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Thread: Multiple Test Zones on one Sheet

  1. #1

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    Multiple Test Zones on one Sheet

    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

  2. #2

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    Re: Multiple Test Zones on one Sheet

    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):

    Click image for larger version. 

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  3. #3

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    Re: Multiple Test Zones on one Sheet

    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

  4. #4

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    Re: Multiple Test Zones on one Sheet

    Quote Originally Posted by kq6up View Post
    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 nš1 will be (nearly) 5 stops overexposed and step nš11 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.

  5. #5

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    Re: Multiple Test Zones on one Sheet

    Chris,

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

    Mike

  6. #6

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    Re: Multiple Test Zones on one Sheet

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

  7. #7

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    Re: Multiple Test Zones on one Sheet

    Quote Originally Posted by Pere Casals View Post
    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):

    Click image for larger version. 

Name:	s-l500.jpg 
Views:	23 
Size:	45.4 KB 
ID:	196624
    Does the edition of the book matter that much?

  8. #8

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    Re: Multiple Test Zones on one Sheet

    Quote Originally Posted by kq6up View Post
    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...

  9. #9

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    Re: Multiple Test Zones on one Sheet

    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

  10. #10

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    Re: Multiple Test Zones on one Sheet

    Quote Originally Posted by kq6up View Post
    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

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