Switch to English Language Passer en langue franšaise Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 75,237   Posts: 1,660,017   Online: 937
      
Page 6 of 12 FirstFirst 123456789101112 LastLast
Results 51 to 60 of 114
  1. #51
    markbarendt's Avatar
    Join Date
    May 2008
    Location
    Beaverton, OR, USA
    Shooter
    Multi Format
    Posts
    5,984
    Blog Entries
    3
    Images
    19
    Agreed Michael,

    It was interesting for me when I started to grasp the concept of latitude and that we didn't actually ever print everything available from a given film/frame and that our prints generally only represented a fraction of what a given negative held.

    When I came back to film I started with slides and was coming from digital where I loved shooting jpeg. It was really tough coming to grips with the thought that what I did with the camera/film only had a general relationship to the print, not an absolute one. That the print I just made was just one possible interpretation of many.

    With this realization I started testing the latitude and was amazed just how far one can stray (in EI terms) and still make nice prints, just as expected. Finding the limits of that range, for any given film/developer combo, allows for a great amount of creative freedom and spontaneity without worrying about whether or not I got something workable. It also moved me away from thinking my camera work had screwed my print, at least in most cases.
    Mark Barendt, Beaverton, OR

    "We do not see things the way they are. We see things the way we are." Ana´s Nin

  2. #52
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    24,460
    Images
    65
    Michael, the same arguments hold for both B&W and color as they are generally made to the same overall aim curve shape. The big difference is that color begins to "go off" due to crossover and other effects if you go too far over or under.

    PE

  3. #53

    Join Date
    Dec 2009
    Location
    Monroe, NY USA
    Shooter
    Medium Format
    Posts
    116
    Assuming your metering is accurate, make sure you're not using different ISO because you are not developing the film properly. Temperature control in the developer step is important - the solutions may be at the right temperature but if the tank/reels/film are different you won't be developing at the right temperature. Also, your thermometer should be calibrated to a color thermometer to get the right temperature.

    Since employing good temperature control (bringing the tank/reels/film to temperature and maintaing it in a water bath, and using a thermometer calibrated to a color thermometer), results shooting at box speed and developing according to instructions have been excellent.

  4. #54

    Join Date
    Jan 2004
    Location
    NYC
    Shooter
    Medium Format
    Posts
    1,238
    I run my own speed tests to standardize my exposure technique n printing technique, paper/dev film/del combos, to give me the range of tones that fit my style. I never pay sny attension to box speeds or if my meter jives with another! Its my own standards to fit my equipment n methods.
    Anyone can make a Digital print, but only a photographer can make a photograph.

  5. #55
    markbarendt's Avatar
    Join Date
    May 2008
    Location
    Beaverton, OR, USA
    Shooter
    Multi Format
    Posts
    5,984
    Blog Entries
    3
    Images
    19
    Quote Originally Posted by paul ron View Post
    I run my own speed tests to standardize my exposure technique n printing technique, paper/dev film/del combos, to give me the range of tones that fit my style. I never pay sny attension to box speeds or if my meter jives with another! Its my own standards to fit my equipment n methods.
    In the beginning, did you start somewhere close to box?
    Mark Barendt, Beaverton, OR

    "We do not see things the way they are. We see things the way we are." Ana´s Nin

  6. #56
    Stephen Benskin's Avatar
    Join Date
    Jan 2005
    Location
    Los Angeles
    Shooter
    4x5 Format
    Posts
    1,289
    What makes people confident that their testing method is yielding reliable results?

  7. #57
    yurisrey's Avatar
    Join Date
    Feb 2011
    Location
    New York Metro Area
    Shooter
    Multi Format
    Posts
    260
    Quote Originally Posted by Stephen Benskin View Post
    What makes people confident that their testing method is yielding reliable results?
    I guess it's rather subjective to a point. For my serious work and non-experimentation, I mainly do reversal and follow the box speed at first. If I personally don't find the rated speed to my liking, I assign it my own EI. But, I always make it a point to follow the manufacturer's specs for processing to the letter, this way I don't introduce any other variables that may cause inconsistencies.
    "The real work was thinking, just thinking." - Charles Chaplin

  8. #58
    Bill Burk's Avatar
    Join Date
    Feb 2010
    Shooter
    4x5 Format
    Posts
    4,083
    Images
    51
    Sorry to bring up a new argument in the conclusion... But the first debate I won in high school was because I had a suprise argument.

    The Delta-X Criterion, which I use for my own speed determination (so I subscribe to it but I want to explain something)... is based on the agreement that 0.3 Gradient is the appropriate speed point... Based on the study of The First Excellent Print.

    Zone System speeds are NOT based on the study of the The First Excellent Print. So there is no reason except coincidence that the speeds even closely relate.

    The First Excellent Print is based on people who viewed prints and pointed to the ones they liked. Built into this study is a Standard Observer's Opinion that "some" of the shadow detail is not important.

    The biggest difference between this and the Zone System is... You will never hear anyone who uses the Zone System saying that shadows are not important.

  9. #59

    Join Date
    Sep 2006
    Location
    UK
    Shooter
    35mm RF
    Posts
    4,766
    Quote Originally Posted by Bill Burk View Post
    Sorry to bring up a new argument in the conclusion... But the first debate I won in high school was because I had a suprise argument.

    The Delta-X Criterion, which I use for my own speed determination (so I subscribe to it but I want to explain something)... is based on the agreement that 0.3 Gradient is the appropriate speed point... Based on the study of The First Excellent Print.

    Zone System speeds are NOT based on the study of the The First Excellent Print. So there is no reason except coincidence that the speeds even closely relate.

    The First Excellent Print is based on people who viewed prints and pointed to the ones they liked. Built into this study is a Standard Observer's Opinion that "some" of the shadow detail is not important.

    The biggest difference between this and the Zone System is... You will never hear anyone who uses the Zone System saying that shadows are not important.
    Sorry shadows are not important if you are shooting slides.

    If you are shooting negatives if you get zone 1 below the halide fog it is not present so no detail.

    If zone1 is into the toe it will be more difficult to print unless you like dark prints with compressed shadows.

    Some people do like that and it can add emphasis.

    Until 1960 the box speed had a safety factor of 2.5 stops, post 1960 this was reduced to 1.5.

    HP3 boxes changed from 200 ASA to 400.

    Some manufacturers don't put the ISO speed on the box, eg Forma and I'm picking Forma as a good example.

    Forma as well provide a data sheet for each film type with the 'ISO' speed for developers you might use like eg DK76 as little graphs of fog, contrast and speed and temperature.

    If you look at the graphs it tells you a lot even if you are never to use Forma.

    Id already discovered that the Formapan 100 was nearly as fast as the 400 before I looked at the graphs. I should have looked at the graphs first.

  10. #60

    Join Date
    Sep 2002
    Location
    Oregon and Austria
    Shooter
    4x5 Format
    Posts
    952
    Quote Originally Posted by Stephen Benskin View Post
    ... It's a very common misunderstanding. Film speed isn't determined by density because negative density by it self isn't relative to print quality. Film speed is determined by gradient. The fixed density of the ISO standard is a short cut to determining the fractional gradient point. As per Nelson, the fixed density method is only accurate when the contrast falls within the ISO contrast parameters. Otherwise you need to plug ΔD and Δlog-H into the Delta-X equation because with increased and decreased negative development, the fixed density method is less accurate. You're probably conflating it with how an increase in film density usually is accompanied by a higher gradient. This isn't always the case and definitely not to the same degree in different film types. This is all explained in Simple Methods of Determining the Fractional Gradient Speeds of Photographic Materials by C.N. Nelson and J.L. Simonds. If the OP really wants to understand what the REAL ISO is about, this is the paper.

    As for a personal EI, whatever makes you happy.

    The statement that very manufacturer deciding for themselves what the contrast for the standard should be is patiently wrong. The contrast parameters are clearly defined in the standard. Any variation and the ISO prefix cannot be used.
    Stephen,

    Obviously I'm working from an over-simplified model and using the terminology imprecisely...

    But, for the sake of clarification, when I develop, say N-2 in order to accommodate a rather high subject brightness range, am I not changing the gradient and therefore the effective speed of the film? Or would you say that this is outside the parameters of ISO testing standards and simply does not apply?

    If the latter, then what would you call the E.I. I need to use for N-2, simply E.I.? Is that not somehow "film speed" as well? "Effective speed" maybe?

    In any case, I feel we need some more easily-accessible and usable terminology to deal with changes in film response with different development schemes. Maybe you have some suggestions in this department that could be simply understood and utilized by non-specialists while avoiding conflation, ambiguity and confusion at the same time; something in Feynman vein.

    I never meant to imply that manufacturers can decide for themselves what the contrast standard for ISO determination is. However, it does seem that they can choose a developer, so there is no fixed standard in that department. Plus, there is a growing practice, especially for films designed to be used in low-light situations to have a number on the box, i.e., "box speed," that is not the true ISO speed (Ilford Delta 3200, et al.). This just adds to the confusion IMO.

    And, although I'll more than grant you the point that ISO is a strict and reliable value arrived at by rigorous methods, I still find a bit of a disconnect about how it is practically applied. Certainly, you would not advocate my using the film ISO as my basis for metering for an N-2 negative... or when using a developer that is known to not deliver full ISO speed. Or would you?

    I've spent a lot of time testing to arrive at development schemes that allow me to accommodate scenes with varying subject brightness ranges. While not completely quantified and constantly being refined, I feel I am much better off giving a tested and field-proven amount of increased exposure and reduced development for high SBRs and the converse for low SBRs. I have made Zone Rulers a lß Zakia and White for all my development schemes and am fairly confident using them. Should I really be questioning whether my testing method "is yielding reliable results"? Are the Zone System and BTZS tests unreliable?

    All the above in the spirit of refining my knowledge and technique with thanks in advance for taking the time to answer.

    Best,

    Doremus



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  Ś   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin