I got a step wedge... now what?

[darinwc]

I got a step wedge. Its .5 inch wide and 5 inches long with 21 steps labeled from 1 to 21.

Questions:
1. do the numbers correspond to to the density number I hear people talking about? Like number 5 correlates to a density of 5?

2. how do I test my film? It would be pretty easy to tape it on a 4x5 sheet of film in a holder but I have no idea how I would go about testing 120 or 135 film.

3. I dont have a densitometer. What if I use the step wedge to calibrate my scanner and then use the scanner to plot the film curve? (ive never done any plotting of film curves on my pc so i dont even know if i have software to do this)

 

[Nick Zentena]

No the numbers are more like ND filters. Every 3 is one stop. IIRC.

 

[Ian Grant]

Simple answer is throw it away, you really don't need one.

However there is an obsession for them in the States. You must realise its far more important to master your Step Wedge, than make images

Then get real, Ansel Adans - The Negative is excellent, I'm sure there's a few more US publications. But . . . . ; . . all the photographers who go down the anal retentive route have lost their vway and are history

Ian

 

[Ole]

The 21-step wedge I have is half stops. 0 is film base+fog, 2 is one stop darker, and so on.

Densities go in logarithmic steps, so that 0.3 is one stop. That makes the darkest step on your wedge 10 stops, or D 3.0.

 

[darinwc]

Well ian I looked through my prints and negatives today an i was really amazed at how inconsistant they were. I am trying to get more control over my film because there were some decent shots that turned out terrible because of low contrast, under/over exposure/development etc. I would like to ensure that in the future I have printable negatives, even if their content may be mundane.

 

[Michel Hardy-Vallée]

I use the step wedge as a tool for relative, rather than absolute, measurements.

Contact print it on a light-sensitive material in a manner that will give you a few fully black steps and a few fully white steps on either side of the wedge. That way you know you have exposed the whole range your material is able to hold.

What for? Different things. For now it shows me the relative contrast of the papers I use. For instance, G2.5 of one variable contrast paper is more like G3 of one other graded paper. If you expose two different materials for the same time, you can also infer speed differences in stops (3 steps = 1 stop).

That has shown me, for instance, that Arista APHS litho film developed in print developer has about the same contrast as a grade 3 paper, and is about a stop faster with my setup. It has also shown me that I really need a powerful developer like stock dektol to extract enough contrast from Eastman 2302 if I want to make B&W positive transparencies.

Use it smartly instead of slavishly measuring densities, hoping to achieve an xyz value for Zone -6 because AA said so.

 

[Ole]

I used my step wedge to calibrate my papers, not film or development.

I put the step wedge in the enlarger (I have a 5x7" one), and printed it on all my different papers at a fixed exposure time. Combined with the Ilford EM-10 meter I now know that if I adjust the illumination to put tone X at reading Y, paper Z will give That tone scale at 15 seconds exposure, as well as where highlights and shadows will fall when printed that way.

It was a lot of paper with lots of different filtrations, but at least now I know what I'm doing (wrong).

Except in situations of extremely high contrast, I give all negatives exactly the same development. I decided that if I like a low-contrast scene well enough to photograph it, i will probably prefer a low-contrast print too. So I expose for the shadows and develop for the tonality, unless that would put the highlights way beyond reason - 14 stops, and I'll try it normal but probably expose a second sheet for compensating development.

 

[Nick Zentena]

I used my step wedge to:

1) Calibrate my densitometer. Much cheaper then the one sold by the densitometer company.

2) To figure out the contrast range my colour head could give with VC paper. It's amazing how soft it could go.

 

[jovo]

Well ian I looked through my prints and negatives today an i was really amazed at how inconsistant they were. I am trying to get more control over my film because there were some decent shots that turned out terrible because of low contrast, under/over exposure/development etc. I would like to ensure that in the future I have printable negatives, even if their content may be mundane.

It sounds more like a problem with inconsistent metering and erratic development than one that needs a step wedge to address. Get used to 'placing' zone 3 wherever you want detail to be in the low values, and seeing where zone 7 falls thereafter. Zone 7 should still contain detail in the high values where you wish to retain such detail. Adjust development accordingly.....more to expand, less to contract. If using T grain films, there's not a lot you can change that'll make a difference anyway. Be consistent with your development time then, and expect the film to be rather forgiving if you're a bit off.

We have a number of step wedges none of which I have ever used. My wife uses them to calibrate her digital negatives for her photogravure work. Even discussing the log variables in that process makes my hair hurt. Mount and mat your itty bitty little wedge, and tell your friends you've made a post modern artistic breakthrough. They'll be baffled and impressed; your hair will relax and your BP will drop significantly.

 

[Donald Miller]

Darin,

I am going to depart from the answers that you have received thus far and tell you one of the ways that a step wedge can be used to gain repeatability in your process.

In spite of what others have said, there are any number of noted good photographers that use the step wedge to determine the exposure scale of the paper that you print on. You won't need to go through countless printings of different paper grades because the final print begins with the paper characteristics...not the density range of the negative as some would advocate.

Print your step wedge on your chosen paper with the light source that you use...you don't need to enlarge the step wedge...in fact contact printing it onto your paper will work just fine. The wedge you have probably has a maximum density of 3.04 if it is anything like those that I have seen...The .04 comes from the transmission density of the clear substrate itself. Each step will be .15 of density and thus two steps will relate to one stop of density presented to the paper during exposure.

It is most accurate to measure the reflection density of the wedge after the paper is exposed, processed and dried. However, you can get fairly close by simply seeing how many steps you can ascertain have different tonal renditions when the paper is dried.

Let's say that you find that at grade two filtration on your paper, you find that the step wedge has 9 steps that are clearly different from each other...that would mean that your paper, with your light source has a exposure scale of 1.35. Once this is determined, you can then determine the density range that your negatives need to have to match the scale of the paper. A point worth mentioning here is that not all papers have the same exposure scale at a given contrast grade or filtration. A little work here will save you a heck of a lot of wasted time, frustration, and wasted paper making substandard prints.

I use BTZS as my metering and developing procedure...but you can use the Zone system for the same thing if you want. If you then expose and develop your film consistantly you will be able to have much more repeatability in your process. You won't even need one of those fancy schmanzy enlarger exposure meters to tell you what density goes where in making the print. If your negative has a minimum density of .16 and a maximum density of 1.31 (for instance) you will find that your enlarger exposure times are pretty much a matter of rote.

Now wasn't that easy? No headaches, no countless tests of exposure and you don't even need to throw your step wedge away because you will find that it really does work very well when it is used as I have described. Good luck and good light to you.

 

[darinwc]

"Mount and mat your itty bitty little wedge, and tell your friends you've made a post modern artistic breakthrough. They'll be baffled and impressed; your hair will relax and your BP will drop significantly."
I love you Jovo!

 

[darinwc]

Donald,
Thank you for your in-depth reply. It will be some time before my darkroom is useable again so I will have to wait a while before I can test paper. (i can develop film in a daylight tank)

I have copies of BTZS (Beyond the Zone System), The Negative, and 2 other large format books that discuss film or paper testing. They all have different ways to do it.

On first glance the advice i am reading says to test your paper first/only, which is confusing to me because I would think that in order to get a fine print you would need to start with a good negative. And to be honest I have no idea what a good negative is supposed to look like.

 

[Michel Hardy-Vallée]

And to be honest I have no idea what a good negative is supposed to look like.

Not an easy thing to figure out, but a good negative is one that fulfills your purpose (*think relative!*), no more and no less.

If you're doing regular continuous-tone photography on silver-gelatin, then it's usually a negative that prints easily on grade 2 (120 and LF) or grade 2.5-3 (35mm). That means almost no dodge and burn, and details in the highlights and shadows for a straight print.

This photo in my gallery:
(there was a url link here which no longer exists)

just prints straight from the negative. Why?

First because the contrast of the scene is not beyond the recording ability of the film (Efke 100 in Rodinal).

Second because the exposure (average metering on my Spotmatic) was just enough to secure minimal shadow detail, but not so much as to push everything near the shoulder.

Third because development is just enough to give proper contrast (thus proper tone separation and avoid blocked highlights).

Fourth because I took some time to figure out the exact grade I needed for my paper to print it, after trial and error.

But then, if my style were different, I might need an underdeveloped negative, and grade 4 paper. Cindy Sherman needed reticulation, "soot and chalk" contrast, and bad light to accomplish the look of her Untitled Film Stills.

If you want to know what a good negative is, you need to set a purpose first. Then you work backwards to optimize your results for it. In my case, I know what's a bad negative: that's the one I spend hours and hours not getting anything nice out of them because they were underexposed/overdevelopped/taken in the wrong light/etc.

 

[vet173]

Ole gave you the best tidbit. Use it to test your PAPER. Donald told you what I would say myself. ( At the rate I type the thread would be two days old to get it done) I did not own a step wedge for 35 years. When I got one I made about five test prints of each. One for a base and others for toning to see what happens. I was surprised that Ilford MG IV had the most range but others had different wonderful relationships in the mid range. It was just a chore, but the dividends will be well worth the effort. I also use the BTZS method. If you feel masochistic go ahead and get ansel adams " The Negative " be sure to get the hardback so you can use it instead of the wall to beat your head against. You will at some point come to the realization that one stop one zone has no basis in reality. Then get the BTZS book, equally frustrating to read at first, but will give you the ability to get real results. You will also KNOW what the result will be BEFORE you click the shutter. Your negs will be exactly what you want. You have to make the negs fit the paper. The paper step wedge test tells you where to put the neg. ansel was ok but he was no Brett Weston. Hell, check the gallery here and you will see stuff that kicks ansels' ass.

 

[ic-racer]

There are a number of ways to use the step wedge, some of which might make your processing easer and others are just for 'curiosity.'

Currently, the most common thing I use the step wedge for is to expose film in a sensitometer to get process control strips (which are read with a densitometer). Since I use rotary processing, I need to 'figure out' a new time for each film/developer combo I am using. Using the control strips can help zeroing in on a development time that can yield printable prints. So, if I know a contast index of about .6 to .7 gives me good printable negatives I can prcess the 'unknown' to that same contrast index as a starting point (of course one can always process 'pictures' rather than step wedge images and trial and error print them with the same or better results). Maybe a time-saver, maybe 'more trouble than it is worth' but that is what I am currently doing.

The suggestions of using the step wedge for printing paper gave me some ideas. I don't have a reflection densitometer, but one could just get a total range from black to white, rather than a nice sigmoid curve that a reflection densitometer would give.

Personally I have always felt that characterizing the contrast of papers was like characterizing the speed of papers: not that useful to ME. Because I am going to do test prints for the exposure and I also have a way of doing test prints to zero in on the filtration for the contrast too.

Out of curiosity, though, I did get an idea of seeing what the setp wedge will look like on paper for some of the points on this graph that I had previously posted:rolleyes: . So, on the X-axis it could have the density range (as read from the step wedge) in addition to the contrast number assigned by Ilford. (there was a url link here which no longer exists). Again, just fine tuning or 'interesting to know' stuff.

Ansel played down sensitometers/densitometers/PH probes, but he had all those things and used them. It seemed like he used those things to satisfy his curiosity and to keep him from making any misleading statements in his books.

It reminds me of a book that was popular many years ago about hundreds of uses for gray 'Duct Tape.' Yes, there many ways to use the tape, but when one looks around one's house, you probably use very little of it in daily living. Likewise a book could be written on hundreds of uses for a step wedge, but in practical photography you may find you don't really use it much at all.

Of course if your are a Duct Tape fanatic, the above may not hold true.....

 

[Chuck_P]

Ansel played down sensitometers/densitometers/PH probes, but he had all those things and used them. It seemed like he used those things to satisfy his curiosity and to keep him from making any misleading statements in his books.

AA played down sensitometers and ph meters, but he absolutely advocated the use of a densitometer.

 

[dancqu]

I've used my step wedge to calibrate my
$29 EM-10. The EM-10 can now be used
in conjunction with an enlarger to serve
a projection densitometer. Dan

 

[smieglitz]

The Ansel Adams Guide: Basic Techniques of Photography by John Schaefer (but I don't remember if it is Book 1 or Book 2 of the series) has an explanation of using the step wedge to test film and an edited version of Ansel's Zone System within its pages. Schaefer has lifted some of Ansel's photos, charts and text and rewritten Adams' Basic Guide books to a much more readable version. Using excerpts from the Negative, The Print, etc., reordering and supplementing them, he's come up with a tome that is much easier to understand than Ansel's original writings.

And, he explains very clearly how to use the step wedge for testing 4x5 film. With his method and about 6-7 sheets of film, I suspect one could get an almost immediate understanding of their personal film exposure and development requirements. IIRC, the key to the method is taping the stepwedge to a sheet of film and then exposing the film to an evenly-lit Zone X target. Doing this same exposure to several sheets but varying the development of each gives all the data needed to figure out N, N+, N++, N-, N-- very quickly.

As far as using the stepwedge on print materials, it is the place to begin the entire calibration process. If you determine a print exposure through the stepwedge gives a certain tone at a certain step (and thus density), you can translate that to practical data such as an average middle gray (zone V) density is 0.65 for that paper. Then, you can test a film, determine its proper speed, and develop so that your middle gray exposure matches the density (0.65) you need to reproduce the tone correctly on the paper you are using. Maybe you will find zone VIII is 1.20 above fbf for your materials, but maybe not. The step wedge tells you exactly which density you need for any given tone. Then you go ahead and run the film tests to tailor the results to your print materials (whether they are silver-gelatin commercial papers, hand-coated platinum, etc.).

Joe