Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,202   Posts: 1,531,585   Online: 1131
      
Results 1 to 6 of 6
  1. #1
    Silverpixels5's Avatar
    Join Date
    Mar 2003
    Location
    Houston, TX
    Shooter
    Multi Format
    Posts
    594
    Images
    15
    I did a speed test on APX 100 in Rodinal 1:50, then took the film to the local lab to get denisity readings for each shot. I was in a rush to get back here to work so I didn't have time to ask him about the numbers. The readings are whole numbers, and I would think I would just have to take the base 10 log of each, and subtract out the FB+fog, to get the density, but it seems like my numbers are a bit high. Here's the numbers I got from the lab:

    Zone 1: 18
    Zone 0.5: 14
    Zone 1.5 : 22
    Zone 2: 27
    Zone 8: 99
    Zone 7.5: 89
    Zone 8.5 : 108
    Zone 9: 130
    Zone 0: 9

    Any help in this would be greatly appreciated. Thanks!

  2. #2

    Join Date
    Sep 2002
    Location
    France
    Shooter
    Multi Format
    Posts
    357
    You must divide the numbers by 100 to get logD readings. The zone 0 reading states film base and fog density. If this reading is omitted, the FB+fog is usually already subtracted.

  3. #3
    Silverpixels5's Avatar
    Join Date
    Mar 2003
    Location
    Houston, TX
    Shooter
    Multi Format
    Posts
    594
    Images
    15
    Thanks! Everything works out great now, plus I feel pretty stupid. I'll put this college degree to use one of these days...lol....
    RL Foley

  4. #4
    Silverpixels5's Avatar
    Join Date
    Mar 2003
    Location
    Houston, TX
    Shooter
    Multi Format
    Posts
    594
    Images
    15
    Ok if i'm interpreting this correctly then my film speed of 100 is about right with a Zone 1 density of 0.09, but my Zone VIII exposure is too low with a reading of 0.9. So this means I need to increase my development time in order to get my Zone VIII exposure to about a 1.3, correct?
    RL Foley

  5. #5

    Join Date
    Sep 2002
    Location
    France
    Shooter
    Multi Format
    Posts
    357
    Quote Originally Posted by Silverpixels5
    So this means I need to increase my development time in order to get my Zone VIII exposure to about a 1.3, correct?
    That's correct. Whether 1.3logD is good for Zone VIII depends on your enlarger head. The densitometer readings are taken with a diffuse light source. If you use a condensor head, 1.1-1.2 logD would be more apropriate for a Zone VIII.

  6. #6
    Silverpixels5's Avatar
    Join Date
    Mar 2003
    Location
    Houston, TX
    Shooter
    Multi Format
    Posts
    594
    Images
    15
    Thanks for that bit of info, because I do use a condenser head!
    RL Foley



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



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