Multiple Test Zones on one Sheet

[kq6up]

The idea of exposing 11 4x5 sheets of film to make a sensiometric curve makes the cheapskate in me cringe. Have any of you successfully exposed 4x5" with all 11 Zones on one sheet. I need the patches to be about .5cmx.5cm to easily find/read them with my densiometer.

Suggestions welcome,
Chris Maness

[Pere Casals]

Buy a Stouffer T2115 Transmission 21-Step, $8 You make a contact copy with it on film, so you have all zones in one shot. From a single sheet you may cut several strips, so you need a single sheet to make say developments.

From your question, I guess you would find interesting this bible (ebay, $20):

196624

[kq6up]

Thanks. I have one for my densiometer. I thought about that, but my hesitation was:

What do you do to get within a ballpark for the exposure? (in other words how do you translate to EV for exposure index/camera use etc...?) Do you use an enlarger to make the contact copy?

Chris

[Pere Casals]

Thanks. I have one for my densiometer. I thought about that, but my hesitation was:

What do you do to get within a ballpark for the exposure? (in other words how do you translate to EV for exposure index/camera use etc...?) Do you use an enlarger to make the contact copy?

Chris

Hello Chris,

First, let me recommend again to read the Phil Davis book for refined methodology.

Usually film calibrations are made with the enlarger, 1 second exposure is commonly used because if shorter you have heating transitories in the lamp filament and if longer you have LIRF, but with an accurate timer and LED illumination shorter exposures can be used.

A nice film calibration/plots has absolute Log H units in the Horizaontal axis, so we use a Luxmeter ($15, with 0.01 Lux precision).


To make things easy, you may also shot the calibration with the camera, I do it in the next way:

Use an over exposure of about 5 stops, in your holder you have a film strip "glued" on the holder septum and the stouffer on it. Each step is 1/2 stop less exposed, so Patch nº1 will be (nearly) 5 stops overexposed and step nº11 will be correctly exposed.

A way to do that is making a sort of pocket with cardboard than can take the film strip and the wedge. Then you spray 3M Re Mount glue in the back of the pocket to place it on the holder's septum.

You may also cut two Post-it strips to be glued in the septum with its wings taking the film+wedge...

Well... it's about placing the film+wedge in the holder, but you also require that checking shutter speed in accurate.

If your pocket is in shape then you may use the TP4x5-21 wedge model, that is 4x5, in that case you would place the wedge on a full sheet in the holder, provide both fit in the notches.

Regards.

[mpirie]

Chris,

Have a look at Alex Bond's website, and in particular: https://www.alexbond.com.au/film-speed-test/

Mike

[kq6up]

Thanks, Pere. That was a nice explanation, and I will get the book.

[kq6up]

Buy a Stouffer T2115 Transmission 21-Step, $8 You make a contact copy with it on film, so you have all zones in one shot. From a single sheet you may cut several strips, so you need a single sheet to make say developments.

From your question, I guess you would find interesting this bible (ebay, $20):

196624

Does the edition of the book matter that much?

[Pere Casals]

Does the edition of the book matter that much?


I have the 3rd edition that's in that image, I don't know if the 4th edition added something, but I can tell you that the 3rd edition is all you need.


In the first chapters there is some math about Logarithms, both the density and H exposure units you find in all film Datasheets are in those units, one may be liking math more or less, but I'd recommend you to make an effort to understand very, very well those concepts, read it several times if necessary and make a couple of the proposed exercises, with that you get a very solid base to understand the rest.

After practical sensitometry it teaches metering strategies, incident vs reflected is interesting, averages, etc but if the first part is well understood then you may use the spot meter to predict what density you'll have in the negative for any scene spot, with the exposure/development to select, then you also can guess how difficult would be the optic printing.

So first half is the theoric foundation you need for a solid understanding that will place you in command of the process, second half is practical and informative, very good for those that hate graphs and feel happy with recipes.


You don't need to understand practical sensitometry to make great images, at all, but it provides powerful resources.


You know, there are image hunters and image sculptors, many times an LF photographer is both. LF photography is more prone to custom developments and process control than smaller formats, our format is less agile and (usually)we shot less, after a log trip with the camera in the back we may not even plant the tripod because the light does not help, we have the phone for souvenirs :)

so... if you learn well that book you'll be in control, after that film/developers that are "magic bullets" are something different: resources you control.

Also read Darkroom Cookbook this is a principal knowledge that complements BTZS book.

In the near future that you may read Post Exposure PDF (http://ctein.com/PostExposure2ndIllustrated.pdf) and Way Beyond Monochrome if you are interested in optic priting.

Ansel Adams The Camera, The Negative and The Print are also a sacred trilogy, then Examples: The Making of 40 Photographs (Ansel Adams)

Well, these books are those I learn from.



If exporing old books, box speed changed in 1960, it was doubled without changes in the film, so (ASA) ISO 50 changed to ISO 100...

[kq6up]

Yes, I am very comfortable with the math involved. I am a college/high school physics instructor. I will pick up a copy. Thank you.

Chris Maness

[Pere Casals]

Yes, I am very comfortable with the math involved. I am a college/high school physics instructor.

Perfect, in that case this book is ideal for you, it speaks your language, you will get advanced concepts quite easy, and soon you will be in command to get what you want.

Sadly art is more difficult to explain :)

[kq6up]

Sadly art is more difficult to explain :)

So true! However, I do have a decent eye for a tech head nerd.

[Bill Burk]

I've written a bit on how to test film.

Here's a PDF free to download:

http://beefalobill.com/imgs/20150812%20CallingYourShot-DividedAttention.pdf

I noticed some URL's are broken since I wrote that so here's some updated links:

Resource page at Photrio
https://www.photrio.com/forum/resources/divided-attention.77/

Updated URL's
Recommended: Working idea - Zone System exposure - Time/CI darkroom
( https://www.photrio.com/forum/threads/working-idea-zone-system-exposure-time-ci-darkroom.84567/ )

Recommended: Enlarger -----> Sensitometer
( https://www.photrio.com/forum/threads/enlarger-sensitometer.92518/ )

Recommended: Great Sensitometer Shootout
( https://www.photrio.com/forum/threads/the-great-sensitometer-shootout.95837/ )

[Jim Noel]

In grad school I used three spare darkslides and made a hole in each one (located differently) so I could make 6 patches on one sheet. It worked well, and with 1/2 inch holes you could possible get 12 patches in three columns of four holes per column. It like take 8 darkslides to do it though.

I did similar and still have the dark slides. It only takes 3 old dark slides to make 6 exposures on a single sheet. each exposure is made to register Zone I at exposures varying by 1/3 stop. one is made at box speed,and the others are at 1/3 stop lower EI's. THe system has worked for me for about 60 years. I redo it with each new batch of film.

[Pere Casals]

I did similar and still have the dark slides. It only takes 3 old dark slides to make 6 exposures on a single sheet.

Jim, let me add another way. We may also do it with a single regular holder, we may fire the shutter many times, and each time we insert (say) 10mm more the dark slide, so we may make 12 exposures in a single sheet, the last one has the 12 exposures accumulated, the first one has a single exposure, we may provide an exponential exposure series...

I do that to find right exposures for paper negatives in pinhole, but it also may be used to test film.

[Doremus Scudder]

I guess I'll jump in here with my method, which entails using a filmholder with a darkslide marked in fifths (i.e., so one can make five exposures on one sheet of film by inserting the darkslide one-fifth of the way into the filmholder for subsequent exposures). I simply marked a darkslide with a Sharpie with lines; no drilling holes and ruining a darkslide required.

If necessary, I first determine a personal E.I. with a film speed test on one or two sheets of film. I don't do this much anymore, since experience has shown that if I just rate the film 2/3-stop slower than box speed and then keep notes any subsequent adjustments will be really small (1/3 stop usually).

For determining development times for N, and all N- and N+ times, I make Zone Rulers, using two or three sheets of film. My method is described in the attached document (from my field guide).

What's missing in the instructions is a discussion about finding the right subject for the tests. I like an evenly-lit textured wall (think stucco or smooth plaster). Using a real-life subject along with the camera and lens you use the most takes flare into account automatically and results in more usable (if less scientific) results.

Keep in mind, that the whole testing procedure is just to get us in the ballpark. Things like flare from uncoated or single-coated lenses in both camera and enlarger can make a significant difference in the low values, not to mention flare from light sources or bright areas in or just out of the image area.

Really, only consistent note-taking and making small adjustments can hone an exposure/development system. Using step tablets gives nice clear data, but they are often not relevant to what happens in actual taking situations.

Best,

Doremus

[Andrew O'Neill]

I made a Zone Board, as outlined in Gordon Hutchings', The Book of Pyro. It has worked well for me for over twenty years...

[Hans Berkhout]

Re the target for testing: an evenly lit board, wall etc can be created by using an Expo Disc on the camera lens. I use a 67mm disc which I pressed into an 67mm filter ring (discarded filter, glass removed). A second (smaller) Expo disc I hold in front of the exposure meter when taking the reading-which will be Zone V. I can make the required exposures even when it is 30 below outside: just stay indoors and aim camera at window. Make sure lens opening is such that vignetting cannot take place (look through ground glass cut off corner etc).

As an aside; the smaller Expo Disc I attached with black tape to a step-up ring fitting my enlarger lens, the prism side of the disc facing the negative. This set-up facilitates flashing of the printing paper, negative stays in place during the procedure while lens opening and/or timer are manipulated as needed.