I want to say right from the get go that this topic can expand to minutia and I will not go into it too deap. In general, from time to time I do critiques for artists online and within those topics comes out interesting topics that really should be shared with a vast majority of artists.
I asked Corey Hill if I could use his work as an example for the topic. Thanks for his openness on this. You can check out his ArtStation here. He has been working really hard and keeps on doing amazing environments and tweaking as he goes.
The topic of textures values is not only for physically base renders, but it has become far more important with PBR of course.
When artists are making textures for an environment you will need to be conscious of what lighting conditions will be around. In general, a rule of thumb is to make sure textures are not too dark. But just saying that alone will only confuse. The biggest reason environments should not have dark textures is that in the physical world very few materials go below a 50% gray scale value. Materials that would go beyond that would be plastics, certain rocks, and paints. It is also the opposite the world has less material that are super bright usually super bright textures would be reserved for paint, metals, and others. So as an artist when working on environments before PBR I tend to stay in the 50% grayscale mark or higher. With PBR I actually tend to stay above that and move my median around 40% – 30%, so much lighter in general and the reason is that I rather have a brighter texture that causes too much bounce vs a texture that is draining the life out of my scenes. You still want to maintain interest so making everything harmonies 100% will not likely be the best bet either. So at the end it really becomes an artistic balance that needs to be had from materials and lighting.
Corey Hill’s work recently has improved a lot and you can clearly see he is pushing forward to learn new techniques. I asked permission if I could use his two environments the Bar and the Bedroom. Both have issues when it comes to values and also lighting. But before you can fix lighting in this case I would say you need to fix the value of the textures.
This is a shot of a bar area in which from the get go we see that it is too dark. So the first instinct would be to tweak the lighting.
To get the pass below to only see the albedo view first Corey found the texture only view than I made it gray scale in Photoshop.
Right from the get go we can see that most of the scene is either below 50% gray and a large portion is really bright, the ceiling. (oh pointing out the screenspace ao is still on in this view which causes some darkening in spots still fine to use as a debug image)
To visualize better I put this screenshot together which should help illustrate.
You can see I have three colors Red, Yellowish, and Blue. From the gray values I placed colors representing anything below 50% gray I was a little lenient on this one since most textures should be pretty dark including the brick. but I think this scene could really use some value shifts to add interest and bringing up the scene entirely up a bit would do wonders. The ceiling is also too bright and can go down a good bit. The chairs backrest is really close value wise to the counter so it is slightly getting lost, this would be a tweak to brighten the chair backing and add a tiny bit of saturation. The scene it self could use a bit more variation in color it feels pretty monochrome.
looking at the image below you can see that most of the scene is at or below 50% and has some bright spots also leaving the top range almost untouched.
From Unreal Wiki Below
Here is an explanation on the Unreal Wiki literally copy paste read more linked here
“Here is an example of a texture that was too dark and saturated compared to how bright it should be.”
“The original texture’s values averaged at 46, which means when converted to linear space they would only bounce 2% of light! The adjusted textures average value is 150 which means it’ll bounce 31% of incoming light which is decent for a brick wall. The adjusted texture will also show shading better since there’s much more of a difference between it being fully lit and fully shadowed.”
“Below is a practical example of how dark textures affect lighting. The top image is using the original dark texture. The 2nd image is trying to fix the image brightness by increasing light intensity from 2 to 12. You can see this doesn’t help GI or the dark areas at all. The final image is using the adjusted texture with a light brightness back at 2. These images show that if the textures are too dark they will not result in good lighting no matter how much you try to fix it with brighter lights.”
So now moving onto the bedroom here we can see a super interesting, but insanely dark room.
I love all the small details and besides some slight normal map issues on the wood floor grain and pillows this could make for a very sweet scene. Again the first instinct would be to increase the intensity of the lights.
Again gray scale view of just textures. This one clearly has very dark texture values.
Viewing the below you can see that 80% of the room is well below 50% grayscale. The two brightest spots are the light bulb and the ceiling. This scene is in heavy need of bring up the texture values all over. We are losing tons of great details by the textures which is causing a super contrasted scene do to how dark it is and how bright the ceiling is. I think this scene could actually be one of Corey’s best scenes due to all the small story telling if more time is spent on values and lighting.
Thanks to Corey for allowing me to do this. You are awesome and willing to open yourself up for possible critique is great!
Since Corey Hill was asked for permission I will help him a bit and then we can return here for part 2 hopefully more or less showing the changes done.
Other Great reads on topics alike to this…