Quote Originally Posted by Tom1956 View Post
... So lets start with straight D-76 in a tray ... I'm thinking find a development starting time first, then move on to finding a film speed. Starting with what I might know as a standard, is that I BELIEVE film speed will be 80-100 range. ....
As an engineer I felt compelled to go through a similar path (step wedges, density tests, varied development) for several of my favorite films about 20-25 years ago. It was an interesting learning experience but I would not recommend it in this case. X-ray film is not designed to give you a conventional rendition so a more pragmatic approach should serve you better:

1. Shoot five frames of a normal scene at different ISO values +/-2 steps from the suggested ISO (about 100) and develop for the suggested time. Pick the ISO that results in the most satisfactory shadow detail. Remember that this is orthochromatic film so the shadows will be lighter in daylight. Development time should not affect the shadow detail much.

2. Using the ISO for the shadow detail you favor, shoot the same scene in the same light and develop for the recommended time and +/-20 and 40%. Dilute the developer for all cases if any of these times is less than about 5 minutes. Select the development time that gives you the most pleasing rendition and that is easy to print or scan.

This should give you a reasonable place to start and you will not be disappointed like you might be when you transfer your carefully calculated sensitometry test into the world of reality.

All of this can be accomplished with ten exposures. You can always tweak you ISO and development later based on your experience with scenes you normally shoot.