Ilford MG 500H Probe Readings

Discussion in 'Enlarging' started by Katie, Feb 1, 2012.

  1. Katie

    Katie Subscriber

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    So all along I thought my probe was nuts. No matter where I put it on the neg - it was never right. I thought it was maybe the 50mm lens for my 35mm negs (vs. my 80mm lens for MF or my 135mm lens for using my nifty new contact enlargement thingy ma bob).

    So today - I was printing some proofs for a friend and was using RC paper instead of my usual fiber paper (all Ilford) and voila! the probe was DEAD ON with three different negs (two HP5 and one TRI-X).

    So is my probe set up for RC paper printing times or what?

    I print both, so don't mind it working for RC, but is there a formula I can use to get it correct (like 2.5X factor, which was kinda ballparking it for me before with FB) with both?
     
  2. L Gebhardt

    L Gebhardt Subscriber

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    Katie, I forget if you have the instructions for the probe. If you don't, I can scan them in.

    But you should be able to easily calibrate it for either paper. The manual I have says it was calibrated for Multigrade II paper, but doesn't say FB or RC. You are supposed to measure a shadow area which you want to retain detail, according to the manual. To calibrate you basically make a print that looks good and note the time. Then place the probe in a shadow area (bright part of the image). Then take a reading and adjust the dial until the taken reading matches your known good time. They warn that the probe may need to be calibrated for each batch of paper. My experience with other enlarging meters says this isn't usually the case with Ilford papers, but between papers there is quite a variation.
     
  3. Katie

    Katie Subscriber

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    So I would need to recalibrating for each paper? Guess I should stick to one then. I did not realize that fiber and rc would be so different. We are talking about expired paper here, too...
     
  4. L Gebhardt

    L Gebhardt Subscriber

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    I would think you could just make note of the setting for each paper. Should be easy enough to see if it returns to the same value each time you turn the wheel to a particular number. Then you could use say 2 for RC and 5 for FB (made up numbers).
     
  5. ParkerSmithPhoto

    ParkerSmithPhoto Subscriber

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    I finally got my 500H set up and started working with it tonight. Plugged in the probe, took a reading and the controller spelled out "HELP." Promptly unplugged and made a test strip.

    Kind of weird with the blue and green lights, isn't it? Prints look real purdy, though. :D
     
  6. Andrew4x5

    Andrew4x5 Member

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    I've attached a copy of the instructions for the probe.
    I haven't used the probe for a while because I bought an Analyser Pro 500 (which replaces both the probe and control unit - highly recommended).
    From memory, you measure an area of dark shadow (about Zone 1). You then make a print in which the measured area has the correct density, and then follow the instructions to calibrate the probe.

    If you use several papers, you can use the Calibration knob to switch between papers - for example, Ilford may be setting 5, and Kodak setting 7.


    Regarding the "HELP" message, the number indicates the fault:
    2 Calibration knob between two numbers.
    3 (or 5) Too much light to measure - stop down lens.
    4 Not enough light to measure - open up lens.

    To cancel the help message, press the Expose/Cancel button on the control unit.




    ProbeInstructions.jpg
     
  7. ParkerSmithPhoto

    ParkerSmithPhoto Subscriber

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    Thanks for posting that.

    We used to use these in a commercial lab back in the late 90s. I didn't remember them using the green light for focusing. It's surprising how dim it is.

    Do you have the blue green setup?
     
  8. Andrew4x5

    Andrew4x5 Member

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    I had assumed that both lights were on during focusing/exposure measurement, but the colour was definitely on the green side - from memory, it was about grade 1. (Personally, I would call the colour yellow-green, rather than green.)

    I'm surprised that you find the green light dim because, to the eye, it's far, far brighter than the blue light. The relative green/blue brightness is very obvious with the the Analyser Pro 500 because, during exposure, the lamps are turned on sequentially - so, while the image might be quite bright during the green exposure, it's almost invisible during the blue exposure.
     
  9. ParkerSmithPhoto

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    It was a lot easier tonight. My print was at a Grade 5, so the focusing light definitely looked a lot brighter compared to that! Still seems a bit dim when focusing, but nothing I can't get used to. Wether this will replace the LPL still to be determined. I do miss using my f-stop timer.
     
  10. ic-racer

    ic-racer Member

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    If you don't think the lights are not the same brightness, make sure the "Program" switch is set correctly on the back of the controller.
     
  11. Andrew4x5

    Andrew4x5 Member

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    From memory, the focusing light is always the same regardless of the grade you select; it's only during exposure that you see the changes in colour between grades. If the focusing (green) lamp seems dim, the wrong bulb might be fitted, such as 150W for green and 300W for blue.

    Although the program switch does change the intensity of the green light, the changes are small - in the order of 10% per step. The program switch is used to balance the relative intensities of the lamps so that when you select a grade, the lamps correctly expose for that grade.