condenser/difusion enlarger question

Discussion in 'Darkroom Developing and Printing' started by 10x, Nov 3, 2003.

  1. 10x

    10x Guest

    If film is developed to a density to suit a difusion enlarger, how
    does this affect the contrast when the film is used to make prints
    with a condensor enlarger.

    I'm just setting up a darkroom again after a twenty five year break.
     
    10x, Nov 3, 2003
    #1
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  2. 10x

    Frank Pittel Guest

    wrote:
    : If film is developed to a density to suit a difusion enlarger, how
    : does this affect the contrast when the film is used to make prints
    : with a condensor enlarger.

    The negative will print with higher contrast.

    : I'm just setting up a darkroom again after a twenty five year break.

    Welcome back. I hope you stay!
    --




    Keep working millions on welfare depend on you
     
    Frank Pittel, Nov 3, 2003
    #2
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  3. Research published a couple years ago in Photo Techniques USA concluded
    that there is no measurable difference in contrast when printing with a
    diffusion head or a condensor head.


    Francis A. Miniter
     
    Francis A. Miniter, Nov 3, 2003
    #3
  4. 10x

    Mark A Guest

    That is totally bogus or a misinterpretation of what they said.

    What some people say is that the diffusion enlarger produces less contrast
    (it comes very close to a contact print in contrast) than a condenser
    enlarger, but the difference can be adjusted for during film development
    (which affects negative contract) or adjusted by using a different grade of
    paper.
     
    Mark A, Nov 3, 2003
    #4
  5. 10x

    Jim Phelps Guest

    Mark,

    There's enough empirical and scientific evidence out there to disprove
    this myth. There is only a very slight visual difference between the two
    (condenser head and diffusion head). There is an appreciable visual
    difference with a cold light source, but that is chiefly due to the spectrum
    of the light output. I believe (and from my own experience) there's about
    (but not quite) 1/2 paper grade difference. Depends upon the paper.

    I think the reason is the majority of diffusion heads don't really
    diffuse the light enough. For it to be a true diffusion source, the light
    has to come from all angels of direction within the hemisphere above the
    negative. Cold light sources come close, but frosted glass (plastic)
    diffusers do not.

    Jim
     
    Jim Phelps, Nov 3, 2003
    #5
  6. 10x

    Mark A Guest

    Research published a couple years ago in Photo Techniques USA
    concluded
    The words used by Francis were "no measurable difference."

    "No measurable difference" means none, zero, etc. It does not mean "very
    slight visual difference." In fact, I would think that not all measurable
    differences would be visible.

    But your point about the variability of enlarger light sources is a good
    one. Cold Lights typically are more diffuse than color heads, and not all
    condenser enlargers are equal in their commingling characteristics.

    Not even all cold lights are the same, even from the same light source
    manufacturer, because the enlarger design does not allow the cold lights to
    be placed the exact same distance from the negative on all models of
    enlargers.
     
    Mark A, Nov 3, 2003
    #6
  7. No difference at all? Well, don't know about that, but even a slight
    difference can be corrected using a different grade paper or filter.
    Point is that you can get identical prints (in all practical terms) from
    both systems from one negative. And guess what, both types are very
    suitable for 35mm enlarging as well as larger negative enlarging as
    opposed to what some people might say...

    Severi
     
    Severi Salminen, Nov 3, 2003
    #7
  8. 10x

    Jorge Omar Guest

    You will need one paper grade less typically. Next time, develop some 20%
    less.

    Jorge

    wrote in 4ax.com:
     
    Jorge Omar, Nov 3, 2003
    #8
  9. Most enlargers with condensors (Beseler and Omega, for example) are only
    quasi-condensor since they use a diffuse large light source.
    True condensor light sources using a point light have been made but are
    usually used for enlarging electron microscope images and the like.
    The problem with this type is the exaggeration of the defects in the
    film and the more obvious grain.
    So my guess is that you will see less than 1 grade difference in
    contrast. I would recommend developing and exposing to ensure good
    shadow detail. Then if you have contrast problems use a lower grade of
    paper.
     
    Robert D Feinman, Nov 3, 2003
    #9
  10. 10x

    jjs Guest

    (condenser vs diffusion)

    If there is no significant difference then why did Leitz, in their
    infinite wisdom, ever commit exclusively to a condenser enlarger?

    Why does _anyone_ use a condenser enlarger when it seems the only
    _significant_ difference is that the condenser enlarger prints profound,
    sharp DUST?

    If the dust is so sharp and contrasty, why isn't the negative sharper and
    more contrasty?
     
    jjs, Nov 3, 2003
    #10
  11. 10x

    Jorge Omar Guest

    If you have an enlarger with a true point source, prints WILL be more
    contrasty and (I believe) sharper - but will show ALL blemishes. Light
    point sources are almost the norm for Minox prints.

    So I think manufacturers looked for a midpoint. And diffusion enlargers
    were not usual before color printing become popular.

    Jorge

    (jjs) wrote in
     
    Jorge Omar, Nov 3, 2003
    #11
  12. Anchell and Troop for their book, "The Film Developing Cookbook", lsuggest a
    half grade or less difference...

    Ctein, in his book, "Post Exposure , etc." states that after doing hundreds
    of prints with careful matching of density and contrast range, that there is
    no measurable difference between diffusion and condensor prints...
    Get an enlarger and have at it... Welcome back...
    Denny
     
    Dennis O'Connor, Nov 3, 2003
    #12
  13. And my condensor enlarger/lens may be a half grade to a whole grade
    different from your condensor enlarger/lens combination... I have both
    types and I can see no difference between them...
    Denny
     
    Dennis O'Connor, Nov 3, 2003
    #13
  14. There is about a 1/2 to 1 grade difference in contrast with most
    coneventional films favoring the condenser (meaning the condenser
    provides more contrast) depending on the design of the enlargers being
    compared. You should develop the film less for a condenser by about
    15-25% compared to a diffusion enlarger. You'll have to experiment a
    little depending on the results you get until you arrive at the
    optimum. Some people prefer a diffusion enlarger, some prefer a
    condenser. I prefer the condenser type because it allows less
    development of the film and thus sharper images with less grain.
     
    Michael Scarpitti, Nov 3, 2003
    #14
  15. 10x

    Mark A Guest

    Ctein, in his book, "Post Exposure , etc." states that after doing
    hundreds
    Again, you are misinterpreting what Ctein and others are saying. They mean
    that AFTER you adjust for contrast (either by negative development or paper
    contrast grade) there is no difference. They are NOT saying that there is no
    contrast difference between condenser and diffusion for the same negative
    and the same paper (with same VC filter if applicable).
     
    Mark A, Nov 3, 2003
    #15
  16. 10x

    Jim Phelps Guest

    OK, let's make a real discussion out of this.

    Could it be, as Robert Feinman put it so well in his post, the point
    source of light is too large in the average enlarger to be of serious
    consequence in condenser mode? Could it also be as I put in my post that
    the diffusers are slightly inefficient? Let's look at both of these.

    First, the large diameter of the light source in both frosted bulb and
    Quartz Halogen light sources are pretty much the same size. Why? Most QH
    sources have some form of diffuser to mix the light, usually after it passes
    through the Dichroic filters. It has to to mix the filter colors. This
    should result in a light source approximately the same size as the PH-222
    bulb (for the sake of argument). This light is passed through a set of
    condenser elements consisting of [usually] two Plano-Convex surfaces. The
    focus of this lens set is adjusted for the format of the negative and the
    light source. This rather large source of light above the lens element
    would then have a rather reduced Callier effect as some of the light is
    coming from less than optimal angels (there is not definitive point source
    of light, but rather a large area source). Also, because of the fixed size
    of the light source, the focae of both sides of the lens element do not
    occur at the same distance if the size of one of them is variable (as in
    Beseler heads among others). Due to this out of focus light entering the
    condensers, and the fact that most of the light entering the condenser set
    is somewhat diffused to begin with, the Callier effect will be reduced,
    lowering overall contrast.

    Now, most diffusion sources (let's leave out cold light sources as they
    have a different effect on contrast as well due to their output spectrum)
    are the same light source as used above, but with several layers of opal
    glass (whether glass or plastic is irrelevant) to diffuse the light. This
    diffused source sits some short distance from the negative stage and
    provides light waves coming from many, but not all angels in the hemisphere
    above the negative stage. It's about 85% from perfect diffusion (some
    angels of light are denied due to the thickness of the negative carrier).

    OK, now I've used the same negative in my Beseler 23C-II with a Dual
    Dichro colorhead, and leaving the filters and the negative at the same spot,
    I have printed the negative twice onto the same paper after changing over
    from Condenser to Diffusion between prints. I used my Jobo Analyzer to
    determine exposure on the same area of the negative as there would be
    different light levels between the heads. Just to make all thing equal, I
    processed them together. In the end, my Jobo ColorLine 7000 shows only
    about a 1/2 grade difference between prints. I used the Jobo in contrast
    determination mode and analyzed the same two areas on both prints (I
    selected several negatives with favorable characteristics to do this) I
    found this to be true using both PXP (old stock) and TP films. The PXP was
    developed in D-76 and the TP in Technidol. It really doesn't matter if I
    developed them to 10, 20, 30 or even 40% more/less than the recommended
    times. I can tell you that I normally develop PXP in D-76 for 5:15 at 20
    and TP for 8:30 at 20. I've only recently changed over from D-76 and
    occasionlly HC-110B for PXP to PMK, but I did not use those negatives.
    These times are not far off from the recommended times. Oh yeah, if it
    matters, I have a Rodenstock APO-Rodagon 80/4 lens on the enlarger. Camera
    was a Rollei 6008i with a Rollei/Zeiss 80/2.8 PQS lens with HFT coating
    (Same as *T).

    Now, what does this prove? My methods do not show an enormous amount of
    difference between diffusion or condenser enlargements. Here's the
    disclaimer: This experiment shows how my equipment and methods respond. My
    methods work for me, and unless you do everything the same way and own the
    same exact equipment (hell, use my darkroom) I do, your results may be
    different.

    Back to the discussion. Could the myth of the Condenser/Diffusion
    enlarger be untrue? I believe it's not as big of a difference as we have
    been lead to believe. About the difference in looking at a print on Glossy
    as opposed to Matte surfaces. I do know, I use my enlarger in Diffusion
    mode for certain effects. One of which is to diminish the effects of
    scratches on a negative. Edwals No Scratch can only do so much.

    Any other thoughts? And please, let's keep it civilized. Been to much
    horse hockey (no, not polo) lately.

    Jim,
    Trying to lead an educational and adult discussion.
     
    Jim Phelps, Nov 3, 2003
    #16
  17. 10x

    Jorge Omar Guest

    Ok, I may be wrong in that one. Honestly, I've never used an diffusion
    enlarger, just semi-diffused condensers. Just saw that value (1 grade)
    somewhere.

    Jorge
     
    Jorge Omar, Nov 3, 2003
    #17
  18. Your prints (using the same paper grade as was used to print with a
    diffusion enlarger) will have lighter print values than expected above
    middle grey. The mid-tones to low values should remain virtually the
    same. Depending on the enlarger, the contrast difference is equivalent
    to 1/2 to a full paper grade. So, to compensate, use the next lower
    paper grade or, for more control, a two bath developer or a combination
    of both.
     
    Stefan Patric, Nov 3, 2003
    #18
  19. To clarify: film needs to be developed for one or the other. You could
    'split the difference', I guess, if you want to use both, but it's
    better to decide which you're going to use and adjust your times based
    on that choice.
     
    Michael Scarpitti, Nov 3, 2003
    #19
  20. 10x

    Dan Quinn Guest

    RE: wrote
    Search this NG for, magenta effect . It will only effect
    VC papers. Dan
     
    Dan Quinn, Nov 3, 2003
    #20
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