Brush on sensitizer or dip items in sensitizer. Tape negatives to three dimensional objects that won't fit under glass for exposure. A for one minute with agitation Take out and rinse in water Place print in solution B for about 30 seconds with agitation Rinse again in water Place print back in solution A, agitate until it turns purply brown Wash a few minutes and dry. There are some commercial blueprint papers that have a light sensitive emulsion and can be exposed to sunlight, arc light, blueprint machine, sun lamp, and so on, and then are developed in ammonia fumes. Commercial blueprint paper is usually direct, positive paper, since it is made for copying blueprints as positive images.
Longer exposures give lighter images and short exposures give dark images.
This type of paper can be found at blueprint or printers' supply companies. Commercial blueprint paper is usually fairly fast and may only need exposures of less than a minute, even a few seconds, depending on light source and negative density. As always, make some small test exposures first. Household ammonia will do, and industrial strength ammonia works better but is more hazardous to handle. This kind of paper fades in light.