Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,276   Posts: 1,534,778   Online: 823
      
Page 2 of 29 FirstFirst 1234567812 ... LastLast
Results 11 to 20 of 288

Thread: Film testing

  1. #11
    timbo10ca's Avatar
    Join Date
    Apr 2006
    Location
    Winnipeg, MB Canada
    Shooter
    Multi Format
    Posts
    543
    Images
    39
    Quote Originally Posted by Steve Smith View Post
    I have been looking at film testing information too and I found this quite interesting: http://www.halfhill.com/speed1.html
    and: http://www.halfhill.com/speed2.html


    Steve.
    I will definitely look into this.

    Thanks, Tim
    If only we could pull out our brains and use only our eyes. P. Picasso

    http://www.timbowlesphotography.com

  2. #12
    jstraw's Avatar
    Join Date
    Aug 2006
    Location
    Topeka, Kansas
    Shooter
    Multi Format
    Posts
    2,703
    Images
    42
    I have a film testing question.

    The Massive Dev Chart has a time of 50 min for FP4+ in 510-Pyro, 1:500 @ 21c. It doesn't have a time for HP5+ in the same regime.

    If the chart tells me that FP4+ and HP5+ should be developed for the same time (20 min) in some other dilute developer (it does for Rodinal 1:100, 20c) would it be a good starting point to use the same 50 min time for HP5+ for 1:500 510-Pyro?
    Lorem ipsum dolor sit amet, consectetuer adipiscing elit. In velit arcu, consequat at, interdum sit amet, consequat in, quam.

  3. #13
    Michel Hardy-Vallée's Avatar
    Join Date
    Apr 2005
    Location
    Montréal (QC)
    Shooter
    Multi Format
    Posts
    4,351
    Images
    132
    Tim, if you want a simple testing procedure that will at the same time fit your EI/dev time to your paper, try the following one:

    • Setup a plain target in even daylight. A big cardboard piece, say.
    • Meter it using the film ISO (let's say it's a 400): that's a Zone V
    • Close the lens cap and expose a blank frame
    • Open the cap and expose a series of frames from Zone 0 (closing 5 stops from meter read) until Zone X (opening 5 stops from meter read). There's a way to use only two shutter speeds and manipulate only aperture for this, let me know if you want to have it.
    • Process the roll under normal conditions with your chosen developer. Let's say for example that the manufacturers recommend 8 mins. Develop the roll at 8 mins.
    • Make a contact print using the grade you like for 35mm prints, let's say G3. The important thing is that the frame you shot with the lens cap on be a full black. Find the minimal time for it by gradually hiding the contact with an opaque card.
    • Now start analyzing
    • If the first distinct grey is on the Zone II exposure, you have a proper EI (400). If it's on Zone III, your EI is 200. If it's Zone I, your EI is 800
    • Count the number of greys between pure black and white. If you have seven, your dev time is OK. If you have six, that's N+. If you have eight, that's N-.
    • From now on, you can repeat the test a second time if you did not get a first grey on Zone II and seven greys (including Zone II).
    • Let's say that the first grey was Zone III, and that you had six greys. That's the likeliest result.
    • You're going to set your meter to 200 instead of 400, shoot the same sequence, and develop for 20% less than 8 mins (~6 mins), and do the contact sheet again.
    • That should get you close enough. You can do minor tweakings to nail it properly, but that's the gist of it. You would do the reciprocal process if your first grey was Zone III etc.


    The whole point of film testing is to get the dev time that will fit your scene into your paper, and the EI that will maximize the speed of your film. You don't even need a densitometer, because you are using the tones on paper as a guide. It's about what's on the paper first.

    All the systems you've read, whether it's "expose for the shadows, develop for the highlights," the ZS, BTZS, or Barry's heuristics, ARE ALL THE SAME DAMN THING! Everyone is using different methodologies, and have a more or less precise way of doing things, but, repeat after me, IT'S ALL THE SAME THING!

    Go in peace.
    Using film since before it was hip.


    "One of the most singular characters of the hyposulphites, is the property their solutions possess of dissolving muriate of silver and retaining it in considerable quantity in permanent solution" — Sir John Frederick William Herschel, "On the Hyposulphurous Acid and its Compounds." The Edinburgh Philosophical Journal, Vol. 1 (8 Jan. 1819): 8-29. p. 11

    My APUG Portfolio

  4. #14
    timbo10ca's Avatar
    Join Date
    Apr 2006
    Location
    Winnipeg, MB Canada
    Shooter
    Multi Format
    Posts
    543
    Images
    39
    Quote Originally Posted by mhv View Post
    All the systems you've read, whether it's "expose for the shadows, develop for the highlights," the ZS, BTZS, or Barry's heuristics, ARE ALL THE SAME DAMN THING! Everyone is using different methodologies, and have a more or less precise way of doing things, but, repeat after me, IT'S ALL THE SAME THING!

    Go in peace.
    This piece of wisdom struck me on the way to work this morning. I understand the zone system, but I never really thought about the basis for it- if a scene is contrasty/bright, you will be overexposing it and must therefore decrease development to fit it all into your film's exposure latitude. The opposite is true for a dull scene. How you "rate" your film is just a starting point for you to keep your blacks black.

    I will try your method- it is similar to the method I bungled by Steve Simmons, but I understand what it's doing. The only part I don't like about it is that it is subjective- "minimum black" and "first grey" can be too many things to my eye, and I'm trying to get as *exact* as possible so I can achieve the best negs possible for printing, which is what I perceive to be the hardest part. Exposing the neg is a calculated science, which is simple once you get the mechanics figured out.

    Thanks to you once again,
    Tim
    If only we could pull out our brains and use only our eyes. P. Picasso

    http://www.timbowlesphotography.com

  5. #15
    timbo10ca's Avatar
    Join Date
    Apr 2006
    Location
    Winnipeg, MB Canada
    Shooter
    Multi Format
    Posts
    543
    Images
    39
    Quote Originally Posted by mhv View Post
    [*] Make a contact print using the grade you like for 35mm prints, let's say G3. The important thing is that the frame you shot with the lens cap on be a full black. Find the minimal time for it by gradually hiding the contact with an opaque card.
    I assume you mean I use a piece of blank paper at a set height, do a test strip series until I see 1st pure black, and then expose the contact sheet at this time?

    If the first distinct grey is on the Zone II exposure, you have a proper EI (400). If it's on Zone III, your EI is 200. If it's Zone I, your EI is 800

    makes sense- if 1st grey is up at zone 3, you need more exposure time to bring it to zone 2

    Count the number of greys between pure black and white. If you have seven, your dev time is OK.

    you kinda lost me here, unless you are considering zone 1 and zone 9 to be pure black and white, which is what I thought zone 0 and 10 were supposed to be.

    If you have six, that's N+. If you have eight, that's N-.

    I'm trying to wrap my head around this one- If there are six greys when you expect seven, that's a contraction (therefore N-), is it not? Vice-versa for 8?

    From now on, you can repeat the test a second time if you did not get a first grey on Zone II and seven greys (including Zone II).
    Let's say that the first grey was Zone III, and that you had six greys. That's the likeliest result.
    You're going to set your meter to 200 instead of 400, shoot the same sequence, and develop for 20% less than 8 mins (~6 mins), and do the contact sheet again.


    You mean, repeat this test until you get your proper film speed and normal development for that speed? Suppose you determine this, how do you then determine what N+ and N- are?

    I apologize if I'm misunderstanding something obvious,

    Tim
    If only we could pull out our brains and use only our eyes. P. Picasso

    http://www.timbowlesphotography.com

  6. #16

    Join Date
    May 2006
    Location
    Northern Aquitaine
    Shooter
    35mm RF
    Posts
    4,913
    Quote Originally Posted by timbo10ca View Post
    The only part I don't like about it is that it is subjective- "minimum black" and "first grey" can be too many things to my eye, and I'm trying to get as *exact* as possible so I can achieve the best negs possible for printing, which is what I perceive to be the hardest part. Exposing the neg is a calculated science, which is simple once you get the mechanics figured out.

    Thanks to you once again,
    Tim
    Dear Tim,

    It's ALL subjective, too. The science of exposure is nothing like as exact as most people assume, and there's a lot of latitude you can fix in the darkroom.

    'First grey' is easy: if you can see it at a hard/discontinuous junction (neg density = 0.03 or above), you've got it. Going as high as 0.10 or even 0.15 will do no harm.

    Not sure what you mean by 'minimum black'. Presumably the minimum exposure required to get the maximum black of which the paper is capable. If it is that, it ain't difficult either.

    This won't alter the way you want to work, so in that sense it's useless, but you might care to look at 'Why we don't use the Zone System' in the Photo School at www.rogerandfrances.com, just for an additional perspective. It's free, so all it costs you as a couple of minutes of your time.

    Cheers,

    R.

  7. #17
    Michel Hardy-Vallée's Avatar
    Join Date
    Apr 2005
    Location
    Montréal (QC)
    Shooter
    Multi Format
    Posts
    4,351
    Images
    132
    Quote Originally Posted by timbo10ca View Post
    This piece of wisdom struck me on the way to work this morning. I understand the zone system, but I never really thought about the basis for it- if a scene is contrasty/bright, you will be overexposing it and must therefore decrease development to fit it all into your film's exposure latitude. The opposite is true for a dull scene. How you "rate" your film is just a starting point for you to keep your blacks black.

    I will try your method- it is similar to the method I bungled by Steve Simmons, but I understand what it's doing. The only part I don't like about it is that it is subjective- "minimum black" and "first grey" can be too many things to my eye, and I'm trying to get as *exact* as possible so I can achieve the best negs possible for printing, which is what I perceive to be the hardest part. Exposing the neg is a calculated science, which is simple once you get the mechanics figured out.

    Thanks to you once again,
    Tim
    You're most welcome! It took me a while to figure out how each testing procedure worked, but after reading a thorough article on BTZS it dawned on me that the fundamental principles are absolutely identical.

    If you want the primer on what's different beween ZS and BTZS, BTZS methodology allows you to calculate super-precisely N+0.85 or N-0.72, not just N+1 or N-1. Do you need this granularity in 35mm? I sure don't! Large format and alt process people on the other hand have probably the most exacting procedure for their exacting needs. In comparison ZS is a bit more granular than Barry's method.

    You'll see that minimum time for maximum black is very easy to get. Let's say you're making a test strip by moving the card over your neg+paper sandwich. You go 4, 6, 8, 11, 16 seconds (because you understand that linear darkening demands non-linear time increases, like the f-stops on a lens or a shutter).

    Suppose that 6 and 8s are distinguishable but that 8 and 11 are not. Ergo, 8s is your minimal time for maximum black.

    Regarding "first grey", you'll see that the difference between black and first grey is more striking than between two adjacent greys. So you don't need very acute eyes to see it. I think the reason has to do with how film builds up density.

    One last detail I have not mentioned is that when you reduce developing times, you also reduce film sensitivity a little bit. Not much, but a little bit. If you want a more precise calibration, just change one variable at a time instead of changing the two as I said in my example, and control for the constancy of the other between tests. For example, reduce development time first, and see whether your first grey falls at the same place. If it it does, you're set. If it does not, adjust your EI in consequence.
    Using film since before it was hip.


    "One of the most singular characters of the hyposulphites, is the property their solutions possess of dissolving muriate of silver and retaining it in considerable quantity in permanent solution" — Sir John Frederick William Herschel, "On the Hyposulphurous Acid and its Compounds." The Edinburgh Philosophical Journal, Vol. 1 (8 Jan. 1819): 8-29. p. 11

    My APUG Portfolio

  8. #18
    timbo10ca's Avatar
    Join Date
    Apr 2006
    Location
    Winnipeg, MB Canada
    Shooter
    Multi Format
    Posts
    543
    Images
    39
    Quote Originally Posted by Roger Hicks View Post
    Dear Tim,

    It's ALL subjective, too. The science of exposure is nothing like as exact as most people assume, and there's a lot of latitude you can fix in the darkroom.

    'First grey' is easy: if you can see it at a hard/discontinuous junction (neg density = 0.03 or above), you've got it. Going as high as 0.10 or even 0.15 will do no harm.

    Not sure what you mean by 'minimum black'. Presumably the minimum exposure required to get the maximum black of which the paper is capable. If it is that, it ain't difficult either.

    This won't alter the way you want to work, so in that sense it's useless, but you might care to look at 'Why we don't use the Zone System' in the Photo School at www.rogerandfrances.com, just for an additional perspective. It's free, so all it costs you as a couple of minutes of your time.

    Cheers,

    R.
    Thanks Roger- I think your site is a wealth of useful information. Maybe I'm getting overly neurotic about the whole thing because I think my negs look like crap, while so many other people are getting great ones, and hammering home the importance of getting pristine negs to print. BTW- that's exactly what I meant by minimum black,

    Tim
    If only we could pull out our brains and use only our eyes. P. Picasso

    http://www.timbowlesphotography.com

  9. #19

    Join Date
    May 2004
    Location
    Florida
    Shooter
    Pinhole
    Posts
    141
    Images
    7
    +1 for the Picker book recommendation. He did a good job of distilling the ZS down to the bare essentials without making a religion out of it. The book offers straightforward tests for determining your "personal" film speed and developing time. A film with a box speed of 400 may need to be rated higher or lower depending on how the shutter in your camera is firing. No two cameras are alike. Don't scrimp on the testing and assume what works in one of your cameras will work in another.

  10. #20

    Join Date
    May 2006
    Location
    Northern Aquitaine
    Shooter
    35mm RF
    Posts
    4,913
    Quote Originally Posted by timbo10ca View Post
    Maybe I'm getting overly neurotic about the whole thing because I think my negs look like crap, while so many other people are getting great ones, and hammering home the importance of getting pristine negs to print. BTW- that's exactly what I meant by minimum black,

    Tim
    Dear Tim,

    The REALLY easy approach:

    Bracket all your next roll, +/- 1 stop. Print the ones you like best(usually +1!)

    If they print best on grade 2 to 3, your dev times are spot on. If you need 1 to 2 (or 0), decrease your dev time by 20%. If you need 3 to 4 (or 5), increase it by 10%.

    Zero in from there on what you like best. If there's plenty of shadow detail, go up 1/3 to 2/3 stop. If they print on 2-3-4,cut dev another 5%. If they print on 1-2-3, increase it 10%. Your aim is a speed that gives you the shadow detail you want, plus a full tonal range on grade 2 or 3.

    Your personal best negs might be +2/3 stop at the manufacturers' dev times, or manufacturer's ISO speed +10%, on the dev times, or something else. A lot depends on how you meter, too. With a spot meter, I use ISO box speed or box speed +1/3 (eg ISO 400>EI320). With an in-camera meter, I use anything from around box speed (overcast) to half box speed (sunny) -- though developers can influence true ISO speed from 2/3 stop faster (ISO 400>ISO 650) to a stop or more slower (ISO 400> ISO 200).

    Always compare prints, Is A better than B? Go for the EI/dev time that gave you A. Reduce both EI variations (less than 1/3 stop is meaningless) and dev variations (under +10/-5% is meaningless) until you're happy.

    Cheers,

    R.

Page 2 of 29 FirstFirst 1234567812 ... LastLast


 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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