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  1. #1

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    Meopta colour 3 filter grades.

    Hi, I have recently bought a Meopta Magnifax 4a with the Color 3 head which I will use for B&W printing, mainly with Ilford RC papers. In the Ilford multigrade paper instructions, there is a table which gives the dial up filtration on the Meopta, needed for each grade. Will this keep the same exposure level for all grades or will significant compensation be needed?
    I am using a Durst color enlarger at the moment, its combination filtration seems to keep the exposure constant, but the table for the Meopta gives only the single filter level. I have not got it ready to use just yet, I thought that I might get ahead by asking for your experience here.
    Dave...

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    Dave, my modus operandi with Magnifax4 (older model) and Colour 3 head is that, when I establish contrast, I make my test strips using M and Y for that contrast grade, and use time established with that filtering. I know people first establish exposure time, and after that contrast, but I do vice versa. In theory, if you use only one filter for contrast (only M or only Y), then you use same time for contrast 00 to 3 grade, and double that time for 3,5 to 5 grade. Same theory tells that is you use both filters in same time for contrast, that is if you don't establish contrast, let say 4, with only M, but with combination of M and Y, then you use same exposure time regardless of contrast.

    So, theory say next: You establish exposure time, for example 20 sec, using non graded test strips (that is using not filtered light from enlarger head, that is bacis grade for that paper. Basic grade for variable contrast papers, when exposed using not filtered light, depending of manufacturer, are usually grade 2 or 3. I belive for Ilford MGRC IV basic grade is grade 3). If you use combination of M and Y and make let say five prints with contrast grades respectfuly 1, 2, 3, 4, 5, for every print you will use 20 sec exposure. But if you use let say only Y for grades 1, 2, 3, and only M for 4, 5, then you will use 20 sec exposure time for grades 1, 2, 3, and 40 sec exposure time for grades 4, 5. But, this is theory, best for you is to test and find your way.

    On Meopta's web site, http://www.meopta.cz/index.php?id=121&lang=en there is table for double filtering for newer colour head 4=ES and different papers including Ilford MGIVRC, but I belive fiter values are same as for Colour 3, or use them as starting point.

    Exposure meters/contrast finders like RHdesigns ZoneMaster II or AnalyzerPro or Jobo ComTime, or others like those two, can make life easier.
    Bosnia... You don't have to be crazy to live here, but it helps...
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  3. #3

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    Oh, and there is Meograde head, that is head for variable contrast papers which use only one dial for contrast and preserve same exposure time regardless of contrast grade, so if you like to spend money, all filtering issues will be solved...
    Bosnia... You don't have to be crazy to live here, but it helps...
    No things in life should be left unfinis

  4. #4

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    Thanks Haris,
    I have the handbook for the Color 3 head, it has the table for the conversion of filtration levels to the Kodak and Agfa ranges. This table is identical to the one for the Color 4 head in the link you gave to me. Unfortunately, I couldn't find a table to use to look up Ilford paper grades.
    I seem to remember reading about this somewhere.

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    I just visited Meopta web site before I wrote that link. On bottom of page there is filtration table for Ilford paper, below tables for Kodak and Agfa papers. Those filtration tables are for Meopta Color 4-ES head, not for Color 3, but filters for both heads are I belive the same, 4-ES is newer and have integrated voltage stabilizer, as I knoe that is only difference from Color 3 head. So, for flitration use table on bottom of next page: http://www.meopta.cz/index.php?id=121&lang=en

    I would copy table for you, but I don't know if that would violate copyright of that web site, so, please, look at bottom of page which link I just wrote, there is double filtration table of Ilford paper. I look at that table right now!

    I use that table also, me to use Ilford papers.

    Good luck,
    Bosnia... You don't have to be crazy to live here, but it helps...
    No things in life should be left unfinis

  6. #6

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    Oh, I see!
    I was looking at the PDF files and stuff.
    Sorry!
    This looks nice info. Not quite in agreement with the Ilford paper table for Meopta, but then it doesn't say which Meopta head. I will go and try these settings.
    thanks haris,


    Dave....

  7. #7
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    i know, an old topic, but i'm trying to find info on filtration with the color 3 head.
    it seems the links to the meopta-site don't show what they should.
    any other sources?

    thanks!
    maarten.

  8. #8
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    Ilford have a fact sheet on contrast control for multigrade papers at http://www.ilfordphoto.com/download....8932591755.pdf. It includes suggested filtration for Meopta heads on p. 3 although it does not specify which model head this is for. I use it successfully with my Meochrom II head. Note that the settings in this table don't keep exposure constant across different grades - for example, moving from Grade II (white light) to Grade I (55Y) requires about a one-stop increase in exposure.
    Last edited by andrew.roos; 03-16-2012 at 12:56 PM. Click to view previous post history.

  9. #9
    maarten m's Avatar
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    thanks andrew.

    i already read the "contrast control" sheet from ilford, and the problem was i din't find the exposure compensation guidelines.
    so i went looking all over the web and i think i condensed some interesting information.

    there are 2 ways of gradation control on the meopta color head: one that uses only one color, and another that combines the two.

    if using only one color, these would be the values and according adjustments:

    GR < II (Y = 55(I), 90(0), 150(00)): t=x1.25 (+1/4 stop)
    GR II (Y & M = 0): t (standard setting)
    GR III(M = 40): t x 1.50 (+1/2 stop)
    GR IV(M = 85): t x 2 (+1 stop)
    GR V(M = 200): t x 2.5 (+1 1/2 stop

    also considering the density control takes two stops, and keeping "45" as standard setting,
    which would allow us for 1/2 stop down and 1 1/2 stop up compensation,
    this would give for a constant exposure time (set for GR II):

    GR < II (Y = 55(I), 90(0), 150(00)): D = 37,5
    GR II (Y & M = 0): D = 45
    GR III(M = 40): D = 30
    GR IV(M = 85): D = 15
    GR V(M = 200): D = 00

    if using two color filters to adjust gradation, there would be no need for exposure compensation.
    the values i found for this are:

    GR00: - 105 Y - 00 M
    GR0: - 85 Y - 10 M
    GRI: - 60 Y - 20 M
    GRII: - 40 Y - 45 M
    GRIII: - 20 Y - 60 M
    GRIV: - 10 Y - 75 M
    GR00: - 00 Y - 200 M

    some settings seem to be contradictory (like the settings for grade 00 and 0), but i think it's a good guideline for further testing.

    maarten.

  10. #10
    tih
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    I wouldn't say contradictory. If you subtract the shared filtering
    (the same amount of yellow and magenta won't change contrast; it'll
    just increase exposure time), the Ilford scale becomes:

    Gr Y M Real
    00 105 0 105Y
    0 85 10 75Y
    1 60 20 40Y
    2 40 45 5M
    3 20 60 40M
    4 10 75 65M
    5 0 200 200M

    My experience with the Color 3 head is slightly different, though. I
    have an RH Designs Analyser Pro, and have carefully calibrated it and
    the Color 3 head to each other. I'll post my report from that
    exercise next...

    -tih

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