Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,495   Posts: 1,543,020   Online: 759
      
Page 4 of 10 FirstFirst 12345678910 LastLast
Results 31 to 40 of 95
  1. #31

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,719
    Just don't get too carried away with it, Stone. Often people plot curves and think they know what they are going to get but drawing meaningful conclusions from the data can actually be tricky. There are different ways of testing, and many variables, including differences between testing conditions and shooting conditions.

    You might want to get yourself a copy of Ansel Adams's The Negative. There is an easy to understand primer on densitometry and characteristic curves in the book.

    Incidentally, to anyone who owns a copy of Haist, the end of the first book has a pretty good chapter on sensitometry/densitometry, curves etc. Just mentioning it because while Haist is a common reference for photochemistry, there's other excellent stuff in there too.

  2. #32
    StoneNYC's Avatar
    Join Date
    Aug 2012
    Location
    Connecticut, USA
    Shooter
    8x10 Format
    Posts
    7,312
    Images
    225

    T-Max 400 has boomerang curve

    Quote Originally Posted by Michael R 1974 View Post
    Just don't get too carried away with it, Stone. Often people plot curves and think they know what they are going to get but drawing meaningful conclusions from the data can actually be tricky. There are different ways of testing, and many variables, including differences between testing conditions and shooting conditions.

    You might want to get yourself a copy of Ansel Adams's The Negative. There is an easy to understand primer on densitometry and characteristic curves in the book.

    Incidentally, to anyone who owns a copy of Haist, the end of the first book has a pretty good chapter on sensitometry/densitometry, curves etc. Just mentioning it because while Haist is a common reference for photochemistry, there's other excellent stuff in there too.
    Thanks.


    ~Stone

    Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk
    ~Stone | "...of course, that's just my opinion. I could be wrong." ~Dennis Miller

  3. #33

    Join Date
    Jul 2011
    Shooter
    8x10 Format
    Posts
    2,601
    The most important thing is to plot different film/chem curves all in the same manner, so that comparisons will be meaningful. It also helps to show multiple curves with different development times.
    I also try to plot the same kind of log spacing characteristic of published mfg curves (on the tech sheets), so that it is intuitive to read these as well. It tells you a great deal at a glance if you know
    what to look for.

  4. #34

    Join Date
    Apr 2008
    Location
    Escondido, California, USA
    Shooter
    35mm RF
    Posts
    655
    This morning, Michael R posted his curves of TMY-2 (same batch as mine) here:
    http://www.apug.org/forums/forum37/1...ntrate-51.html

    He got the same boomerang shape, with the inflection in about the same place. So that shape is really there, and was not my mistake. But as another poster pointed out, I hope the slope-change is small enough that most people won't be bothered by it.

    Mark Overton

  5. #35

    Join Date
    Feb 2010
    Location
    Montreal, Canada
    Shooter
    Multi Format
    Posts
    4,719
    Hi Mark - sorry I just realized I had posted the curves in the wrong thread. Thanks for moving it over here. After I ran the test with D-76 I thought it would be a good idea to try it again with DDX, if for no other reason than DDX is probably the most consistent developer I've ever used, and also gives fairly straight curves with TMX100, Delta 100 etc. So I figured more data is usually better.

    It is indeed a strange shape for TMAX, but not one that would bother me too much as a user.

  6. #36
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,005
    Images
    65
    Try bringing this to the attention of the guys at EK.

    PE

  7. #37
    EASmithV's Avatar
    Join Date
    Aug 2008
    Location
    Maryland
    Shooter
    Multi Format
    Posts
    1,874
    Blog Entries
    4
    Images
    122
    Quote Originally Posted by noacronym View Post
    I never liked Kodak dropping the Plus-X, Verichrome Pan, and Tri-X for this T-max stuff. Never liked it. If it's not broke, don't fix it.
    I agree. I hate the way T-max looks in all but perfect or controlled lighting.
    www.EASmithV.com

    "The camera is an instrument that teaches people how to see without a camera."— Dorothea Lange
    http://www.flickr.com/easmithv/
    RIP Kodachrome

  8. #38
    StoneNYC's Avatar
    Join Date
    Aug 2012
    Location
    Connecticut, USA
    Shooter
    8x10 Format
    Posts
    7,312
    Images
    225

    T-Max 400 has boomerang curve

    Quote Originally Posted by EASmithV View Post
    I agree. I hate the way T-max looks in all but perfect or controlled lighting.
    I've found if you rate Tmax400 at EI320 and develop in Rodinal 1:50 at 1/2 stop longer standard dev time (about 1 to 1.5 minutes longer) you can get more pleasing results to what you and I like

    Try it. Oh and you need to only gently agitate 1 inversion per minute instead of a bunch and VERY gently and that seems to help a LOT


    ~Stone

    Mamiya: 7 II, RZ67 Pro II / Canon: 1V, AE-1, 5DmkII / Kodak: No 1 Pocket Autographic, No 1A Pocket Autographic | Sent w/ iPhone using Tapatalk
    ~Stone | "...of course, that's just my opinion. I could be wrong." ~Dennis Miller

  9. #39
    c6h6o3's Avatar
    Join Date
    Oct 2002
    Shooter
    Large Format
    Posts
    3,179
    Images
    6
    Curves shmurves. 400TMax has the longest, straightest response curve of any film I've ever used. Take a look at this photograph, shot on 8x10 400TMax sheet film. There are approximately 12 zones between the shadows in the vaults and the highlights in the rosette. The proof of the pudding is in the tasting.

    Having said that, I should also point out that I've heard that there's a difference between the TMax roll film and the sheet film; namely, that there's a dye in the roll film that blocks UV. I don't know if that is true or not. Maybe Ron knows. If true, it might account for your results differing so drastically from my experience.
    Jim

  10. #40

    Join Date
    Apr 2008
    Location
    Escondido, California, USA
    Shooter
    35mm RF
    Posts
    655
    Quote Originally Posted by noacronym View Post
    Your link seems to require the reader have a facebook account. As for me; no thank you.Wish you'd have just posted an attachment here.
    I downloaded Jim's pic. With his permission, I'll post it to this thread.
    It's a stunning shot of the interior of a cathedral consisting mostly of shadows and midtones, with solid white highlights in the stained glass.

    Mark Overton



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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