Blackbody node - something ain't right

I have a Circle mesh with a 1 N-Gon face. It’s shader is Emissive and a Blackbody node supplies the color. All other lights are Off. (2.93 Eevee)

Here is my result for 1,700K.

It just don’t look the same. Where have I gone astray?

1700K

Thanks
Cal

Are you using Standard or Filmic color transform? Use Standard, that washed out orange you’re seeing looks like a classic Filmic thing to me. It’s in the Render tab of the Properties, towards the bottom, drop-down that says Color Management :slight_smile:

Also- how strong is your emission?

Emission Strength: 1.0

Tried Standard… looks even more worse, different.

I don’t recall anyone ever mentioning the Blackbody node in this forum. Maybe this is why.

Hmm… I wonder if it works better on cycles?
I know for sure it works better at higher emissive strengths (and with Bloom turned on), I’ve used it for fire before with good results, but that was closer to 15 or 20 emission strength :thinking:


image

Use it with a light. To match a real reference you need to consider white balance from camera that was shot, and tweak manually. For emissive shader isn’t that accurate, yet strenght values higher than 10, will work as you already used.

0.2 meters light, 3500K at 60W:

Proper scaling and light size also need to be considered.

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To the best of my knowledge, blackbody doesn’t work in Eevee. Dunno why, it just doesn’t. :man_shrugging:

That being said, the last time I really tried checking was in Blender 2.93 or so, and I don’t know if this has been “fixed” in Blender 3.0 and newer.

One problem with the inbuilt black body node is that it’s output isn’t normalised in the 0-1 range. That means you can get RGB values above 1 if using it to convert temperature to colour which can cause issues and colours wont necessarily appear a you might expect.

It also doesn’t cover the full range of colour temperatures - topping out at 12,000K.

I created a new black body node a while back to correct these issues - you can download it from blendswap.

https://blendswap.com/blend/12064

I also made a second node that also includes a brightness output based on Plancks law

https://blendswap.com/blend/12214

I used the temperature to RGB tables below to make the nodes above - hopefully you should find their output a bit more consistent.

http://www.vendian.org/mncharity/dir3/blackbody/UnstableURLs/bbr_color.html

Right. Forgot to mention, test I did was Cycles. There’s a scientific study converting temperature to RGB values that may be used in Eevee, yet won’t achieve that lamps picture realism.

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This will get me close enough for the stuff I create:
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