- Joined
- Aug 16, 2016
- Messages
- 251
Yesterday after watching Martin's video on the film and development cycle I decide to have a try myself using a couple of old folders I have. I used Fomapan 100 rated at 80 ISO and measured with a Profisix Light Meter in incident mode. That gave me 2 seconds exposure at f22. Looking at the reciprocity chart for the film that translated to 6 seconds. As there was a degree of Bellows extension I used Keith Haithwaite's formula to determinate that correction. My lens was a 150mm and the extended bellows measured 220mm. I calculated the factor to be 2.15. Multiplying the 6 seconds by 2.15 I gave 13 seconds exposure. I have just developed the first negatives and they are THIN. So the question is should I have applied the bellows factor first then calculated the reciprocity or did I do it in the right order? For the last frame I took a "check shot" out of the window and that is fine. If I had done the bellows before reciprocity the exposure would have been 23 seconds. According to the reciprocity chart 4 seconds would increase to 19 and 5 seconds to 27 so 2x2.15 is near enough to 4.5. I would have based my time on an average between 19 and 27, 23 seconds.
Any thoughts?
I should say I am a film/darkroom only person and have plenty of experience developing film but not a lot with long exposures like this.
Thanks
Bill
Any thoughts?
I should say I am a film/darkroom only person and have plenty of experience developing film but not a lot with long exposures like this.
Thanks
Bill