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  1. #1

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    Durst Micro T analyzer anyone ?!

    As I just started printing RA4, I thought of taking this analyzer out of storage and having a closer look. I am completely confused (of course I have no manual). Part of the confusion surely comes from my lack of understanding/vocabulary/etc as regards color printing. Some confusion must also derive from the crazy apparant complication that's in this 5x8 inch machine. It became quickly clear that some features only light up when 2 or more buttons are pressed simultaneously. I suspect this is a full featured color analyzer and enlarging timer. I just want to program it for neutral and density, and get on with it! Any help will be greately appreciated...
    Attached Thumbnails Attached Thumbnails microt.jpg  

  2. #2
    Mike Wilde's Avatar
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    Luigi: I sent you an email with a zip of the docs I have for my analyser - not the same as yours, but to get your brain primed to figure out yours.

    Do you have any reference negatives? a measuring probe, or a test print analyser (made by Durst also)? In the last part of my post there is a snip of the TPA function from briank.co.uk's site.

    The basic operation is to select a mode, analyse a reference you hope to emulate in the new print, print a test print, and analyse the result against the reference colour that the analyser has electronically stored.

    The reference does not always have to be just one thing. That is what seelcting different channnels does. I run a colorstar 3000 analyser, and it has 8 channles; later ones had 100.

    I suspect you put it in b&w and only the exp time would light up.
    (stick with b&w for now to simplify learning it's function with with just density to deal with)

    Function would cycle you though the list of LED's down the left of the machine.
    Mode would select B&W, neg or pos. Neg is c-41 printing RA-4, and pos is E6 or Kodachrome printing onto reversal paper (ie Cibachrome)

    Master is usually a global adjustment applied to all channels. It is used to adjust for aging paper, different paper batches or shifting aging chemistry. Figure out what the range of valuse are for it and set it mid range to start, until you know better how the process reacts.

    Ref Mode is likely used to bring up the reference value for the channel. You might press ref value multiple times to bring each of y/m/c active - and tune the numeric value using - and + to whatever value is supplied with the reference neg or grey card chip. Alternatively you might zero the three readings all at once to zero.

    Then you would make a print with the test neg, and see what you get.

    X comp - not sure

    Film offset - might be like master, allowing you to adjust for different film base colours and ally the setting to all channels

    Integral - where you have a scene with no good grey or grey analog like white or black to set the color balance, and then adjust the exposure. Put a diffusion under the lens when metering. In theory all colors integrate to grey.

    Multipoint. Lets you make muliple probe readings, and the analyser then averages them for an exposure time. Usally you press a button to signal each point taken. Might be a button on the probe, or one of the keys on the analyser.

    Hope this is enough to get you started.

    Test Print Analyser
    The electronic enlarger head for the M70 has provision for a Test Print Analyser (TPA).


    Durst Micro Test Print Analyser (TPA)

    The TPA is very useful for calibrating and correcting casts when making colour prints. It allows light reflected from a small test print made from a negative of a standard 18% gray card to be compared against light reflected from a reference card. The filter controls can then be adjusted to correct for any colour cast once the exposure has been calibrated for the correct density.

    The TPA slots into the enlarger in place of the negative carrier. The print sample and reference card are inserted into a slide. The colour analyser probe fits into a slot in the TPA and receives light from the enlarger head reflected from the surface of the sample via a mirror. The electronic head displays the difference both in density and colour (Cyan, Yellow, Magenta) between the sample and the reference. The exposure and filter controls are then adjusted until the display indicates zero. The process may need to be repeated 3 or 4 times to achieve the correct density neutral gray print but it's still easier than trying to assess a colour cast by eye.

    The human eye is good at detecting colour casts but it is not good at identifying what the cast is. For example, I find it difficult to tell the difference between a slight magenta cast and a red cast or between a slight cyan cast and a blue cast. The ambient lighting used to view the print makes a big difference as does the background. Attempting to make adjustments to the colour balance at night using ordinary domestic tungsten lighting is hopeless. The TPA overcomes these problems - at least to some extent. You can only calibrate the filtration and remove the colour cast for a particular print density. With the RA-4 paper I normally use, I find that if you adjust the filtration for a neutral gray print from an image of an 18% gray card, then lighter areas may have a slight magenta cast while darker areas may have a green cast. This is down to the film and paper characteristics. With darkroom printing there is not much you can do to overcome this problem. The effect only slight and it's not normally noticeable with most images that have a mix of dark and light tones. With digital printing you can apply correction curves over the entire tonal range.
    my real name, imagine that.

  3. #3

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    Thanks Mike. Things are coming together.... I have the probe, but no test negatives. I'll continue my research



 

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