I have Xrayed boards to find shorts/opens on BGA packages but never used X-ray film for negatives. I have used Ilford Ortho film to make contact positives for exposing photoresist coated board. Almost any film should work and I see no reason why Xray film would not work just fine. The only issue would be the film speed. Normal graphics ortho film is failry slow acting with good contrast for nice dark images. I would think Xray film is also going to be orthographic but with a much faster speed to keep the Xray radiation exposure short. Based on a few dental Xrays I have seen, the contrast should be fine but you will have to play with the exposure duration and light intensity. Give it a try and let us know how it works out.
I still have about 75 sheets of Ilford ortho film that I purchased 30 years ago. One of these day I will have to see if it still works. Recently went looking for some new film but in the new digital camera age most of the B&W film manufacturers have quit making silver halide film and most all the camera/dark room stores have gone under. What I did find was much higher in price (cost of silver?)at about $1.00 per sheet.
If you search the web, there are still a few folks doing B&W view camera work. The alternative is a sepia process which is not silver based and developed in ammonia vapor, however I have not had any luck finding an 8x10 sepia film source.
Craig
--- In Homebrew_PCBs@yahoogroups.com, "musick7@..." <musick7@...> wrote:
>
> Could this be done? Could Xray paper/Film be used to make a Negative for a double sided PCB?
>
> I've got access to an XRay developer machine and was wondering about this... The Film is pretty large so If at all possible I could make a PCB 1' by 1'
> or bigger but thats the biggest size of paper we got...
>
> Just a thought... Whats everyone Think?
>