Paper Maximum Density?

Discussion in 'B&W: Film, Paper, Chemistry' started by PhilipRingler, Feb 10, 2008.

  1. PhilipRingler

    PhilipRingler Member

    Messages:
    79
    Joined:
    Dec 11, 2007
    Location:
    Oakland, CA
    Shooter:
    35mm
    Hello,
    Does photographic paper "Maximum Density" refer to the deepest black that can be achieved in the print? If so, I am a bit confused about how the numbers work.
    Is 1.6 a satisfactory maximum density for reaching real blacks? For example, Kentmere Art Classic technical data sheet says that the max density is 1.6, but in reference to what? And what does that really mean?
    :confused:
     
  2. keithwms

    keithwms Member

    Messages:
    6,070
    Joined:
    Oct 14, 2006
    Location:
    Charlottesvi
    Shooter:
    Multi Format
    It's a log base 10 scale; -log(Ireflected/I_incident) if I remember correctly. In which I define

    I_reflected=I_r = light reflected
    I_incident-I=light incident

    So in other words Dmax 2 means -log(I_r/I)=2 so I_r/I=10^(-2) and 1/100 or 1% of the incident light is being reflected. If I did my math right, you'd better check it!

    Obviously deeper Dmax means less light is reflected and the deeper the black. But Dmin is also a consideration, and the overall feeling of tonality has to do with how much ueful range lies between the two... and whether the reflection is truly neutral and black as opposed to some metamerized thing like you still get with some inkjet prints.

    For reference, note that log(2) is ~0.3. So you can divide Dmax-Dmin by 0.3 and get a rough idea of the range in stops.

    If I got my definition wrong, somebody will set it straight!

    Anyway, the big point is that on rougher textured papers you will not see a high DMax. That doesn't mean that the blacks suck, it means that they are reflecting the light in a different way than glossy papers. Of course sometimes textured paper makes a print look better, sometimes it doesn't, that's up to you to decide. But generally if you want really deep blacks well distinguished from bright whites then you are looking for a smoother paper texture.
     
  3. Ole

    Ole Moderator Staff Member Moderator

    Messages:
    9,281
    Joined:
    Sep 9, 2002
    Location:
    Bergen, Norw
    Shooter:
    Large Format
    Some glossy papers reach Dmax as high as 2.3, some non-glossy papers only reach 1.6.

    Yet the most convincing total black I've ever seen is from Bergger Art Classic Silver Supreme, which has been measured to only 1.6. Sometimes better numbers don't necessarily mean better blacks.
     
  4. dancqu

    dancqu Member

    Messages:
    3,676
    Joined:
    Sep 7, 2002
    Location:
    Willamette V
    Shooter:
    Medium Format
    Why the ~ and not an = ? Dan
     
  5. keithwms

    keithwms Member

    Messages:
    6,070
    Joined:
    Oct 14, 2006
    Location:
    Charlottesvi
    Shooter:
    Multi Format
    Well, according to google,

    log(2)=0.301029996

    And google must be right, you know.

    Let's see, google also says

    pi=3.14159265

    and that's pretty close :wink:
     
  6. cao

    cao Member

    Messages:
    188
    Joined:
    Oct 5, 2004
    Shooter:
    35mm
    Because 2 raised to 10 does not equal 10 raised to 3.

    Algebra left as an exercise for the reader.
     
  7. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,908
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    Just FYI, the laws of physics prevent reflection print materials from achieving densities much above 2.2 due to internal reflections. By playing tricks with incorporated materials designed to overcome this, you can get as high as 3.0, but the result is fleeting as the paper emulsion absorbs moisture and changes texture.

    Density also varies with surface, glossy paper being higher than matte paper.

    PE
     
  8. jgjbowen

    jgjbowen Member

    Messages:
    879
    Joined:
    Oct 13, 2003
    Location:
    Richmond, VA
    Shooter:
    Large Format
    I've been rereading the old Zone VI newsletters. In them Fred mentions that Oriental Seagull had a dmax of 2.05 and that Brillilant (circa 1985)had a dmax of 2.15.
     
    Last edited by a moderator: Feb 10, 2008