Density Readings from FP4 negatives in Pyrocat-HD using a spotmeter

[helios1014]

Hello All,

I am trying to figure out my negative densities for Zone system useage. My developer is pyrocat-HD, the tempeture is 70 degrees, I am developing the sheets in a nikkor stainless steel 4x5 tank, and I went with the Massive Dev chart time of 20 Minutes for an exposure at 125 ISO. Using a Sekonic L-228 spot meter, I read the side of my house as EV 17 with f16 at 500 as the recommended exposure. Using that basis, I shot the following exposures:



Sheet #
F stop
Speed
Zone


1
16
1/25
I


2
16.5
1/25
I


3
11.5
1/25
I


4
11
1/25
I


5
45
1/400
VIII


6
45
1/200
VIII



From those negatives, I arrived at the following meter readings and densities (1/3 stop equal .1 density) by placing the negatives on a window and reading the light through them:



Sheet
Sky EV
EV Through film
Calculated Density


B+F
15
14 2/3
.1


1
15
7 2/3
1.8


2
15
8 1/3
1.7


3
15
8 2/3
1.6


4
13 1/3
~8 1/3
1.2


5
15
11 1/3
.8


6
15
10 2/3
1.0




Now the Zone I negatives are showing a rather high density as I have read that one should expect a density between .08 and .11. Am I missing something in my calculations or might I have developed them in correctly or is the pyrocat adding apparent density I have to account for?

Unfortunately I cannot afford a densitomiter at this time, nor do I have a local lab to ask so this is the best I have for checking density.

[Andrew Tymon]

Twenty minutes seems like a long development time. Here is Sandy kings recommended times for pyrocat.http://www.pyrocat-hd.com/html/times.html

[Jim Noel]

I agree- 20 minutes @ 70 deg should run the highlights through the roof. I am not sure that reading the densities via a spot meter has any accuracy.

[esearing]

Twenty minutes seems like a long development time. Here is Sandy kings recommended times for pyrocat.http://www.pyrocat-hd.com/html/times.html

I disagree - Depends on dilution and agitation technique - My normal is 24:30 - 26 for FP4+@100.

Accuracy/consistency of shutter has to be accounted for. You might be better off putting a step wedge in front of your film , meter and open 5 stops where fstop and speed is consistent on your shutter. Develop and measure negative , adjust processing time +or-20% for 2nd sheet , repeat. Then contact print to see differences on paper. This will also help with your personal bias regarding negative contrast, some like them contrasty, others prefer them flatter. Print vs scan comes into play too, as well as choices of chemistry and paper if printing wet, and all the variables associated with your process end to end. A final print is the result of choices made at each step and is what makes photography both fun and frustrating.

[David Schaller]

My normal for FP4 at 100 in Pyrocat 1:1:100 is 10-11minutes, in tanks and trays, for silver printing.

[Andrew Tymon]

I disagree - Depends on dilution and agitation technique - My normal is 24:30 - 26 for FP4+@100.

Accuracy/consistency of shutter has to be accounted for. You might be better off putting a step wedge in front of your film , meter and open 5 stops where fstop and speed is consistent on your shutter. Develop and measure negative , adjust processing time +or-20% for 2nd sheet , repeat. Then contact print to see differences on paper. This will also help with your personal bias regarding negative contrast, some like them contrasty, others prefer them flatter. Print vs scan comes into play too, as well as choices of chemistry and paper if printing wet, and all the variables associated with your process end to end. A final print is the result of choices made at each step and is what makes photography both fun and frustrating.

I was assuming the op was using standard dilution of 1:1:100 if you use 1.5:1:187 well obviously your time will be longer.

[helios1014]

I was assuming the op was using standard dilution of 1:1:100 if you use 1.5:1:187 well obviously your time will be longer.

My dilution was 1:1:100. I did order a shutter tester but the mail is being slow in that one. Could I be doing the math wrong on the density calculations? My assumption is that the change in EV from unexposed light is the density of the negative.

[Bernard_L]

First off, something's wrong with your Zone assignment

Sheet # F stop Speed Zone
1 16 1/25 I
2 16.5 1/25 I
3 11.5 1/25 I
4 11 1/25 I
5 45 1/400 VIII
6 45 1/200 VIII
f/45 1/400 is a lot less exposure than f/16 1/25. So the former cannot be Z_VIII whith the latter being Z_I.

Second,

I read the side of my house as EV 17 with f16 at 500 as the recommended exposure.
If f/16 1/500 is the recommended exposure (landing in zone V) then f/16 1/25 is 4 stops more, i.e. Zone IX.
And f/45 1/400 (at this stage of discussion, disregard the difference between 1/400 and 1/500) is 3 stops less, i.e. Z III.

Strange everybody so far commented only on dev time. You should clear up that zone thing before proceeding with sensitometry. Or just shoot your FP4 at 80 speed; don't fear to hit the shoulder with FP4. And bring the images home.

[Bill Burk]

Your Zone I should have been 1/400 at f/90 given 125 speed EV17

You placed exposure at Zone X

At least this is a good development time test.

(Or IX as Bernard_L noted)

[helios1014]

Your Zone I should have been 1/400 at f/90 given 125 speed EV17

You placed exposure at Zone X

At least this is a good development time test.

(Or IX as Bernard_L noted)

I suspected I might have over exposed those negatives. Thank you. Thankfully I bought a 100 sheet box of film.