Cool image of the Holy Trinity from Belmont Abbey.

Note the triangular composition set in an oval nimbus.
The Father in absolute white to indicate his total purity and divine essence. One hand raised in blessing. The other holding a scepter.

Christ the Son to the right hand of the Father. You can see the nail prints in his hands. One hand receiving all things from the Father. The other hand giving all things to the Holy Spirit

The Holy Spirit in Pentecostal red, pointing with one hand to the dove on his breast, and with the other hand pointing to the earth below–where he will be sent.