make any difference.

I have one question, I tested the filmic look of blender and it's not that good. It is a ok tonemapper, but far from great. The whole point of using these are only if you using Acescg workflow which Daz doesnt support. So why use it? I would like to see some comparision if possible.

I wanted to have the tonnemapping of daz in other software with exr, is this possible?

Thanks.

Thanks for the reply!

Personally, I bring the EXR into Photoshop and apply the Blender filmic. I'm experimenting with also applying ACEScg in Photoshop.

I also export the EXR to Aurora HDR or Affinity, both of which handle EXR's much better than Photoshop. But it's important to download the Exr-IO plug-in (which is free), which allows you to actually save 32-bit EXR files. For some bizarre reason, Photoshop clips them.

I'll post comparisons when I get a chance!

Sevrin

For Affinity Photo, I use the macros linked in the description linked in this video by Affinity Photo's product expert at Serif.  It's a one-click solution and no plugin is required.  There are a few options ranging from low to very high contrast, and you can dial them out a bit if you find the effect too strong.

SnowSultan

Sorry for the delay, I've been fighting with all sorts of other Studio issues the last two days.

Thank you for that tip Theme, it really works and the EXR doesn't need any adjustments in Photoshop. I will experiment with combining canvases using it, as well as the LPE settings that Sevrin linked to (finally, instructions for them that aren't incomprehensible).

Also, I wonder if the crazy exposure in Studio might explain why we have to crank lights up to 50,000 lumen to get any noticable amount of light out of them.