Why does a black background ruin the neon effect?

[Zsombor28347664zzs9]

I made a neon effect rectangle in Illustrator and I want to use it on a black background, but when I drag it to the foreground, the effect completely crashes and becomes a terrible white color, but I don't know why.

I will attach a picture of it.

I made this based on this video: https://www.youtube.com/watch?v=qsu9yP1lVBM

Thank you for your help in advance.

[Mylenium · Accepted solution]

This looks liek you created your document in CMYK mode, not RGB. This will of course affect belnding modes and transparency operations and parameters may need to be tweaked differently.

Mylenium

[Zsombor28347664zzs9]

Oh really. Thank you very much for your quick answer. 😄