brucemcelya
25-Aug-2008, 17:39
Friends,
Re: Steve Simmons article in View Camera about film speed and development time.
The article is a basic primer matching a film to a paper. It is well explained and understood, but I have a problem. It is a rare day here in bluegrass country when the sun shines through a clear sky. Mostly the light changes by the minute with off-and-on cloud cover. To run the tests properly means changing f stops by a quarter to a half stop amid unchanging light. I've tried for a number of days and can't seem to get consistent light when I need it, even in the shade, so the test was set up inside with lights against a nice piece of smooth cardboard shot way out of focus (lens at infinity). Once the sun goes down and light no longer enters windows, luminance doesn't change. Great.
Question: Will shooting under quartz light (3200k) against a light brown board, using daylight balanced film throw off the test? Use a gray card? White card?
Particulars: Pentax analog spotmeter, not modified. Tmax100, TXP320, D-76 1:1
Jobo cpp2 processor, 500 ml developer per six sheets film (4x5),
Berrger CB Art #2. Proof print time from base+fog negative based on two
minutes in zone six paper developer, with five minutes selenium tone @
1:20.
I ran the TXP film speed test and the difference in opacity between exposed half of the negatives is discernible all the way through, though I haven't put it to the paper yet. I would like to avoid a bunch of do-overs if possible. If you have some ideas, need further information, or see any red flags from above, I would like to hear. I have not run the tmax100/D-76 film speed test yet. I seem to remember something in the far past about a correction in b&w about using quartz, but can't pull up the details...... If using quartz light is legitimate, I'll continue on.
Kind thanks,
Bruce McElya
Re: Steve Simmons article in View Camera about film speed and development time.
The article is a basic primer matching a film to a paper. It is well explained and understood, but I have a problem. It is a rare day here in bluegrass country when the sun shines through a clear sky. Mostly the light changes by the minute with off-and-on cloud cover. To run the tests properly means changing f stops by a quarter to a half stop amid unchanging light. I've tried for a number of days and can't seem to get consistent light when I need it, even in the shade, so the test was set up inside with lights against a nice piece of smooth cardboard shot way out of focus (lens at infinity). Once the sun goes down and light no longer enters windows, luminance doesn't change. Great.
Question: Will shooting under quartz light (3200k) against a light brown board, using daylight balanced film throw off the test? Use a gray card? White card?
Particulars: Pentax analog spotmeter, not modified. Tmax100, TXP320, D-76 1:1
Jobo cpp2 processor, 500 ml developer per six sheets film (4x5),
Berrger CB Art #2. Proof print time from base+fog negative based on two
minutes in zone six paper developer, with five minutes selenium tone @
1:20.
I ran the TXP film speed test and the difference in opacity between exposed half of the negatives is discernible all the way through, though I haven't put it to the paper yet. I would like to avoid a bunch of do-overs if possible. If you have some ideas, need further information, or see any red flags from above, I would like to hear. I have not run the tmax100/D-76 film speed test yet. I seem to remember something in the far past about a correction in b&w about using quartz, but can't pull up the details...... If using quartz light is legitimate, I'll continue on.
Kind thanks,
Bruce McElya