problems with dunco enlarger

Discussion in 'Enlarging' started by paapoopa, Oct 3, 2012.

  1. paapoopa

    paapoopa Member

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    recently manage to get hold of a dunco enlarger. I believe it is the color head, it has 2 knob on the left adjusting exposure and on/off filter and 3 knobs at the right adjusting cyan magenta and yellow.

    everything seems to be in order, but when I am doing some test strip, I doesnt seems to be getting any contrast when I am printing on multi grade paper. I have tried various method,
    - adjust magenta and yellow on the enlarger
    - switching everything off on the enlarger and use the ilford multi grade filter method
    but all my prints turn out the same with no contrast.

    I couldnt figure out what could have gone wrong. will need to consult all the expert here. I am hoping that it is just some minor stuff that I miss out or did wrong.
     
  2. BMbikerider

    BMbikerider Member

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    A colour enlarger will also have a 'white light lever' which you can move so that the image is brighter to aid focussing, It will be on the side of the head. Find this lever and move it to the opposite end of the arc to where it is now and check the brightness on the base board. If it darkens then that is your problem.

    I use an LPL enlarger which is not all that different and found when I got it there had been little use for a very long time and the colour filters in the head were sticking this may be what is happening with yours, however I would go for the white light lever first and see if that works.
     
  3. ic-racer

    ic-racer Member

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    Is your print developer fresh? What developer are you using? What paper are you using?
     
  4. paapoopa

    paapoopa Member

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    Ya, I know what you mean when you say the 'white light lever' as I am use to kaiser VPM6005 enlarger which has that lever.
    I would reckon the knob that on/off the filter to work the same. and it kindof does. and I am quite sure that i keep tha filter on the ON side.

    I also tried ignoring the color filters all together and use the more older way of holding the multigrade filter under the lens which doesnt work out as well.
     
  5. paapoopa

    paapoopa Member

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    I am using ilford multigrade paper developer with ilford ifostop for stop bath and ilford rapid fixer for fixing. Printing on ilford multigrade RC paper.
    All Ilford products as those are the ones that is most easily access to from where I am. And there are all bought fresh.
    I have also test out the papers on another darkroom that I have access to just to confirm that the pack of papers are not foggy.
     
  6. ic-racer

    ic-racer Member

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    How long are you developing? 2 minutes minimum, yes?
     
  7. paapoopa

    paapoopa Member

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    yaa, i develop it for 2 mins, I have tried 1 min as well as I am mixing 1+9 for the developer
     
  8. paapoopa

    paapoopa Member

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    heres a picture of my setup if it helps identify some obvious problems

    8078900984_d510fe087d_c.jpg
     
  9. Trond

    Trond Subscriber

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    I also have a Dunco enlarger, although with the combined Multigrade/color filter module. But it's difficult to say what the problem is since you are saying that you have problems both when using the built in color filters and the Ilford Multigrade filters.

    Are you sure that the filters lift in and out of the light path as they should? You can check this by taking the top cover off. The filter module can also easily be taken out the head, that might make it easier to identify problems.

    What kind of Multigrade filters have you tried? Are they old?

    Trond
     
  10. paapoopa

    paapoopa Member

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    Hi Trond

    what do you mean when you say
    Are you sure that the filters lift in and out of the light path as they should?

    is yours the same model as the one I have?

    i have tried using both ilford multigrade filter which is not too old and kodak multigrade filter which is very old. both doesnt gives me good result.
     
  11. MartinP

    MartinP Member

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    Apart from the filtration, it is possible that you are getting some fogging exposure from the light bounced from the white walls. That would give unwanted tone to the highlight areas in your prints and thereby reduce the overall contrast. A couple of large pieces of black card or thin foamboard, behind and against the wall to the side of the enlarger, would reduce that problem considerably.

    Check that the projected image actually changes from "white" (used for focussing) to "filtered" (yellow-ish or magenta-ish depending on what you dialled in) when you operate the colour-filter lever.

    Most colour-head enlargers do not have a filter-drawer, because the condenser head is usually completely replaced. Without a drawer, how were you using the multigrade filters? The under-lens filter set from Ilford has a very good holder and robust filters, but the usual above-lens filter squares are an imperfect solution for regular use under the lens. That said, it should still let you get some sort of result.
     
  12. pentaxuser

    pentaxuser Subscriber

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    If I have understood everything you have said then the problem cannot be connected with the enlarger. It has to be either the developer( exhausted?) or the paper ( very old MG which has lost all its contrast?)

    With simple white light from the lamp and under the lens MG filters then unless the above are the problems you will get different contrasts with different filters, unless of course all the filters are so worn that none can effect the paper.

    None of what I have said sounds likely, I know, but I cannot see any other explanations

    pentaxuser
     
  13. kevs

    kevs Member

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    Apart from what the others have said about the enlarger filtration, lightstruck paper etc, other issues might affect contrast:

    Freshness of developer - should be made up fresh for each session. Developer, especially diluted, can quickly oxidise (exhaust) if not kept in an airtight container. Make sure you tighten the top on your stock bottle properly - better still transfer it to a reliably airtight bottle; fizzy drinks bottles work very well - with usual precautions if you have children/vulnerable adults around. If stock dev looks dark brown it's probably oxidised and won't work properly.

    Temperature of developer; developer should be at around 20c, if it's cooler you should develop for longer than 2 minutes (and always develop to completion; don't snatch the print early!) - it should still work though.

    Contaminated developer; developer contaminated with stop bath or fixer will show signs of exhaustion (see above).

    Good luck,
    kevs
     
    Last edited by a moderator: Oct 13, 2012
  14. paapoopa

    paapoopa Member

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    thanks, I think that what I will need to try next, puting some black mounting board against the wall.

    on my test, I tried handholding it below the lens for just a temp solution.
    I have also try putting the filters on top of the neg, so its in between the light source and the neg
     
  15. paapoopa

    paapoopa Member

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    Hi
    I am using fresh developer, stopbath, fixer and paper.
    I have also test my papers in another darkroom that I have acess to just to make sure they are not fogged
    I too cant find any explaination as I have done so many test to rule out the issues on certain things. I am going to try what Martin suggest next, hopefully that is the cause of it.
     
  16. pentaxuser

    pentaxuser Subscriber

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    I am going to sound like a very negative party pooper here but I wonder how much store you can put by the white background fogging explanation. I have a matt white background behind my enlarger( Durst 605) and have never seen the effect you have of getting no change in contrast.

    Set up everything in advance then switch all lights off. Put a sheet into an easel or just under the enlarger then expose sections or use two sheets of paper if easier at two extremes of contrast and process( you could even do the processing in darkness until the fix stage) and see if you obtain a difference.

    If this cures the problem then all I can say is that you must have an incredible light reflection from the background.

    Yes I know a lot of books recommend painting the background behind the enlarger matt black and if the problem is reflection then this should work but I do have doubts if your problem is as bad as you say.

    I take it that you have eliminated light leaks from the enlarger actually shining directly onto the paper? When you switch on the enlarger look under the lens. Are there any light leaks from where the lens screws into the plate attached to the bellows?

    It is the complete inability to get any contrast differentiation at all that I cannot figure out

    pentaxuser
     
  17. MattKing

    MattKing Subscriber

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    I was recently in a friend's darkroom. The friend had adjusted the three rotary dials on the colour head on the enlarger to zero (or so the friend thought), for the purposes of doing some tests. The results of the tests were very strange - almost no contrast in some cases.

    After trying to figure out the cause of the problem, the solution finally presented itself.

    The "yellow" rotary dial wasn't set to zero - it was instead set to maximum, which was far enough past the maximum setting as to appear to actually be set to zero.

    So check the yellow filtration.

    I won't identify the friend, because they post here :smile:.
     
  18. piu58

    piu58 Member

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    You get more contrast if you use more magenta filtering. MAximum magenta (130 or 170, depends on the enlarger) gives pretty contrasty images. I rarely use more then 60.
    The exposure time should me so long that the clear film base gives a deep black. Therefor it is a good idea to include the clear edge of the negative in the test strip. If you use a shorter time you get nowhere in you imgae a deep blacl. If you have that deep black, but the highlights are grey, you need more contrast, more magenta.
    It may be a good idea to use 1+4 devleoper. This gives arond one grade more contrast.