Film testing procedure - questions on exposure

Sorry if this the 307th time this is asked here, but I found no really good other thread to start with.

I'm planning to do a film test according to the method described in Way Beyond Monochrome 2nd edition.

• I'm going to tape my Stouffer 21 (T2115) step wedge/tablet to a small diffusion material (a piece or two of paper in a plastic cover)
• I'll tape the step wedge & diffusor to a north facing window and will try to avoid any hotspots/similar, I will try to keep the exposure over the paper at 1/10 th of a stop or below (if possible)
• I'll mask of the area around the step wedge using foam boards. I'll try to include some marker indicating which sheet is which for future reference
  
• I'll shoot each sheet at box speed
• I'll develop the films at 4, 5.5, 8, 11 & 16 minutes (Rodinal 1+49) 6 at a time and will use undeveloped but exposed sheets (from normal photography) where possible and a mix of sheets exposed to daylight and unexposed where I don't have any pictorial film to develop with
• I'll measure densities with my darkroom meter (RH Design) and use the Excel sheets found here by the author of WBM

I think above will (hopefully) be enough precision for all my needs. Please chime in if you have any worries or if I have misunderstood anything.

The only question which I'm not sure of are related to exposure:

• Where do I meter? I tried a dry run but discovered that my spotmeter (Minolta Spotmeter F) could only detect small differences between all steps, the different between transparent and opaque was around 1 stop?
• Some people write that I should focus on infinity but what I've read is that I should use a slide duplicator if possible. As I'm shooting 4x5" I guess I can just expand my bellows until I run out and account for the bellows extension factor. What would you recommend?

I'm aiming to try to calibrate 3 films, as that is what I have at home and since I already will be wasting a lot of sheets I will try to optimize it a bit. They all have similar development times so I hope I will gain some information at least.

I'd just photograph a uniform target and set it at zone 1 at various ISO readings. Process the film and see which sheet drops your exposure by 1/3 stop when placed over any hand-held meter.

To get a film curve, I'd contact print the step wedge on to the film directly in the darkroom. You won't have sensitivity data, only the shape of the curve, but that is OK because you got your sensitivity data (ISO) from the in-camera test above.

Oscar you didn't mention what camera/lenses or films you will be using. For example, each large format lens is probably mounted in a different shutter as well as say Hasselblad lenses with their own shutters plus the shutter curtain. Also different photographic papers have different looks. A rather simple test to determine a personal ISO similar to that mentioned by ic-racer or this : with a lens cap over the lens click off a couple of frames*, with a target (a gray card is the easiest) filling the entire frame not necessary to be in focus in a constant light source at box speed expose at +1/2 or 1/3 stops up to the metered exposure then down by -1/2 or 1/3 stops, develop as per mfg's time/temp. Then take the clear unexposed frame and make a test print at f8 for different exposure times ie moving the cover every 5 seconds, when dry see where there is a difference from pure black. Cut enough pieces of the paper you print on to match the number of "stops" exposures you made, expose each frame on a separate piece marked on back according to the 1/2 or 1/3 stops at the time it took to change from pure black @f8. Develop and when dry the one that most closely matches your target will indicate what adjustment if any to the ISO you should make. *The clear frame is to take your film fog into account. You would have to do this for each film. Probably more trouble than it is worth. That said I have no problem getting properly exposed negatives with the Ilford films at box speed and their development recommendations.

http://www.jeffreyglasser.com/

About the meter indication from the step wedge. I did a test similar to this and tried to use a spot meter to analyze the brightness of the steps for exposure calculation. I also found strange meter readings. I concluded that the spot meter cannot focus the small area of the step it is too close to the meter and blurred and so is inaccurate. When I attached an enlarging lens (maybe 50mm FL?) to the front of the spot meter lens the system was able to focus on the small area of the step tablet and I found logical brightness numbers.

I'm planning to use my 210 mm lens on my 4x5" camera, to keep things consistent. I hope to keep the shutter speed to 1/15 th of a second or so, as long as I don't fall below 0.5 s it shouldn't matter much.

For this step I'm mostly interested in testing my development time, film speed test is easy to fix later once the development time is established.

My kitchen darkroom is not dark enough for doing contact printing, sadly. That is why I'm trying to tape the step wedge on my window.

Oscar Carlsson said:

...For this step I'm mostly interested in testing my development time, film speed test is easy to fix later once the development time is established.-

Click to expand...

In my experience, film speed and development are interrelated; (extreme example - Rollei IR 400 as a non-IR film): Box speed is 400. All of my testing says (with Rodinal and HC110), this is about an 80 ISO film without IR filters. I've done significant tests twice now because I thought it couldn't be that far off. So if I suss out my dev time for 400, and then find my ISO is 200 or 100 or 50... I'll have to re-think my dev time, by a significant margin. Those highlights I'm judging will be way off.

I eventually got tired of testing that didn't suit the images I would be making (primarily studio with stobes and people). Now to test, I set up a still life I can leave up for a few days. I include a styrofoam packing block (if that holds detail - if I can still tell it's not a blank white card in the final print tests - my highlights are correct). There's a gray scale chart in there, a dark plaid flannel shirt (various levels of shadow detail), a gray card, etc. I spot meter the gray card, and compare it to an incident reading - they should be about the same. I check the styrofoam for 3 stops over, and a reasonable shadow area where I want clear detail for 2 stops under, and a coarse black fabric for 2 stops under (textural detail). I'll even step into the set and shoot to see skin tones. I also shoot a frame or sheet of a blank card and shoot it 4 stops under.

I don't judge the negs on the light table, I judge how they print at 2.5 - 3.5. I do a strip test with the 4-stops-under card shot and find the time to hit just-shy of max black to full black. That gives me the time for film base +fog, the max black my paper can reproduce with this film in this developer. I don't move the enlarger, and do some small prints of the still life at the max black time (we don't want to sacrifice max blacks to get decent mids and highs, right?) Blow dry off the prints, and instantly I know where I'm at. Shadows good? Do I have a hint of texture in the +3 area? I'm good, and if not I can take a pretty good guess at a new dev. time or if another ISO is going to work better for me.

This has taught me a lot - primarily it's taught me to consider developer dilution along with time. I really like Rodinal at 1:25; the highlights are great, but there's some compression in the low mids (due to less compensation that 1+50). So in a controlled situation, I can light and expose for a little more shadow detail (usually just upping some fill light). I usually develop around 1+30 now.

I tend to do my first tests with 35mm roll film - I shoot, say, a four stop bracket and advance the film 1 frame, set the shutter to bulb, remove lens, and stick a square of scotch tape right on the film. Advance the frame and shoot another bracket. In the darkroom, I can feel the tape, cut the roll in those spots, reel up one bracket and store the rest. So to get a grasp of one particular film, with multiple ISOs, different dev times based on what I'm seeing at a given ISO, and different dilutions for low-mids, I can use one roll of film, maybe 4 sheets of 8x10 paper, and an ounce of dev concentrate (I re-use the developer since it's 'expecting' 36 frames but only acted on 3 to 5 - I just pour it in an airtight bottle and get it back to temp) in one afternoon.

YMMV of course, but this has really amped up my understanding of specific films and developing, and done it very quickly.

Oscar Carlsson said:

I'm planning to use my 210 mm lens on my 4x5" camera, to keep things consistent. I hope to keep the shutter speed to 1/15 th of a second or so, as long as I don't fall below 0.5 s it shouldn't matter much.

For this step I'm mostly interested in testing my development time, film speed test is easy to fix later once the development time is established.

My kitchen darkroom is not dark enough for doing contact printing, sadly. That is why I'm trying to tape the step wedge on my window.

Click to expand...

Your step wedge needs to be contact printed against the film. If you photograph the step wedge you would need to put your meter cell on the film plane in place of each projected step to see what the value the film would see. That is just crazy.
When you contact print the step wedge (either in the darkroom or taped to your film in the film holder of the camera) you can use the actual density of each step to calculate your curve.

Take a meter reading of the glass without a step wedge. You want that to be "white" (dense on the negative)... so why not just place the light table on Zone IX.

After you take the meter reading put the step wedge in place...

If you are shooting in camera where the step wedge is on the glass, the scale needs to be in focus. That may mean you have to compensate for bellows extension. After compensating for bellows extension, also open up about 4 stops from meter reading (to place meter reading on Zone IX)

If you are shooting in camera but taping the step wedge to the film, then throw the camera out of focus by focusing at infinity. You won't need bellows compensation in that case. Still place exposure on Zone IX... You could open up another stop or two if you feel like it.

Bill Burk said:

Take a meter reading of the glass without a step wedge. You want that to be "white" (dense on the negative)... so why not just place the light table on Zone IX.

After you take the meter reading put the step wedge in place...

If you are shooting in camera where the step wedge is on the glass, the scale needs to be in focus. That may mean you have to compensate for bellows extension. After compensating for bellows extension, also open up about 4 stops from meter reading (to place meter reading on Zone IX)

If you are shooting in camera but taping the step wedge to the film, then throw the camera out of focus by focusing at infinity. You won't need bellows compensation in that case. Still place exposure on Zone IX... You could open up another stop or two if you feel like it.

Click to expand...

Thank you, that was what I think I needed to know. I went ahead and made the exposures today, taped the step wedge to a window (high) and used the camera from slightly below, so I had the overcast sky as pure background. Just developed the first set of negatives, will try to develop next set later today.

Oscar Carlsson said:

Sorry if this the 307th time this is asked here, but I found no really good other thread to start with.

I'm planning to do a film test according to the method described in Way Beyond Monochrome 2nd edition.

• I'm going to tape my Stouffer 21 (T2115) step wedge/tablet to a small diffusion material (a piece or two of paper in a plastic cover)
• I'll tape the step wedge & diffusor to a north facing window and will try to avoid any hotspots/similar, I will try to keep the exposure over the paper at 1/10 th of a stop or below (if possible)
• I'll mask of the area around the step wedge using foam boards. I'll try to include some marker indicating which sheet is which for future reference
  
• I'll shoot each sheet at box speed
• I'll develop the films at 4, 5.5, 8, 11 & 16 minutes (Rodinal 1+49) 6 at a time and will use undeveloped but exposed sheets (from normal photography) where possible and a mix of sheets exposed to daylight and unexposed where I don't have any pictorial film to develop with
• I'll measure densities with my darkroom meter (RH Design) and use the Excel sheets found here by the author of WBM

I think above will (hopefully) be enough precision for all my needs. Please chime in if you have any worries or if I have misunderstood anything.

The only question which I'm not sure of are related to exposure:

• Where do I meter? I tried a dry run but discovered that my spotmeter (Minolta Spotmeter F) could only detect small differences between all steps, the different between transparent and opaque was around 1 stop?
• Some people write that I should focus on infinity but what I've read is that I should use a slide duplicator if possible. As I'm shooting 4x5" I guess I can just expand my bellows until I run out and account for the bellows extension factor. What would you recommend?

I'm aiming to try to calibrate 3 films, as that is what I have at home and since I already will be wasting a lot of sheets I will try to optimize it a bit. They all have similar development times so I hope I will gain some information at least.

Click to expand...

sounds to me as if you are on the right track. On the Stouffer, I usually spot meter on the wedges #15 or 16 or if possible average meter for the whole sheet;some experimentation may be necessary but it's not too critical because,the density measurements are relative and not absolute; you are later plotting density over exposure differences and an exposure error can be rectified by a simple horizontal shift of the curve.

Oscar Carlsson said:

I'm planning to use my 210 mm lens on my 4x5" camera, to keep things consistent. I hope to keep the shutter speed to 1/15 th of a second or so, as long as I don't fall below 0.5 s it shouldn't matter much.

For this step I'm mostly interested in testing my development time, film speed test is easy to fix later once the development time is established.

My kitchen darkroom is not dark enough for doing contact printing, sadly. That is why I'm trying to tape the step wedge on my window.

Click to expand...

Backwards - Establish the film speed first. This has been the established order of things since at least the 1930's.

ic-racer said:

I'd just photograph a uniform target and set it at zone 1 at various ISO readings. Process the film and see which sheet drops your exposure by 1/3 stop when placed over any hand-held meter.

To get a film curve, I'd contact print the step wedge on to the film directly in the darkroom. You won't have sensitivity data, only the shape of the curve, but that is OK because you got your sensitivity data (ISO) from the in-camera test above.

Click to expand...

the OP is trying to follow a more sophisticated procedure to gather the max amount of data from the min amount of testing and that works well with his setup.

ic-racer said:

Your step wedge needs to be contact printed against the film. If you photograph the step wedge you would need to put your meter cell on the film plane in place of each projected step to see what the value the film would see. That is just crazy.
When you contact print the step wedge (either in the darkroom or taped to your film in the film holder of the camera) you can use the actual density of each step to calculate your curve.

Click to expand...

+1 to that. With all the talk about multi coated lenses and low flare: there is still plenty of flare left to completely obliterate the results from a film test shot through a lens. Even if you plan on shooting with this lens for the rest of your life, scenes with different amount of contrast will give different amount of flare and therefore different results, so you have to test the lens by itself. The whole step wedge test is based on the assumption that the area surrounding a spot has no impact on its exposure and development. This assumption will hold for development as long as the step areas aren't tiny, but it will quickly fall apart when lens flare comes into play.

RalphLambrecht said:

the OP is trying to follow a more sophisticated procedure to gather the max amount of data from the min amount of testing and that works well with his setup.

Click to expand...

I'm planning to do a film test according to the method described in Way Beyond Monochrome 2nd edition.

Click to expand...

Ok I missed that he is doing the method from your book. Could you post the page from the book he is following? Otherwise, the responses here might be leading the OP off track.

Ok, he wants you to use the camera shutter to control the step wedge exposure. Mask it well and use a coated lens, any stray light will alter the transmission data from the target when it gets to the film (fog).

I didn't mask it so I guess that my first try will not be perfect

Even though it wont be perfect and the results not 100%, I will at least have some better information than the current guesswork (the amount of crappy development times & information on FP4+ is...annoying).

Thanks for all your responses!

Hi there,

I understand that you wish to follow the testing in Way Beyond Monochrome 2nd edition. As with all of the various Zone System testing regimes, they all read very complicated and many require a sensitometer but, as I know from experience, trying to write a simple straightforward explanation of a simple test is a challenge and writing all the steps down makes it look really complicated.

May I suggest another approach? The system I teach can be found here:

(there was a url link here which no longer exists)

Please refer to my post no #3

Once you have done the tests (note that I do not recommend constant tests of materials but rather doing it once and then sticking to the equipment, film, development technique and methodology) all the beginner has to remember is either:

• To go in close and meter the darkest shadow area where they wish to retain detail and adjust the meter’s recommendation by closing the aperture down by two stops, increasing the shutter speed by two stops or a combination of the two.

or

• To go in close and meter the brightest highlight area where they wish to retain detail (excluding the sky and on a dull day this may in fact be a light grey wall or even wet brickwork reflecting the sky) and adjust the meter’s recommendation by opening up the aperture by three stops, reducing the shutter speed by three stops or a combination of the two.

Whether you meter the important shadows or important highlights is not important and generally simply a question of which is easiest to reach.

That is it, no need for years of wasting film and time trying to build experience of how to compensate for different lighting conditions. It also short circuits many of the suggestions given as to why people are ‘wrong’ to test for a personal EI, such as:

“they meter too much sky and have not learned to take a light reading correctly”
If you follow any version of the testing strategy, you will never meter the sky and will require 0 years experience of how to meter correctly because you either meter the important shadow area or the important highlight area. Absolutely no need to spend years building up knowledge and experience.

“the meter is out of calibration and needs adjustment”
It is really not necessary for a meter to be calibrated correctly. What is of fundamental importance is that it is CONSISTENT. Any inaccuracy will be compensated for by the real world testing method as described.

“the camera/lens is out of calibration and needs a CLA”
It is really not necessary for a camera/lens to be calibrated correctly. What is of fundamental importance is that it is CONSISTENT. Any inaccuracy will be compensated for by the real world testing method and how many people earn enough to pay for a CLA on a good quality camera?

If you undertake practical tests using your equipment none of the above matters because it will all be automatically compensated for during the tests. Even if your camera is working as per blueprint (highly unlikely given required production tolerances) it cannot be assumed that the box speed will suit your equipment, exposure and development technique.

Bests,

David.
www.dsallen.de

David Allen said:

“the camera/lens is out of calibration and needs a CLA”
It is really not necessary for a camera/lens to be calibrated correctly. What is of fundamental importance is that it is CONSISTENT. Any inaccuracy will be compensated for by the real world testing method and how many people earn enough to pay for a CLA on a good quality camera?

Click to expand...

Hi David Allen,

I always enjoy your alternative offerings, as the practical test method can work well and everyone really needs/wants to follow their own path.

But... This made me chuckle...

Cameras today may "need" a Clean Lube and Adjust today, even if it's just to replace aging light seals.

What made me laugh is that nobody makes enough money to get ALL their cameras serviced...

But... most probably have considered buying one more camera... and that money could be better spent just getting one good camera serviced, so that you will have a camera you can rely upon.

Otherwise... you might find yourself telling stories like this... When offering my scouts a camera to shoot for the photography merit badge, I discovered the folly of my ways... while I have many cameras to offer... many are in a condition which requires adaptive shooting behavior. For example I might have to say about one camera... "don't shoot at speeds over 1/250 because the shutter is capping" or "the flash contacts don't work" or "if the mirror doesn't come down, don't worry just shoot a second shot aimed the same because the shutter is fine and next time the mirror will come down"

Oscar Carlsson said:

I'm planning to do a film test according to the method described in Way Beyond Monochrome 2nd edition.

Click to expand...

Cool! It's great fun!

I recently did this, to figure out how to develop the new FOMA RetroPan 320 film to work well with my particular print making process involving my Durst L1200 condenser enlarger and RH Designs Analyser Pro enlarging light meter/timer. The result was amazing: the first thing I did after working everything out (using Ralph's spreadsheet), was to go out and shoot a bunch of 4x5" negatives, under varying light conditions, and then develop them according to the test results. Finally, I printed all those negatives on grade 2, letting the Analyser Pro choose the exposure according to my original visualization - and it was spot on, every time.

Ralph's method helps you get the optimal negative for your printing process.

However: if, like me, you're using a condenser enlarger, you may want to tweak Ralph's spread sheet a bit. He assumes a diffuser enlarger, but I've modified the spread sheet to more completely obey your desired negative contrast range - which is why I was able to get it right for my L1200.

ic-racer said:

Ok, he wants you to use the camera shutter to control the step wedge exposure. Mask it well and use a coated lens, any stray light will alter the transmission data from the target when it gets to the film (fog).

Click to expand...

Flare is going to cause the resulting graphs to have a very long gentle toe... Note that it's not the characteristic of your film to have this very long gentle toe.

@RalphLambrecht,

I think the camera shooting test causes a problem of flare in the toe region. I've seen flat toes when I drew graphs from test data that some people have posted (and when they described that their tests were done using a transparent step wedge on glass shot in a camera).

I think this could be alleviated by shooting an additional set of five sheets of film with 1/10th (or maybe 1/100th) the exposure of the first set and developing them in pairs...

Perhaps the use of a 1.0 or 2.0 Neutral Density filter would make cutting the light for the second set of exposures more convenient and it would be reasonably precise.

The data from a pair of such shots could be graphed independently, and where the two graphs depart in the toe you could see how much the flare affects the results.

As I said, I've seen the influence of flare in other's test data, so I believe there is a problem.

I got this idea of doing multiple exposures by seeing the way the Sekonic gray scale test target works. Sekonic has a gray card where there is a set of seven grays, one-sixth of a stop apart (so the set covers "one" f/stop of range) in the middle gray region. The test instructions are for you to shoot many exposures of this target in one-stop differences. Thus using a camera test, you can cover a very wide range of exposure tests.

But of course, it's a lot of data reading to follow Sekonic's entire series. It isn't necessary to have data in sixth-stop "resolution" so the normal half-stop step wedge can be used. And I don't know exactly where flare becomes a problem but I believe it is somewhere where the light ratio is between 1:100 and 1:1000

ic-racer said:

Ok I missed that he is doing the method from your book. Could you post the page from the book he is following? Otherwise, the responses here might be leading the OP off track.

Click to expand...

sorry but ,I don't have a pdf of that page alone