Three compact powerful radio galaxies were imaged in B and I colours. Two of these galaxies, PKS 1814-637 and PKS 1934- 638 have colours bluer than gE galaxies; PKS 1353-341 has normal colours: it is a very luminous cD galaxy.
In all three sources H I absorption has been detected. The optical depth are 0.12, 0.21, 0.002 respectively for PKS 1353- 341, PKS 1814-637 and PKS 1934-638.
We find that in PKS 1353-341 the torus or disk in which the absorption takes place should have a radius of tens of pc.
From our results and a search in the literature, we conclude that powerful radio galaxies tend to have a high probability to show H I absorption.
However, we could not determine if the H I is falling in towards the nucleus or if it flows out, because of the difficulty in determining the systemic velocities of the galaxies.