While out doing my digital full moonlight shoot I decided to bang off a roll of film. For this kind of thing I knew Provia 100f was the film for the job and I found an article talking about moon light exposures using 100 iso film and after some reading they recommended an exposure for around f8 @ 8min with a bit of an adjustment to make it about 9min 40 sec for Provia 100f. So taking this advice I shot off the whole roll with those settings and decided to do whats called a “Clip test” on the roll to see if it needs any kind of adjustment. I didnt expect it to be right but I did expect it to be in the ball park.
Well I spoke to the lab today and they said they did two clip tests one pushing the film one stop and another pushing the film two stops and it is still under exposed. Provia 100f has a push capability of two stops, but a three stop push isn’t recommended and from experience pushing three stops will blow the films DMAX and it comes out muddy. (tried that when I accidentally left the three stop ND on with a roll of velvia 50 and we pushed it three stops to get it back to 50iso… not good… not good at all). I am yet to see the Provia 100f clip tests to know how much I am off, or what I can or cannot see in them. Guess I will know tomorrow when the rest of my film comes back from the lab.
So on the next full moon what I will do is bracket. If I know a 9 min 40 sec exposure is totally crap and it is more than two stops under exposed I will start things off around 40 min and go from there. So I will do 40 min, 120 min and 240 min at f8. (Thats close too 7 hours of shooting for just three images). I had better make sure I have some good games on my iphone and a thermos of coffee. Or I might just use Provia 400x to save time. I’ll have to check into it’s Reciprocity rates.
For those who don’t know a clip test is, it’s something you do when you shoot the whole roll of film at a single exposure setting and aperture. Thinking you have the right exposure but your not 100% sure. At the lab they will cut off a small part of the film and process it at “Normal” which is the films iso speed. From there they will examine the film and determine if the films exposure needs adjustment to make it correctly exposed. If so they will do the adjustment and you will get the remainder of your film perfectly exposed. Any adjustment is of course only capable depending on how close you are to correct exposure and the films push / pull capability.
For example Provia 100f can be shot at film speeds of 50 iso (1 stop pull) or 200 / 400 iso (1 & 2 stop push). So if your film is off by two stop under exposed or one stop over exposed it can be corrected.
Isn’t making mistakes and learning fun !!