I was intrigued to see what the Derive HDR from LDR material node does. I’ve seen it in Paragon assets but never really looked into it or understood what it does. So I setup a very simple test to see the differences.
I started by setting up a standard emissive material that is typically used.
I then created another material using a simple DeriveHDRfromLDR node
I then created a particle system with 2 emitters side by side. 1 for HDR and 1 for LDR. Both emitters use exactly the same values. I then assigned the different materials to each.
The results:
Be careful when using this to not boost your colour values too much or things start to break (although…kinda looks cool too, depending on what you’re trying to achieve 
)
Instead, increase the HDR Intensity in the Material to boost values. This could be hooked up to a dynamic parameter and controlled via the Particle System if you wish.
Thought this might be useful for anyone else interested in this. Would love to know more if anyone else has further information on this 