Some RWF tryings

[instinct]

that wouldnt solve a thing. as LDR textures would still be sRGB and converted on the fly...wich might look ueberstupid on some :////

Regards,
Thorsten

[jujubee]

huh? With LWF setup as it stands, textures (let's not confuse people Instinct with LDR or HDR terminology here) should be set to 2.2 input in Max preferences.

I don't understand how that could 'screw' things up any more than Max does by default. I think you have your information wrong - or perhaps I'm just misunderstanding you.

[BELCORP_SAC]

Im trying to use LWF for a while, i can clearly see that i can get a better distribution of light, plus better color bleeding( as well as i get quicker render times), I see that mi interior renderings have improved but in my exterior I have a lot of truebles with material color an map colors control.I tried leles .255 workflow but in some times I get good colors and sometimes not, Idont know what I am doing wrong. Im using vray 1.5 with vray sun and sky with pys cam.

If anybody can clear the subject about how to use correctly material colors and maps for color concordancy?

Thanks a lot

Onz

[jujubee]

I hate to hijack this guy's thread, but I'll try to answer your questions.

If in Max preferences, you have it set to 2.2 input, then you don't need to colorcorrect bitmaps.

As for diffuse/plain color swatches:
1) Get specific RGB color value (such as a wall paint from the manufacturer.)
2) Put a Vraycolor map in the empty button next to the diffuse color.
3) Put the RGB values in the grey swatch there.
4) Done.

As for exteriors and Vraysun/sky + camera - I haven't been able to get good results. I think it has something to do with the Vraysky not contributing enough bluish GI in the shadow areas.

[beestee]

As for exteriors and Vraysun/sky + camera - I haven't been able to get good results. I think it has something to do with the Vraysky not contributing enough bluish GI in the shadow areas.

I wonder if embedding the VRaySky in a colorcorrect map with gamma adjusted to 2.2 would fix this?

[jujubee]

Tried that long ago - nope.

[paulison]

I get consistent results without using LWF. Sure my rendering times may be slightly longer than by cranking up the gamma but i am using light sources to brighten the scene, not a blanket blast of gamma radiation to everything which IMHO makes many LWF images look flat and fake.

Works for some, doesn't work for others. I guess my main issue for wanting to use LWF at the moment is because when clients pick out colours, I always have to enter the RGB values and adjust by estimation the level of correction required to these values in order to make it render out correctly in vray (usually i have to darken the colour).

I found the thread regarding the difference between linear grey point (12 and 'exponential' grey point (186?) as being the main reason why my greys and colours arnt correct very interesting. I guess that i've been manually adjusting values by a similar amount for a long time and am used to doing it this way despite it not being very accurate - it relies on experience to know how to adjust certain colours.

So anyway, my conclusion is that if you use LWF, maybe there is less estimation required so although i prefer not to use this method it has its merits. If you arnt able to use LWF for exteriors because of issues regarding vray sun/sky not being tweaked to work correctly with it then i'll not be attemting to make the transition personally.

RWF is basically LWF but its pretty close to a compromise between the two methods similar to how some professionals have been using 1.8 gamma instead of 1.0 or 2.2 for years.

One thing that i'm wondering. Is LWF really solving the problem? does it accurately correct all colour from an 'exponential' range back to linear by only changing the gamma or is it just approximating things? BTW i'm calling it exponential colour range because this is how it was referred to in article posted by instinct a page or two back in this thread.

Its all a healthy discussion and although i'm not using LWF I want to sit on the fence and see how things pan out before making the leap. I dont think i'm missing anything at the moment but please correct me if needed!

[instinct]

Well when it comes to linear we are only discussing what it does to lights and materials. But it has a just as big impact in post (yes i am repeating myself and i wont stop till i rule the woooorld *cough*cough* did that come out loud ?). It makes things very unpredictable in many cases. Sure you can estimate and compensate with experience but when you wouldnt have to you could use that experience and estimation times for something different : making better pictures

There sure are a lot of letdowns, especially since i dont know of any app out there besides nuke and some commandline stuff that is even capable to fully work in linear. Of course as Max is non-linear by default going linear provides a whole new world of pitfalls (like gamma correcting procedurals and alike).

VRaySun and Sky beeing off wasnt an issue for us so far as we hardly ever use them due to the nature of our projects. I understand that this is a pretty big issue for many users out there tho!

Kind Regards,
Thorsten

P.S. "Professionals using 1.8" wasnt that because Macs use 1.8 instead of the windows 2.2 ? could be off track there but something is ringing in the back of my head *scratching*

[rmejia]

As for exteriors and Vraysun/sky + camera - I haven't been able to get good results. I think it has something to do with the Vraysky not contributing enough bluish GI in the shadow areas.

The white balance in the camera might be knocking out the blue from the sky. With a Neutral white balance I get a bluish tint all over the place.

[jujubee]

s LWF really solving the problem? does it accurately correct all colour from an 'exponential' range back to linear by only changing the gamma or is it just approximating things?

Yes it really is solving the problem from a mathematical standpoint by equalizing the main applications. Then it's up to the rendering engine and the materials to be properly adjusted to get them all to 'sync' properly - if there's an error there than there is an error there...

@rmejia - I've been thinking about this and you may be right, but I need to test it. I know Androkinos has been getting spectacular results on his exteriors with LWF - I'm not quite sure what he is doing to tweak his scenes. White Balance is quite funny - if you are off slightly with a specific WB color it totally changes the atmosphere of a scene. This is one major reason why I wish WB could be adjusted dynamically in the VFB.

[dlparisi]

As for exteriors and Vraysun/sky + camera - I haven't been able to get good results. I think it has something to do with the Vraysky not contributing enough bluish GI in the shadow areas.

I've gotten pretty good results using the sun/sky so I'm curious what problems you are having. My gut tells me that vraysky is already set up to work correctly in linear space rather than the other way around (meaning it doesn't need to be in a colorcorrect map to output correctly) but I could be wrong. Either way I'm happy with the results I get and rarely need to adjust the sky output (I do this mainly for sunrise and sunset images where I'm trying to get a nice warm soft glow from the sky).

Works for some, doesn't work for others. I guess my main issue for wanting to use LWF at the moment is because when clients pick out colours, I always have to enter the RGB values and adjust by estimation the level of correction required to these values in order to make it render out correctly in vray (usually i have to darken the colour).

You can easily generate the correct gamma corrected color by using the vraycolor map and setting your gamma to 2.2 and entering the rgb values in the color color selector. Works every time.

The white balance in the camera might be knocking out the blue from the sky. With a Neutral white balance I get a bluish tint all over the place.

Same here, I usually just adjust it in photoshop. This mainly shows up on interiors where there is a large skylight vs. direct light relationship.


Personally, I use LWF on every project - interior and exterior and couldn't be more pleased with the results. My intent is to get better light and color distribution in the images. I don't however go the final step and do all of my post production in linear as Thorsten does. The advantages to keeping it linear are obvious but since most of my work is stills, and photoshop really doesn't support working linearly I usually just bake the gamma into the saved FB image. Yeah, I could use a linear profile (e.g., AIM RGB) in photoshop but I then have to ensure that the clients are viewing it in a ICC compliant viewer so it displays correctly.

Of course, it's possible to get a beautiful image from the regular work flow, to each his own. I just think that many people make it or see it to be waaayyy more complicated than it needs to be. A couple of settings in the preferences and a couple of settings in the vray render settings and your off and running pretty much. I'm asked quite often to light and render other firms max models that already have textures applied. These are undoubtedly not setup for LWF or VRAY but inside of an hour or two I can have all of the materials setup for VRay and LWF by changing the preferences and adjusting the materials with a VRayColor or ColorCorrect Map (of course time depends on the scene size ).

[rmejia]

max default is not linear...it's sRGB that's the whole point. And regarding calibration anf gamma correction in an ideal world everything would be done linear and you'd have color profiles ONLY for outputting to any kind of device (like sRGB for your screen or some special profile, some printer profile for your printer etc etc).

By 3dsmax I meant the renderer, in this case VRay, sorry for the confusion. VRay is the one that calculates light in linear (gamma 1.0) but the result is displayed in a monitor with a gamma of 2.2 (or 1.8 on macs)

[beestee]

Personally, I use LWF on every project - interior and exterior and couldn't be more pleased with the results. My intent is to get better light and color distribution in the images. I don't however go the final step and do all of my post production in linear as Thorsten does. The advantages to keeping it linear are obvious but since most of my work is stills, and photoshop really doesn't support working linearly I usually just bake the gamma into the saved FB image. Yeah, I could use a linear profile (e.g., AIM RGB) in photoshop but I then have to ensure that the clients are viewing it in a ICC compliant viewer so it displays correctly.

Of course, it's possible to get a beautiful image from the regular work flow, to each his own. I just think that many people make it or see it to be waaayyy more complicated than it needs to be. A couple of settings in the preferences and a couple of settings in the vray render settings and your off and running pretty much. I'm asked quite often to light and render other firms max models that already have textures applied. These are undoubtedly not setup for LWF or VRAY but inside of an hour or two I can have all of the materials setup for VRay and LWF by changing the preferences and adjusting the materials with a VRayColor or ColorCorrect Map (of course time depends on the scene size ).

I concur with all of that

[paulison]

You can easily generate the correct gamma corrected color by using the vraycolor map and setting your gamma to 2.2 and entering the rgb values in the color color selector. Works every time.

Thanks, I wasn't sure if i should do it that way or by using colourcorrect map. I'll be sure to try that on my next project. I can usually get things close by approximation but occasionally clients do request slight tweaks because of my approach.

I tend to add more light or change colourmapping settings, the environmental light multiplier or secondary light bounces in order to get more light into shadowed areas. I know some of these methods make the render take more time than if i just used LWF but generally the result seems to look good for me. I think many people are mistakenly thinking that they NEED LWF to solve issues such as shadows being too dark when this isnt the case. For me, increasing gamma is just adding light to dark areas that isn't really there so the option of gamma 1.0 and increasing the light sources is the most accurate result IMHO.

I'm basing this on the assumption that raising the gamma has a larger impact on darker colours (as mentioned by others) since peoples 1.0gamma scenes generally have shadows that are a bit too strong.

anyway LWF/ RWF is just a gamma adjustment when it comes down to it. I generally do a slight gamma adjustment in photoshop anyway from 1.0 to about 1.2 which suits my own scene setups. So really to skip this process and consistently brighten my shadows slightly and add a few more shades of grey to the gradient, Maybe i'll start using gamma 1.2 PIWF!!

http://en.wikipedia.org/wiki/Gamma_correction

Reading this is quite helpful and does justify the need for a LWF. The thing that throws me off is the sRGB curve in this link. are we adding 2.2 gamma and not ending up with a correct image anyway?

[Shimakaze]

I'm basing this on the assumption that raising the gamma has a larger impact on darker colours (as mentioned by others) since peoples 1.0gamma scenes generally have shadows that are a bit too strong.

Sort of. LWF scenes do indeed affect shadows, but for a different reason.
When posting pictures on the internet they should always be in sRGB color space no matter what you're working in. If you post a picture in linear space it will look odd to people. too dark and such. LWF is a workflow. Not an end result in itself. Depending on where you take the image when it's done it will need gamma adjustment. And for the internet that means sRGB color space.
Things like "RWF" is really a misunderstanding because the whole idea of Linear workflow is to make input colors and textures behave realistically with lighting and such in the renderer (and compositing). It does not have anything to do with the gamma of the final image. "RWF" is basically LWF just with a slight gamma correction added at the end. Same as you would in Photoshop.

The thing that throws me off is the sRGB curve in this link. are we adding 2.2 gamma and not ending up with a correct image anyway?

No, the curve is correct
That's what separates "gamma" from a simple "brightness" operation. It doesn't alter all the colors equally but "shifts" the midtones up and down while keeping the dark and white point the same. In addition to that the gamma curve affects darks a bit more then brights.
You can try this yourself in Photoshop. For a simplified example, try opening the "levels" tool and shift the mid-tones. It works in a similar way except it affects darks and whites equally.
If you open "curves" and make a curve that looks similar to in the image it will have the same effect (though not as accurately) as doing a gamma correction.