converting image sequence

Dear Sirs,

when I convert image sequence into a ProRes 4444 + Alpha using Compressor i noticed a difference in brightness with the original content.

This happens every time i elaborate in After Effect a special effect.

The images in output from AF are identical to the original, after the conversion there is this difference.

I tried to create a custom ProRes 4444 + Alpha setting changing to "none" the gamma conversion into the Quick Time settings panel, nothing changes.

Can you help me to find the right solution?

thank you

Aldo