How To Add Color To A Object In A Black & White Halftone Image

[PixLab]

Depending the result you are searching for, may be try:
Duplicate your image in the layer stack
Bottom image make your halftone Black and white

   

Then on the top image make your halftone in color ➤ Look a t the setting of the filter

   

Then on the top layer put a Mask ➤ Black , then  paint in white on the belt part