White Pass--Blender is *SO COOL*

Now I learn that the smart way to analyze lighting is to paint everything white, adjust lights in the white scene/room, and when everything’s happy, then texture and color all the surfaces. Seemed to me that a wicked cool feature for the renderer would be a “white pass” that allows the choice of “white” material (selected from the material browser) and then replaces all non-transparent materials/textures with “white”. Lo, the feature exists: just write in the white material in the Render Layers tab of the Render Panel where it says "Mat: ". SO COOL!

that is cool. thanks for the insight, i had been wondering about such a feature myself. : )

jim ww

Thanks for the tip! Your brains have been codified into the wiki http://wiki.blender.org/index.php/Manual/Lighting#Introduction

I just thought of this but don’t have time to create the .blend file example. Using the node system, it should be possible to put a “zebra” exposure meter in the camera. Create a series of diagonal lines alternating in black and white (the zebra). Feed the luminousity output from the rendered image to a key such that when exposure is 80%-90% of pure white, you get the zebra pattern, and otherwise you get the original image. Where the exposure is > 90%, it will be basically white from the image. In this way, you can find where the exposure hotspots are in your images (just like if you are using a pro-grade video camera).

While I would certainly agree the material override is an awesome feature, I’m not sure I’d agree that setting everything to white is the way to do lighting. There are no one size fits all lighting solutions, and the colour of the materials in the scene are going to play a large part in the final appearance. Unless you want something totally clinical (well perhaps for architectural work it would be ok), I think it’s best to take advantage of Blender’s integrated approach and use the tools (materials, lighting, compositing) in tandem to arrive at a final result.

It’s basic colour theory that colours will react differently and look differently depending on their environment, what other colours are around. You get light absorbing different colours and reflecting colours off surfaces when it bounces. The colours you use are also going to be dependent on what kind of mood or expression or compositional focus you want to create, and it’s very hard to do this in a vacuum, one step at a time.

I have made a simple nodesetup, to get informations about the white balance in the scene.Hit F12, render and then move the sliders of the color Ramp. You`ll get a quick and interaktive feedback of bright and dark areas in the scene.


You can do this via the value slider form an HSV node and a map value node. As you can see only the blown out highlights are visible via this setup. I’m not sure how you’d go about it for precision but as far as aesthetics go, this setup works quite well.


I must be missing something. Why do this? Why make everything white, are you trying to bleed everything out to see if lighting is correct? Good thing we don’t have GI in this case.

yes, master. Just to look for overlighting that is washing out colors, underlighting where more light is wanted, playing with shadows and where they fall, that sort of thing