I'm trying to take pictures of some flat metal parts that have serial numbers engraved in them. The goal is to generate life-size transparencies that can be overlaid on actual parts to verify the position of the serial numbers (I work on the tools that put the numbers on the parts). I already tried scanning one of the parts on a scanner, but the numbers don't show up--you have to use a particular angle of light to get the serial numbers to reflect back.
So far I'm shooting onto Arista II ortho litho in a 4x5 camera to fill the film. Then, I put the negative into my enlarger and adjust it to life-size, using one of the actual parts to get the magnification right. Then, I print onto an 8x10 piece of ortho litho, and contact print that to a 3rd sheet to make as many semi-disposable transparencies as needed.
It's working fairly well except I'm having trouble exposing and developing the film. I don't have special developer for it so I'm using Dektol diluted 1+2 with water. When I hold the transparencies up to the light, the dark areas are mottled and streaked, even when I try to agitate well in the developer tray. I'm thinking about either trying brush development or film developer instead of paper developer. I'm also not sure if I should leave it in the developer a 'long time' and develop it to completion, or if I should try to time the development. Right now I'm driving myself crazy adjusting the exposure and the development time both, trying to get something that works...
In principle I don't need to use orthro litho film--I might try TMX for the camera part--but ortho litho makes sense for the final transparencies because it's cheap and the 'ortho' part makes it easy to work with. I think this film has an intended purpose for burning offset plates for printing, but I'm to young to ever have used it for that and don't know anyone else who even knows how to use film anymore...
Reply With Quote
Bookmarks