Home made film testing

[Mats_A]

I know this is a topic that has been discussed to death here and on the Intertubes but allow me one more flog of this near dead corpse.

Okay. Personal film speed and personal development times. I have read about various methods for arriving at this. I have even tried several of them with more or less success. I have an Analyser Pro that has a (sort of) densitometer function. I thought of using this for my testing.

The problem I found with many methods described is that they ask for you to adjust the exposure in 1/3:rd of a stop. My Nikon FA does not allow for this in manual mode. In P or A mode it will use whatever f-stop is appropriate but will of course only show whole stops/times on the screen. So how do I test for Zone I on this camera? I normally use it for snapshots and let the camera take care of the metering. So what I really want is to find out what ISO to feed the camera and how long to develop.

I came up with following solution and would like some input regarding this. Mostly I am interested in finding out if I have everything thought out the wrong way (I mean 180 degree wrong way)

1. Film in camera (let's say T-Max 100)
2. Camera on tripod and pointed at a uniform object (mat board or such) that fills the whole picture.
3. Take one shot in manual mode and lens cap on for reference.
4. Put camera in P-mode. Program mode, camera meters everything. This is how I most often use this camera. Alternative is Aperture Priority.
5. Adjust ISO to 1600. This should underexpose by 4 stops and be Zone I.
6. Take a shot.
7. Adjust ISO down 1/3 stop and take a shot.
8. Repeat down to ISO 800 and then bracket 3 shots 1/3 stop above 1600

- Waste the rest of the shots or remove film in darkroom condition.
- Develop per normal.
- After washing and drying the film use the Analyser densitometer to measure the first frame as base+fog = Log 0.0
- Find the frame that measures nearest to Log 0.1. This should be Zone I and also my personal film speed for this camera and this film.

Personal development time.
1. Load rest of film in same camera or use new film.
2. Use my spanking new personal ISO on my camera.
3. Use same setup with mat board as previously.
4. Overexpose 4 step by adjusting ISO down from my personal film speed. If I run out of ISO:s use 2 step exposure compensation and 2 step ISO. So if my personal ISO for TMAX is 80, compensate +2 stops and use ISO 20.
5. Shot the whole film at this setup.
6. Remove film in darkroom and cut in 4 pieces. Store safely.

- Develop first piece as you normally do for this film/developer combo. Let's say 8min.
- After washing mark film strip as Normal (8 minutes)
- Develop the rest 10%, 20% and 30 % less time and mark them.
- The strip that reads Log 2.5 should be Zone 9 and my personal dev time.

I even think this could be used for finding N-1 and N-2 dev times. Not that I use much of those with roll film.

If you have managed to stay awake for this long could you kindly inform me if this is even semi-correct or a complete brain fart. Would like to know before I waste a roll or two on this.

Many thanks

Mats

 

[markbarendt]

For myself I have come to believe that testing like this is well, over rated.

I say this because Films like T-Max 100 normally have a lot longer straight line than can be printed in a "straight print". There is little worry of actually reaching the film's shoulder because the paper's printable curve is quite short in comparison.

What is important is finding out what EI gives you a reliable placement of your subjects and separation of the tones on paper and which curves, -, +, or N, work best with which lighting situations.

The goal of testing is not necessarily to find the film's absolute limit, but to make getting the print/the look you want, easier.

 

[Steve Smith]

For myself I have come to believe that testing like this is well, over rated.

Me too. This is my lazy person's version: http://www.freewebs.com/stevesmithphoto/personal.html


Steve.

 

[Usagi]

Testing may be overrated, but it is also useful tool when not going too deeply in it.

Trying to get own exposure index within 1/3 stop or calibrating developing times with fraction of stop (like N + 0.7) is ridiculous as such accurate results would require way more accurate processing, metering etc. Paying attention to error factors of each measurements...

With most cameras, you even can't set exposure that precisely. Only by steps of 1/2 or 1 stops.

When speaking of zone system, the goal of calibration is to get negative that can be turned 'easily' to print that photographer had visualized before exposuring the negative.
It can have a quite big marginals.
Actually, you can use zone system without doing much contrast alternations during film developing if you know that you can get the print that you had in your head before exposing negative by some other manners, like varying paper contrast etc.
You can get really good results just by calibrating everything roughtly and looking the results from the prints.


Don't get me wrong. The testing gives always valuable information. Sometimes people just forgot the basic principles and goes too far.

The one good example is zone system; how many uses it mainly for fitting the whole brightness range of subject to the negative's 'normal' printable range? Instead of figuring where they wan't to place each brightness value of the subject at the final print and trying to use combination of exposure and contrast (N- or N+) for help to achieve that?
There's many photographers who measures the whole brightness range - even using the tenths of stops, then exposing so that everything is captured and then developing withing accuracy of second. All that based of overly precice interpretation of testing results. While the materials would allow much wider error marginal to work with.

 

[Steve Smith]

how many uses it mainly for fitting the whole brightness range of subject to the negative's 'normal' printable range? Instead of figuring where they wan't to place each brightness value of the subject at the final print and trying to use combination of exposure and contrast (N- or N+) for help to achieve that?

I have a simplified version of that too: http://www.freewebs.com/stevesmithphoto/contrast.html


Steve.

 

[Diapositivo]

The problem I found with many methods described is that they ask for you to adjust the exposure in 1/3:rd of a stop. My Nikon FA does not allow for this in manual mode.

Mats

Mats, I think your tests would be carried out more easily and more reliably if you use manual exposure.

For most lenses*, the tick "stops" on the aperture ring are just a way to make aperture selection more comfortable, e.g. to allow you to vary aperture without looking at the aperture ring.

In general, if you set your aperture at 1/3 between say f/8 and f/11, the final exposure will actually be done at 1/3.

Using the manual mode of your Nikon FA with normal AI lenses you can use 1/3 of EV apertures.

I sometimes use 1/3 position on my lenses, even though they "tick" every 1/2 EV, and did not break any lens so far.

Fabrizio


* DISCLAIMER: use your lens at your own risk. I cannot totally exclude that some lenses can be damaged if used with the diaphragm in intermediate positions.

 

[Mats_A]

Diapositivio.
This is exactly what I am trying to circumvent with this setup. Adjust the ISO in 1/3 stops and let the camera take care of the aperture.

r

mats

 

[Mats_A]

Me too. This is my lazy person's version: http://www.freewebs.com/stevesmithphoto/personal.html


Steve.

Yes I know about this. Use half the manufacturers speed and develop for 25% less. I have been using that. But my inner engineer keeps nagging at me that I need to know exactly what ISO and time to use. Silly me. Guess I just like to test and draw tables and curves

r

Mats

 

[Usagi]

Silly me. Guess I just like to test and draw tables and curves

That's my problem too, but I don't tell it anybody

The all curves and charts I have drawn are useful, especially when I interpret them a bit lousy.

I can't stop thinking photography via zone system as I have used it so many years and learned to think subject as final print, mapping subjects tones to print tones in my mind.
But I can do that with a lot of less testing that I used to do.

 

[Steve Smith]

But my inner engineer keeps nagging at me that I need to know exactly what ISO and time to use.

I tend to ignore my inner engineer. At work (electronic and mechanical design engineer) I am much more of a 'do it and see what happens' sort of person rather than a 'plan it out in intricate detail first' sort of person.

At college, I was the person who would write a program, get it working, then worry about drawing up the pointless flowchart later.


Steve.

 

[MattKing]

Mats:

Your test regimen looks quite usable.

I would suggest, however, that you add something like a test wedge or a full range scene to one side of your mat board. That way you would have a visual check of your analyzer's results.

 

[Diapositivo]

Mats, it is my understanding that you are using various ISO settings because your FA does not allow you to set apertures at 1/3 EV.
It is also my understanding that your FA actually does allow you to set apertures at 1/3 EV although probably I did not express myself clearly.
So IMO you can keep ISO constant, shutter speed constant, and vary aperture by 1/3 EV intervals, and your test will be easier to perform.

 

[Allen Friday]

The basis test seems sound. If I follow what you are doing, you are basically tricking your camera to automatically adjust the f/stop in 1/3 intervals. You can not do it manually, so you are adjusting the ISO setting on the camera by 1/3 stops to force the camera to compensate by changing the aperture 1/3 stop. Sounds like it should work. For a 1/3 stop adjustment in ISO, the camera will have to automatically adjust either the shutter speed or aperture to get the same exposure. This assumes the lighting on the subject does not change at all.

You might check your results by doing a quick "minimum time for max black test." Contact print your frames for the minimum time to make the blank frame match the black of the paper where there is no film. Look at the other frames and find the one just a bit lighter than the black. Figure out the ISO used for this frame. It should match the ISO determined by your densitometer tests. It's a quick check--worth one or two pieces of paper. (You can do the same thing in reverse to test for highlights with the second roll).

 

[Maris]

So how do I test for Zone I on this camera? I normally use it for snapshots and let the camera take care of the metering. So what I really want is to find out what ISO to feed the camera and how long to develop.

Using through-the-lens metering will undo the value of your film testing. Given real world subject matter containing a variable mix of dark bits and light bits it is highly improbable that the camera's meter will set the correct exposure.

Zone 1 negative density corresponds to Subject Luminance 1 which renders as Print Density 1. This is a very dark tone without detail but not quite absolute black. Through-the-lens meters don't "know" to read this dark part of the subject and ignore the rest. A spotmeter, on the other hand, can isolate parts of the subject matter and permit calculation of exposures that place specific subject luminances on specific exposure zones.

In practice photographic materials have some exposure latitude and through-the-lens metering delivers a high proportion of usable exposures whether the film is exhaustively tested or not.

 

[Allen Friday]

How anal retentive is your inner engineer?

Is that a silly question to ask of an engineer?

If you are a ten out of ten on the testing scale, you need to expose the rest of the roll to normal scenes--half at box speed and half at 1/2 the box speed. If you develop a roll of film with only 8 exposures, and those are at minimal exposure, then your developer will not be used up as much as it would be with 24 or 36 exposures made of normal scenes.

That could be turning up the AR scale to 11.

 

[markbarendt]

Yes I know about this. Use half the manufacturers speed and develop for 25% less. I have been using that. But my inner engineer keeps nagging at me that I need to know exactly what ISO and time to use. Silly me. Guess I just like to test and draw tables and curves

r

Mats

I get it now this isn't about photography.

One of the other reasons that I gave up on testing was that the speeds I came up with were, wait for it, virtually equal to box speed.

What turned out to be much more interesting/fun is creative exposure placement.

 

[Mats_A]

Thanks all for answering my Anal Retentive Inner Engineer (ARIE). After rereading the testing chapter in "Way beyond monochrome" and even asking Chris Woodward some questions by email I have come to understand that the first part of my test is doable. Ie I can get a usable film speed with it. The other part is complete b***ht. Wont work like that.

Maris: You are mst certainly right about this. Didn't think about that.
Allen: He can be VERY Anal Retentive. And this issue comes up also in the chapter on testing in WBM. (not about him being AR but using whole films)

I think I will put my ARIE to sleep for a while now. I will concentrate on using Ilford FP4+ for my roll films at 2/3 below box speed. I will develop them in HC110 dilution B for 85% of Ilfords time. That would be about 7,5 minutes.

If I stick to this regime for a while I hope to learn enough to maybe understand what I need to change.
But I am pretty sure that my ARIE will pop up his ugly head again after about 10 rolls.

Hmmm... Maybe the highlights are blocked? How do you KNOW they are not blocked? Basically you are just guess...

*SMACK* Shut Up!

r

Mats