I'm using PPG HPE400 epoxy primer ( see, sometimes we listen

) , brushing it on to the repaired areas as I go.
Now I ended up with the white activator (401?) so the result is grey, it was all I could find.
I would love to have a black primer (the car is black).
Can I tint the epoxy? The sheet makes no mention. The sheet for DLP says explicitly not to tint, I don't know how similar they are.
If I don't stir the solids in the activator it comes out darker, are the solids integral to the cure or composition? Seems to harden the same?
Thanks
Dave