Film Development Test for Black and White Large Format (4x5) Ilford FP4+

Introduction

I want to start fresh on my Black and White photography. This is part of my effort improve in all areas of my photography.  In this post I want to concentrate on large format film exposure and developing. I want to follow a zone based system of exposure and development that utilizes my spot meter (as that is the meter I will mostly use) my choice of medium speed Black and White film (Ilford FP4+) and single shot developer (Kodak HC-110).

My rationale for single shot developer and choice of HC-110 is laid out in this previous post.

First I need to create a zone-based test pattern. I reasoned that if I could do this all in camera it would be cheaper and easier than using a specific target. The methodology I figured out on my own though I doubt I am the first to think of it.

The methodology is to aim the camera on an artificially lit uniform surface of uniform brightness. I then use the darkslide to progressively expose the entire sheet of film. I do this using the zone scale for my desire ISO of the film (I will choose 100 ASA though the box rating of FP4+ is 125). If I do this properly I will have a single stripe of even exposure per zone as well as the film base.

With the film exposed (but not developed) in these stripes I plan to cut it into 3 strips perpendicular to the exposure zones. Each of these will be developed separately in my single shot developer at -20% time, nominal time, and +20% developer time. This should allow me to establish my best nominal development time. This alone is a useful task and data point and one could stop here. This is very similar to what I did in an earlier post based on suggestions from Andrew Sanderson.

However I will proceed further as I want to establish my +/-N developing times to complete the zone process. In the zone system one pushes or pulls the development to increase or decrease the contrast to compensate for the contrast inherent in the scene. This is most suitable for large format as each image can be developed individually. Something that is not possible in roll film.

The Test Strip Mechanics

As mentioned in the introduction the test strip is constructed by pointing the camera at a constantly lit evenly colored (white) surface. I plan to use my longest lens as a wide angle can be subject to vignetting which could disturb the results.

Next I use the dark slide to divide the film into 12 strips, 11 zones plus the film base (unexposed). The film base is crucial to the densitometry measurements as every density must be referenced to the film base. 4x5 film is about 127mm on the long axis that the dark slide moves along so dividing that by 12 I can use 10mm per zone.

So I setup the dark slide by marking my 10mm lengths on it. For me I had found this cool tape that is marked out in mm increments that makes the task easier. One could also use a ruler to make the same markings on a piece of tape or the darkslide itself. If you use tape I recommend it is very thin to not interfere with the light seal. (My tape is like mylar packing tape.) I also recommend you wrap the end of the tape around the end of the darkslide as the light seal tends to peel up the tape when inserted otherwise. Below is what my dark slide looks like...

Figure 1. Darkslide with mm increments marked off.

Figure 2. Darkslide inserted but film area fully visible (51). 

Figure 3. This is the position for the first exposure where the first 10mm covers what will be the film base (52). 

Figure 4. Final position of the darkslide for final 10mm exposed strip (darkest) (62)

Calculating Zone Strip Exposures 

The next step is to figure out the exposures for each zone strip.  I start with the assumption I will use the shutter speed to vary the exposure and keep the aperture mostly constant. I chose to vary shutter speeds as there are more shutter speeds than apertures limiting the number of different combinations needed. I built a table to help with the calculations. Since the darkslide is used, the exposure accumulates like a test strip in the darkroom. That is to say the last strip is the sum of all the previous exposure times and its own.
Zone V sits at 1/30 of a second and the aperture must be set for a nominal zone V exposure for the selected film speed. For zone V exposure this is the same as the meter gives normally. I used a spot meter but any incident light meter should work as long as its field of view only 'sees' the uniformly lit portion of the wall.. Set the meter for the film speed (in this case 100 ASA) and the shutter speed for 1/30th of a second. measure the incident light of the uniformly lit surface and take a measurement. The aperture is what we are after for the 1/30th of a second shutter speed.

Once the aperture is selected for this then it is used throughout except for the first 2 exposures which have to be at one stop higher as I don't have 1/1000 sec shutter speed. So if the zone V exposure is f11 at 1/30th then the first 2 exposures need to be at f16 then the rest at f11.

The table below shows the calculations.

• The darkslide row shows the insertion depth of the dark slide. 
• The Zone row shows which zone is being exposed. The first column indicates this is not exposed as it the film base. Zone V is highlighted. 
• Multiplier is a figure I use for the calculations. 
• Shutter speed is what is required for each exposure. It is the same as I indicate in the instructions below. 
• Aperture is a variable based on what is need to get a Zone V exposure at 1/30 of a second for the film speed used. 
• Total Exp is the total exposure time the film has received for each exposure. Note for Zone V the total exposure is .033 or 1/30th of a second. 

Instructions

The process is as follows then.
1) Insert the film holder in the camera focused on the white target  background that has been metered for zone V.
2) Set the shutter speed for 1/500 and the aperture for one stop greater (f16 in this example) than the metered value for 1/30 for Zone V.
3) Pull the dark slide out to the position that leaves it covering just 10mm of film (Figure 3 above).
4) Make the first exposure. This will be zone X 5 stops less exposure than Zone 5. The entire sheet of film except the portion hidden by the dark slide now has the equivalent of 1/1000 sec exposure at the Zone V aperture (f11 in the example).
5) Next slide the darkslide in 10mm and make the next exposure. This exposure is the same 1/500 second at one stop greater (f16 again) than the zone V exposure. This leaves the rest of the film with 1/500 at the Zone V aperture (f11) total exposure (2x1/500 @ f16).
6) Again slide the darkslide in 10mm and make the next exposure by changing the aperture to the one used for the Zone V exposure (f11 in  our example). The shutter speed is still 1/500 of a seconds. This will leave 1/250 exposure for the exposed film. The rest of the exposures proceed with the same aperture while the shutter speeds decrease for each exposure now.
7) Move the darkslide 10mm. Expose with the shutter one stop slower.
8) Repeat step 7 until the last exposure at 1/2 second.

Note 1: The total exposure for the darkest Zone 0 strip is 1 second so reciprocity should not be a factor. (Lower right cell in the table above.)
Note 2: The aperture you use is purely determined by the film's speed, target shutter speed of 1/30 and the scene brightness. You can shoot wide open if needed as we are not aiming to make a clear or focused image.

My Setup

I used a utility light to light a wall in a room where I don't have to worry about sunlight. I set it up as below in the photo. I taped markers to the wall and moved them until they defined the edges of the image on the ground glass. (I removed them after that.). I could then use the markers to check my metering. My spot meter confirmed a variation of less than a 1/3 of EV across the area of the wall.

Blank wall setup. Camera in foreground. 

Development

As I said I am using a single shot HC-110 for up to 4 sheets of 4x5 or one sheet of 8x10. As discussed in my previous post I settled on Dilution B which for a Cibachrome drum development means I need 7.5ml of HC110 with 232 ml of water (1+31). Single-shot development should give more consistency in development as the freshness of the chemicals is not in question. I no longer have to record how much film has been in the developer nor remember how old the developer is. HC-110 also has the benefit that the concentrate has a shelf life of years especially if kept with no air in the bottle.

This I find easiest to do using a gram scale. I carefully measure out 7.5ml of HC-110 and weigh it. I get about 9.3 grams. Then each time I need to mix my developer I can place my mixing bottle on the scale, zero out the reading with the tare function. Then add HC-110 carefully until I get the correct weight (9.3 grams). I then zero the scale again and add water to 232 grams (1 millilitre of water weighs 1 gram). This method saves me using a separate measurement vessel to measure the HC-110 as HC-110 is a syrup that then needs to be repeatedly rinsed from the measurement vessel.

Massive Dev Chart gives a nominal development of FP4+ at box speed (125) at 20C 9:00 minutes which I will use as a starting point by scaling to ASA 100 which results in 8:00 minutes (480 seconds). I then compute -20%  (384 seconds) 6:24 minutes and  +20% (576 seconds) 9:36 minutes. My drum development means constant agitation and as such will develop the film more that the standard routine for tank development of agitate for first minute then ten seconds for each minute afterwards. This will probably mean a lower final development time from the Massive Dev Chart as well.

First Pass Results

Well I did as I planned however when I cut the film into strips to develop separately I accidentally cut them on the short axis and so the cuts followed along the lines of the zone not across. Hard to understand how this happened but it is done in the dark so things are more prone to mistakes.

First Test Strip (with cuts in wrong direction).

I discovered this after I developed the first strip at the nominal time and while I was developing the -20% strip. Consequently I developed all the strips at the same development time. I reused the developer for each strip however as they were only 1/3 of a sheet of 4x5 film and there is ample developer for an 8x10 sheet.

Scanner as Densitometer

My plan is to use my scanner as a densitometer. I found this article that discusses the subject. The author suggests another imaging SW package called  ImageJ which can be used to extract 16-bit values from a histogram if your software cannot not do this (Photoshop Elements for instance). I composed a short video to describe the process of converting scans to densitometer readings.


Zone System Film Test and Development from Doug Morse on Vimeo.

The results I scanned in linear 16-bit mode. My version of Photoshop Elements only gives 8-bit values for histograms so I used ImageJ and built a table of values and calculated density with the formula given in the article. Value is the number I got from the ImageJ histogram for the selected pixels in each zone of the negative. Ideally Zone I should be about .1 and Zone V should be .7 Zones XI and X are very close together in this test, ideally they should be spread out more. Each .3 of density is 1 stop or doubling of exposure  (log10(2) = .3). (The densities are computed by reference to the film base Value of 65447.)

Zone
Value
D=Log10(filmbase/Value)
10    
253      
2.41
9
310
2.32
8
548
2.08
7
949
1.84
6
1796
1.56
5
3201
1.31
4
6517
1.00
3
13916
0.67
2
26008
0.40
1
40235
0.21
0
58860
0.05
Base
65447

My results are too dense in each case indicating I need to reduce development time. The next experiment will be to re-expose a piece of film and try -20% development making the new time 6:24 at 20C.



Second Pass Results

I made another test strip exposure exactly as outlined above and ran the -20% development. This got much improved results. Here is the test strip... 





The scanner results are below in the orange column while the blue column are the previous results fro comparison. .

Density Calculations for first 2 tests. 



Now Zone V is closer to the target of 0.7. Zone VIII target of 1.3 is much closer. The upper zone densities are much lower which should help with getting more detail in highlights(remember the dark areas are highlights in a final print). The separation in this area is much better as well.  The two plots are compared below with density on the y-axis and zone on the x-axis. The newest test is in orange and the original is in gray. 







Zone 1 should target 0.1 so this indicates I  need to use a lower ISO. This will raise this density and presumably the others. 




Third Pass Results

Next I exposed at ASA 80 to bring up the zone 1 values closer to 0.1. The scan and summary are below. These values are a little higher than the Zone 1 target of 0.1. Technically ASA/ISO is between 100 and 80 ideally in this case. Zone V is right on at 0.7 and Zone VIII is close to 1.3. 
Third Pass Scan

Summary of Scan Densities


Plot of Scan Densities



I would conclude that  I need to increase ISO slightly but I will probably stop here at ASA 80. 

Actual Experience

I went out later and shot and developed using these new parameters. Below are example images metered for ASA 80 and developed in HC-110 at -20% development time.

I think the range of detail is very good. Below is a crop of the second photo showing shadow detail in the tree trunk area.