Mythbuster "You have to expose for the shadows and develop for the highlights"

Discussion in 'B&W: Film, Paper, Chemistry' started by ic-racer, Mar 4, 2008.

  1. ic-racer

    ic-racer Member

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    Here the first in a potential series of 'Mythbusters' dealing with topics of potential interest to photographers. :munch:

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    Mythbuster "You have to expose for the shadows and develop for the highlights"

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    Myth or Fact?

    Let's follow Bill and Sam through a "Fred Picker Inspired" basic photography course to find out.

    Both students load their identical, perfectly functioning cameras with identical TMY and shoot a series of test exposures, sharing the instructor's Pentax spot meter.. Bill listens closely to the instructor and makes a series of Zone I exposures at EI 6, 12, 25, 50, 100, 200 and 400.

    Sam gets confused with the aperture dial, and makes a series of Zone VIII exposures at IE 6, 12, 25, 50, 100 and 200 and 400.

    They develop their properly labeled film for 6 minutes in the same tank.

    Bill listens to the instructor and zeros the densitometer on his "film-base-plus-fog" and identifies the frame that has 0.1 log more DENSITY. The frame he winds up with was the Zone I frame shot at EI 200.

    Sam gets confused and zeros the densitometer to his FOGGED ( daylight-exposed) film base, then chooses the frame that has 0.1 log units more TRANSMISSION. The frame he winds up with was the Zone VIII frame shot at EI 12.

    With their new exposure indexes, Bill (EI 200) and Sam (EI 12) both make some Zone VIII exposures on two rolls of film each. Sam gets confused with the aperture ring, however, and makes exposures that have eight stops LESS exposure (essentially Zone I). Both develop their properly identified film in the same tank for 6 minutes.

    Bill and Sam head to the darkroom to test the development time. Bill places a piece of blank film-base-plus-fog into the enlarger and makes a test exposure. He identifies the first strip that is totally black and records the exposure.

    He then places his Zone VIII exposure (shot at ei 200) in the enlarger and exposes it for the same time as indicated in his black test exposure. He covers 1/2 of the paper during the exposure. He processes the print and notices a totally white sheet of paper. He concludes his Zone VIII is too dense and makes a note to decrease development of the next roll by 20%.

    Sam gets confused and places a piece of FOGGED (daylight-exposed) film base in the enlarger and makes a test exposure. He identifies the first strip that is totally white and records the exposure.

    He then places what he thinks is his Zone VIII frame in the enlarger. It really is a Zone I exposure shot at EI 12. He gets confused and exposes 1/2 of his test paper to white light, then exposes the other half to his Zone I frame at the indicated time. He processes the print and sees a totally black sheet of paper. He remembers correctly the instructor saying that if there is no difference in the two sides of the test print then decrease development. He makes a note to decrease development of the next roll by 20%.

    Bill and Sam take their second test roll that they had previously exposed above. They realize they are both decreasing development by 20% and the develop their properly identified film together in the same tank for 5.5 minutes.

    Bill repeats his Zone VIII frame test and gets a test print that is half pure white and just begins to show some density on the other side. He concludes that his development is correct and he is ready to start shooting pictures.

    Sam repeats his Zone VIII frame test (which he actually shot at Zone I) and gets a test print that is half pure black and is just slightly lighter on the other half. He remembers the instructors saying that if you can just barely see the difference in the two sides of the print that the development is correct. He concludes that his development is correct and he is ready to start shooting pictures.

    The instructor stands outside in bright sunlight holding a gray scale. Both Bill and Sam photograph him at the same time with their tripods next to each other. Bill uses the spot meter to measure the shadowed face of the instructor and places it on Zone III at EI 200. He makes his exposure (1/200th at F16). Bill then checks the sunlight white shirt of the instructor and it falls right on Zone VIII. He concludes the scene should work well with the development time he had just established.

    Sam gets confused and uses his spot meter to measure the sunlight white shirt of the instructor . He places the shirt on Zone VIII and makes his exposure at EI 12. His exposure is 1/12th of a second at F16. He then checks the shadowed face of the instructor and it falls right on Zone III, so he concludes the scene should work well with the development time he had just established.

    Again they develop their properly identified film together for 5.5 min. and go to the darkroom to make their best prints. They both submit their best prints to the instructor, but they forget to put their names on the back of the prints.

    They turn in their notebooks to the instructor and he sees that Sam got it all backwards. He EXPOSED FOR THE HIGHLIGHTS AND DEVELOPED FOR THE SHADOWS!:surprised: Obviously, the instructor would be able to tell which print was Sam's and which was Bill's.

    Right?

    (prints to follow...)
     
  2. jim appleyard

    jim appleyard Member

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    Sam ain't the sharpest tool in the shed, is he?
     
  3. JBrunner

    JBrunner Moderator Staff Member Moderator

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    Made my day.
     
  4. Christopher Walrath

    Christopher Walrath Member

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    My head hurts. Attempting second half now.
     
  5. Christopher Walrath

    Christopher Walrath Member

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    Naw, early morning on its way. I'll do da tinking thing later.
     
  6. RoNinHeart

    RoNinHeart Member

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    Thank you for changing my name to Sam...
     
  7. gainer

    gainer Subscriber

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    I'm confused about how that old adage got to be associated with the Zone system, which didn't come until later. I knew the rules of the ASA system, and knew that it boiled down to a standard exposure meter that was designed to put the scene brightness that it measured a factor of 10 above the film's "inertia". If I knew my camera well enough, I could set the meter for 10X the ASA speed of the film I had and read the scene brightness at the darkest point where the detail was important. Since I used roll film only, I could not afford the luxury of developing each frame, so I used hard or soft paper and various printing tricks if necessary. If I had used sheet film, or had a whole roll with the same SBR, I could develop the negative more or less to suit. So, all one had to know was the ASA speed of the film, how to multiply by 10, and the exposure reading of the significant shadow.
     
  8. Ray Heath

    Ray Heath Member

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    did you make a point or ask a question?

    i stopped reading after the third time you made fun of Sam
     
  9. jd callow

    jd callow Moderator Staff Member Moderator

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    Yeah I was feeling kind of bad for sam too
     
  10. sun of sand

    sun of sand Member

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    Yeah, really! lol
    As long as they both make it on the train I don't think it matters how old Bills apples are.
     
  11. nworth

    nworth Subscriber

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    The really important thing is that you have to give enough exposure to the darkest thing of interest in the scene to make it register on the film (expose for the shadows). Development affects the shadows more or less the same regardless of extent (OK - extreme underdevelopment will underdevelop them too, but the shadows are more or less unaffected by the degree of development). The highlights are affected by development, however, and overdevelopment caused them to block up badly on older films. That's where the "develop for the highlights" came from. The situation is not so bad with modern films, but sticking to the adage still makes your printing easier. The zone system uses development to control contrast, which is a related but quite different thing. Since you can't avoid the "expose for the shadows" part and the zone system uses adjustments in development, confusion was bound to happen.
     
  12. fhovie

    fhovie Subscriber

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    Good old rules of thumb did not happen by accident. There is no harm in testing them but the wisdom of "expose for the shadows" is firm - You just can't get them back if they are not there. I guess the whole thing reminds me of my kids who figure that if it is established knowledge, it must be wrong - lets do the opposite. Then in their thirties they say - oh, gee, I guess the old rules were kind of right after all. Usually rules of thumb are shortcuts that savvy people use to get to technical excellence quicker by understanding them better rather than wasting time refuting them.
     
  13. Ian Leake

    Ian Leake Subscriber

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    Umm, I must admit I couldn't cope with doing all the maths, but it sounds like a carefully crafted example of how reliance on good fortune can occasionally produce good negatives. Wouldn't it have all fallen apart for poor Sam if the instructor's shirt had been blue rather than white? Bill, of course, would have been fine.
     
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  15. richard ide

    richard ide Member

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    What's funny?
    My tests turned out exactly the same way.:D
     
  16. eddym

    eddym Member

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    I got lost trying to follow all Sam's screwups.
    Meanwhile, Charlie shot XP2 at box speed and had it developed at Walmart.
    :wink:
     
  17. Andy K

    Andy K Member

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    I just like ta tek em pichurs.
     
  18. cowanw

    cowanw Member

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    I kind of like Bill
    Regards
    Bill
     
  19. Thomas Bertilsson

    Thomas Bertilsson Subscriber

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    Sigh... Make sure you get enough light through to the film to record shadow detail. Develop for an appropriate amount of time to get decent highlights. That's all there's to it, really. Why should it not be true? It's what film developing is. And, as a bonus, you can tweak it to how you like it.
    - Thomas
     
  20. tim_walls

    tim_walls Member

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    Well quite. If it's not recorded on the film, you're not going to recover it in the darkroom after all.

    The reductio ad absurdem of the opposing point of view is to just point the camera at the scene and then not open the shutter at all. While on the one hand I can offer a personal guarantee that you won't burn out your highlights, I would also suggest that it doesn't matter what you do in the darkroom, you ain't going to recover any shadow detail either...
     
  21. ic-racer

    ic-racer Member

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    I was cracking up while writing it. I don't want to offend anyone that relates to either one in the story, but in a way Sam in pure genius. He demonstrates Einstein's theory of relative motion! Seriously, he does!

    I understand that only the "Zonies" are probably familiar enough to follow the story, but they may not believe the conclusions, whereas straight forward shooters may not be able to understand what Sam is doing. So I'll explain it all in the end, so that everyone can see the humor and serendipity :wink:

    But on to the pictures...
     
  22. BWGirl

    BWGirl Member

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    You know... I think Bill & Sam would be much happier if they just go out & burn a roll of film without all the freakin' thinking! Sheesh! :wink:
    (Stop picking on Sam. You will bruise his ego and make him turn to digital photography.)
     
  23. Ian Leake

    Ian Leake Subscriber

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    Sam needs to get an 8x10 - that'll cure him of his slapdash habits...
     
  24. panastasia

    panastasia Member

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    I see it this way:
    Kids in their adolescents feel they know more than their parents and then, by the time they reach the age of 25-30, they wonder how their parents suddenly became smart..
     
  25. Steve Smith

    Steve Smith Member

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    I quite like that attitude. If someone says to me "you can't do it like that...." my immediate reaction is "why? What would happen if I did?".


    Steve.
     
  26. ic-racer

    ic-racer Member

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    Here are the pictures.

    The pictures came from Todd and Zakia, they were showing results from a similar experiment and published it in the book.

    A)[​IMG]

    B)[​IMG]