All the works are rendered in ink and gouache watercolours on Fabriano Disegno paper and a series of small works have black backgrounds with objects such as a monarch chrysalis or an aluminium coffee pot looming out of the centres.
"I love working with inks and I've kept the colour palette very small with mostly blacks and browns."
There are limited prints of some of the works available and Williams' depiction of the "Welcome to Castlecliff" sign has been especially popular.
Meanwhile, Patrick Cush whose Salt to Scale exhibition is showing at Gallery 85 next door to the Rayners' gallery shows no restraint with his colour palette.
The artist says some of his densely layered oil on board works have layers of acrylic paint underneath.
"Some of these were works that I wasn't happy with so I've turned them into new ones."
Cush said all the works in the exhibition are recent ones and there are no hidden meanings behind the bright, abstract works.
"The title of the exhibition and the paintings don't really mean anything," he said.
"I get pleasure from painting them but it's up to others how they interpret them."
Originally from Wellington, Cush has lived in Whanganui since the late 1990s when he studied at the Quay School of the Arts.
Not Every Chapter Needs a Title ends on Sunday and Salt to Scale will be showing at 85 Glasgow St until August 3. Both galleries are open from 11am until 3pm, Wednesday to Saturday.