Messages

1

[Max] I need help! / Re: Color accuracy

« on: 2025-03-18, 14:11:47 »

This post warms my heart - really, good to read it drives others mad, too.

Two in-depth articles from a longtime Max user about PBR and some of its assumptions and pitfalls, and practical solutions:
https://www.racoon-artworks.de/blog_PBRfromrulestomeasurements.php
https://www.racoon-artworks.de/blog_PBRshootingandcalibrating.php

Getting the right material properties is hard without a proper device. A colorimeter will only give you a reflected color value without any other info about reflectance and its behavior. The there's the materials surface which will affect all incoming/outgoing light and will produce different results for lighting and viewing angles.

Then there's the renderer - you can't really be sure how realistic it'll model the reflectance behavior when it comes to surface structure, how bump maps work in renderers is generally very simplified and will not reproduce real life accurately, and with texture filtering you can not really tell what it'll do). Rough diffuse materials are really a topic on its own with hardly any renderer caring about it.

As for sRGB, it's only getting worse from here. I'd say the range of colors in RAL and Pantone that can't be reproduced in sRGB may even be about 50%, maybe even more. I have not once come across a site that will tell you which space of RGB they assume for the values, and I'm pretty sure it's because they know it's impossible and just tell you a number close enough. Some vendors will give you LAB colors which is another can of worms because the scientific LAB space is not the LAB you'll find in Photoshop.

Broad topic, and then there are clients who will view your results on an uncalibrated display one day and tell you it's too dark, and the next they'll look at it on their mobile and tell you it's too bright and could be less saturated :D

I have worked in pre-press for some years and looking back I wish people in all places of the production chain (software vendors, too) would care about this today as people did 20 years ago when they printed stuff on paper.

Great information! Ive gone searching myself a little more and found this page on polyhaven saying similar things. Awesome stuff! Aparently lightroom is garbage for this type of work because it's geared towards non-technical people and a lot of stuff that significantly influences the final output is hidden away or automated.

https://docs.polyhaven.com/en/technical-standards/texture-color-calibration

2

[Max] I need help! / Color accuracy

« on: 2025-03-14, 10:48:02 »

I can't wrap my head around this.

I've always wanted to create realistic materials in 3D. My approach is simple: if I reproduce every real-world value—light intensity, camera settings, and material colors—as accurately as possible using measured data instead of "eyeballing," then theoretically, the render should look as realistic as possible.

I can manually tweak values to make something look good—that’s not the issue. The real problem arises when working with clients. I want to establish a workflow where I can rely on measured, objective data instead of subjective adjustments.

If I’m not mistaken, not every Pantone or RAL color fits within the sRGB color space. This would mean that some real-world colors cannot be accurately represented in 3D since the base color input for most physically based rendering (PBR) workflows assumes an sRGB format. Additionally, there are many websites that claim to convert RAL to rgb (what i assume is gamma corrected srgb, even though it doesnt say ANYWHERE?) but they dont list how this is measured at all. Is this done scientifically by the makers of ral or pantone? or is it a kid in his bedroom guessing the rgb values by eye on a decently calibrated monitor? I guess we'll never know.... Please give me reliable sources someone...

This leads to my main question:
How do you accurately measure and input real-world colors into a 3D material?

If I have a plastic sample or a painted surface with a specific color, can I use a color meter to measure its sRGB value? And if the measured color falls outside the sRGB gamut, does it simply get clipped? If so, how do professionals handle this issue?

I'm not overly concerned about color clipping itself. My bigger frustration is the lack of reliable, standardized guidance on achieving accurate, repeatable results. I want to build materials using real-world values and then control my renders in the same way a photographer would—by adjusting lighting, exposure, and composition.

I do have an X-Rite ColorChecker at work, but it seems to correct colors relative to white balance rather than providing absolute brightness measurements. What I really need is a way to measure a real-world color, input it into a shader, and trust 100% that the result is scientifically correct. If the render looks bad, it should be because of poor lighting, exposure, or composition—not because the material itself was guessed.

I’m tired of pulling values randomly until someone arbitrarily decides "this looks good." That’s not accuracy—that’s just subjective tweaking.

Are there any experts in this field? Where can I find proper guidance on this?

3

[Max] I need help! / Re: Image Editing tonemapping error.

« on: 2024-09-16, 07:58:57 »

I had the same issue but it has vanished slowly by itself over time. I suspect the new VFB in corona has some changes that werent properly pushed through to the image editor (i.e. the image editor didnt get a proper update eventhough the vfb in the renderer did causing some small incompatibility)
I'm just speculating here though.

4

[Max] I need help! / DR Not working on a specific scene

« on: 2022-09-01, 11:20:10 »

Hello, we are trying to render a production scene using DR
We have used DR succesfully in the past but for some reason we can not get it to work on this scene.
I have taken a look at the logs and realized very quickly I an not tech savvy enough to see what is what and what is causing the issue.

We have tried the following:
Removed all the Anima4d assets from the scene (I saw an error in the console about anima and thought this might fix it. it fixed the error but the same issue was still present.
Rendering a still instead of an animation
Using pathtracing as seccondary solver instead of 4k cache

We have tried using the same DR rendering setup with different scenes and that worked perfectly. So it has to be something with this particular scene for sure. Probably something with a license, or an object thats corrupt in some way..
We've already pushed the deadline back for this project so there is not much time pressure luckily.

Thanks in advance

~ Max from Virtual Builders