Help Using graded paper with multigrade head

Discussion in 'B&W: Film, Paper, Chemistry' started by Fintan, Apr 6, 2008.

  1. Fintan

    Fintan Member

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    I've an ilford multigrade 500 head and am using an rh designs stopclock 500 with it.

    I want to use a graded paper, oriental seagull g3 this afternoon and not sure what grade to set my stopclock 500 to. I haven't used any graded paper in a long time...

    The multigrade manual gives grade 4 1/2 but I'm unsure if this is best with the stopclock 500.

    Anyone any ideas while i'm off to mix chems :confused::confused::confused:

    Fintan
     
  2. snallan

    snallan Member

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    I have no experience with either the ilford head, or the oriental seagull.

    But, I do use a De Vere with their multigrade head. And in a little experiment with Adox Nuance g3 found little difference between exposure at g2, or at g4, this was using a set of exposures to determine the max flash at each grade setting.

    The main difference exposing at g4, and you will probably find this worth having, was the paper was slightly more sensitive. The first patch of tone showing earlier (though only by about 1/6th of a stop), and the gradation in the first few steps being gentler than the exposures at g2. After three or four steps the tones were coming closer together.

    It would be worth doing this for the oriental seagull with the 500 head, to see if there is a worthwile difference between them.
     
  3. GM Bennett

    GM Bennett Member

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    Hi, Fintan -

    I have the MG500 Head and the RH Analyser 500. I use a setting between 4 and 4 1/2 with good results for graded paper. As I understand it, the graded paper is sensitive to blue light, which explains the high contrast setting on the controller. Cheers, Graham
     
  4. fschifano

    fschifano Member

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    No matter what settings you have dialed in, the contrast should not be affected. If you dial out all light to which the paper is blind, and ONLY the light to which the paper is blind, exposure times will be unaffected. I think you'll do just fine if you dial out all filtration and just use the white light setting, if one is available.
     
  5. E76

    E76 Member

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    I would just use white light as well. It has been my experience that using filtration along with graded paper does absolutely nothing other than increase exposure times.
     
  6. tiberiustibz

    tiberiustibz Member

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    Graded paper does not respond to filtration. You can try. If it responded it would be called multigrade, that's the point.
     
  7. PhotoJim

    PhotoJim Member

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    The different settings will affect the length of time you need to expose the paper (as blue light is increased or decreased), but otherwise, if you adjust the time accordingly, will not affect the printed image.

    Ideally, turn off filtration, if possible, to minimize exposure time.
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    All graded papers that I have tested, have been blue and green sensitive, so if you use any filter at all, you are losing a stop in speed. It is therefore best to remove the filtration from the beam. The VC enlargers that I have worked with have a zero filter lever or a zero filter setting. You should use that for optimum performance.

    As to anyone who might question the statement, I have just tested Kentmere #2 grade paper and found it has green sensitivity. I got the same result from other brands.

    PE
     
  9. dancqu

    dancqu Member

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    Likely none will question. Although a generalization, a study of
    Graded paper spectral sensitivity will show a tapering off as the
    500nm and up range is entered. Importantly for safelight use is
    how little sensitive is the paper at those wave lengths. I use
    Emaks, Kentmere Bromide, and Slavich under yellow-ish
    orange safelights with no problem. Dan
     
  10. Photo Engineer

    Photo Engineer Subscriber

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    Dan;

    The yellow safelights can allow light from about 580 nm out to 700 nm depending on safelight. I would have to look it up to give you the exact value, but some graded papers have sensitivity out to 540 nm. This is plenty of room for safety. But, all sensitivities 'taper off' on both sides of a central peak. So, blue sensitive papers taper off, as would a red sensitive paper. There is nothing unusual about tapering off in sensitivity, so I'm not sure what you mean.

    All I point out is that if you use a magenta filter in the beam, or a yellow filter in the beam, you are losing speed equivalent to the density of the filter divided by about 2. That is why I suggest white light.

    PE
     
  11. RH Designs

    RH Designs Advertiser Advertiser

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    I would suggest setting a hard grade - 4 or 5 even. The Ilford head uses two lamps with green and blue filters, and our StopClock 500 controls these independently to produce a split-grade exposure. It's not possible to get white light from the Ilford head (unless you remove the filters altogether). We haven't actually tried graded papers but given that they are mostly blue-sensitive, setting a hard grade will minimise the use of the green lamp. Maybe PE can offer some more advice given the above product information, although I entirely agree that it's largely pointless to use any filters for graded paper if you have a white-light source. Ron, do you think the green sensitivity is generally sufficient to make it worthwhile using the green lamp as well as the blue?
     
  12. Fintan

    Fintan Member

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    Thanks Richard, I appreciate your advice.

    Fintan
     
  13. Jim Noel

    Jim Noel Member

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    Graded papers are blue sensitive only. Set your head so that it projects only blue light.
     
  14. gainer

    gainer Subscriber

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    There are two factors involved if you are using a photometer to set the exposure: the color sensitivity of the paper and the color sensitivity of the meter. My advice is to set the light's color at white and calibrate the meter so that you know the exposure values (light * time) that produce the steps of a projection step wedge. The paper does not have a sharply defined band pass. Limiting the color of light to blue will cut off some of the light to which the paper is sensitive without any benefit to the purpose at hand. Exposing with or without a filter will have no effect on contrast. Just remember that the object, if you're going to use a meter, is to "teach" your meter to see as the paper does.