[tom]

The speculations about color spaces in general makes sense but, I can say it's specifically not valid for any of the above examples. I don't see a saturation difference other than emitter falloff -which is already different- and the yellow barrel has no pair to compare to. It's also fairly possible to debunk such a difference using simball or cornell in seconds.

[Half Life]

True -- it's also complicated by the fact that there are alot of moving parts involved, meaning dealing with input/output colorspaces, web browsers, photo editing tools(levels, curves, etc), color management policies, and Maxwell itself. Nailing down the exact origin of the issue when it comes to color can be tricky and complex even on seemingly simple things.

I am still wrestling with the spectral colorspace (XYZ) that Maxwell uses internally because it is so foreign to anything I've worked with before... multiply that by the conversion to RGB that takes place both in the materials as well as in the render output and it can easily be complex to work out exactly what is happening where.

One thing I've always wondered -- Photo's have a very low Dynamic range and color gamut compared to "spectral" data and this is the reason why HDR's were invented in the first place... why put preference on output from Maxwell that is not HDR? (I'm talking about the default output settings).

I mean if you process a HDR/EXR in post it will be very difficult to have blown out areas or details lost in shadow unless you want/make them that way. It seems like HDR/EXR would be the output format of choice for Maxwell... file size notwithstanding.

I've not had a chance to play with the Photoshop Plugin but that seems to be ideal in the same way.

Boy, I do ramble on sometimes

Best,
Jason.

[tom]

You can pick a wide color space such as ProPhoto and save as EXR or TIFF32

[MetinSeven_com]

I have a Dell monitor, and the monitor color profile driver had some issues in the past. On top of that the color calibration driver of CS5 turned out not to be installed, so I'm using this freeware tool to calibrate my monitor colors. Works fine, I can recommend it.

[Lars Magnusson]

Hey Lars, are you having greyscale issues on opening the file or saving?

I'll post this for CS4 color management:
http://www.adobepress.com/articles/arti ... ?p=1315593

Best,
Jason.

Thanks for the link!

Hrm..this is embarrasing, I just discovered/remembered the cause and reason for my problem.
(when opening a 16bit tif displacement map it always open it in AdobeCameraRaw and forces me to apply some adobegamma2.2 profile or similar...which bothered me since I don't know if that affects the displacement.)

Reason for that was another thread here when I tested if you could take a 16bit tif from maxwell and do whitebalancing with adobecameraraw....and it was the settings I altered then (making cameraraw prefered viewer for tif ) that caused this little confusion....and it was easy to fix so now I can open the tif without forced profile

[MetinSeven_com]

Hi again guys,

I've tried the Adobe 98 color profile, burn value decrease and TIFF32 tips, and I've got renders to my satisfaction now, but I've still got the problem of the 3ds Max Fire ActiveShade preview rendering much less saturated.

In short: the Fire preview behaves perfectly as Maxwell used to render in terms of saturation, burn, etc., with the default values ( burn 0.8 ), and the final Maxwell render is much more saturated and I need to turn down the burn value to 0.2 to get a realistic saturation, and use the Adobe 98 color profile, while I've never had to do that in any Maxwell version before the latest one. On top of that, the Maxwell Fire preview renders much too desaturated and flat with these setting I have to use to get a nice final render.

I suspect the problems might have something to do with a recent change of monitor. I'm using a Dell UltraSharp U2711 27-inch monitor. But still I don't understand where the difference between the Fire render in 3ds Max and the final Maxwell render comes from.

[Half Life]

I seem to remember something about not having gamma correction set in the activeshade settings of Max -- which if it was enabled would cause the renders not to match up.

A burn of .2 is very low -- too low really... not seeing the maxwell scene file or the material settings I can only guess at what could be the culprit but something would need to be wrong in your lighting/camera exposure and /or materials to require such a drastic drop in burn value.

Best,
Jason.

[Bogdan Coroi]

@MetinSeven_com: See 5th post and Mihnea's answer on this: http://www.maxwellrender.com/forum/view ... 97&t=35707
Maybe this is your case.

[MetinSeven_com]

@MetinSeven_com: See 5th post and Mihnea's answer on this: http://www.maxwellrender.com/forum/view ... 97&t=35707
Maybe this is your case.

Thanks for the pointer, but this is not my case. I have no gamma activated in the 3ds Max options, and besides, the ActiveShade (Fire) render gives a correct result, the final render in the external Maxwell renderer is not correct (oversaturated and overexposed with the default 0.8 burn value). For the final render to approach correctness I have to set the burn value to 0.2.

As for the settings: I use the same settings I've always used for Maxwell scenes. Normal camera settings, no oversaturated materials, the works.

Somehow there's a very noticeable difference between the preview render and the final render, and a noticeable difference between former final renders and current final renders. I suspect it might have something to do with the color profile matter in conjunction with the driver of my new monitor or something like that. Maybe there's some hidden system gamma setting that is applied to the Maxwell renderer, so the gamma is accidentally doubled?

Right now I'm working around the problem by rendering to 32-bit TIFF with a burn value of 0.2 and adjusting a lot in Photoshop afterwards. That shouldn't be the right way to go of course. Any further suggestions will be greatly appreciated, thanks in advance.

[tom]

Any further suggestions will be greatly appreciated, thanks in advance.

Metin, could share an example scene?

[MetinSeven_com]

Hi Tom,

It happens with every scene, even a simple teapot test scene. I use all the standard settings in Maxwell materials, light strengths, camera settings, etcetera. I've got no gamma turned on in the 3ds Max preferences, nothing special. The same workflow has always worked fine till recently.

If no-one else is experiencing differences between the Fire ActiveShade preview and the final render, then I suspect it's due to my recent monitor change, which happened around the same time the new Maxwell version was released. But the strange thing is that in Photoshop everything looks fine, in 3ds Max (Fire preview and other renderers) everything looks fine, in XnView everything looks fine, etcetera. Only the Maxwell renderer's output gives me trouble with oversaturation and overexposure, resulting in the need for a very low burn value and Photoshop post-processing.

It's as if the Maxwell renderer uses its own color profile / gamma / whatever, as opposed to the standard system color settings every other piece of software uses.

[MetinSeven_com]

Here's a simple example of the color issue:



- Maxwell material applied to the teapot ( plastic preset, shininess 45, roughness 15, yellow color HSV: H=40, Saturation=224, Value=224 )
- Lighting performed using a HDRI environment lighting texture with normalized exposure ( been using it for years ).
- All color profile settings default ( sRGB, gamma 2.2, burn 0.8 ).
- Camera settings: fStop: 5.6, shutterspeed: 30

As you can see, the Fire preview in 3ds Max ( set to high quality ) looks nice, no oversaturation or overexposure. The Maxwell render shows a noticeable difference.

Tom, I can send you the HDR environment map if you want, so you can easily recreate this scene (I didn't save it). But the same problem occurs in any scene, including scenes that are lit with only Maxwell lights, no environment lighting.

[tom]

If you export the scene as MXS and open in Maxwell Studio, does it still happen?

[MetinSeven_com]

Yep. I exported it as an MXS, opened that in Maxwell Studio and rendered the scene in the Maxwell Studio viewport. Exactly the same oversaturated and overexposed result as in the Maxwell Render window.

Do you have any clue what could be the cause of this? Maybe something goes wrong during the translation of my Max scene to an MXS file, such as an accidentally wrong gamma, worng burn value, wrong color profile or something like that? But in that case, more Maxwell users would have this issue. So that makes me think it's got something to do with the driver of my new Dell UltraSharp U2711 monitor or my system color profile settings. But what makes this so odd is that all of my images look fine in 3ds Max (Fire preview), Photoshop, XnView, etcetera. It's only when rendering with the Maxwell renderer that the result gets too saturated and exposed.

Just let me know if I should test some other things, or if you want me to send you the MXS file and the environment lighting texture.

[tom]

What happens if you don't use IBL? Does it also happen with emitter-only illumination?