Using colour head and confused

Discussion in 'Enlarging' started by leeturner, Jan 28, 2006.

  1. leeturner

    leeturner Subscriber

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    Hi

    I've finally got a darkroom up and running for the first time in 5 years. In my previous darkroom I had a simple condensor with under the lens MG filters.
    I managed to get hold of a couple of Durst Mod70 enlargers with the colour heads plus and old L1000 that I'm fixing up.

    Last night I tried printing for the first time with the Mod70. I was under the impression that MG paper printed at a default grade (is it G2?) with no filters. So I tried a print with the colour box switched out and the exposure times were much faster than what I was used to e.g. 4 seconds for an 8x10 from a 6x6 neg. Much too fast for me. I then tried turning the lamp down but still not much luck. I then switched in the filters and adjusted them for a grade 2 and the times dropped to a manageable 9 to 12 seconds. Again I thought that with direct light MG printed at approximately grade 2 so are the filters (using Y and M) also acting as a type of ND filter? It looks as though it's going to take me a while to calibrate the filters to my purpose. Is is worth setting up the other enlarger with below the lens filters and adjusting the colour filtration to match these results or should I just do what I used to do and go with what looks right?
     
  2. Dave Miller

    Dave Miller Member

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    Yes, the filters will reduce the light and lengthen the exposure. Ilford give two sets of filter combination, one of which gives constant (but slower) exposure times around grades 2 to 4. The other set gives faster but varible times. I recommend that you use the first set that will allow you to step through the grades without varying times too much. Enjoy the experience.
     
  3. Bob F.

    Bob F. Member

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    If you do not have it already, pop along to http://www.ilford.com/html/us_english/bw.html - download and print the PDF document called "CONTRAST CONTROL" which has filter/exposure tables for the two methods Dave suggested.

    Cheers, Bob.
     
  4. leeturner

    leeturner Subscriber

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    Thanks Dave & Bob. I've already got the filter settings from Ilford and they have two settings, one for just the Yellow filter and the other for Yellow and Magenta. Is there a noticeable difference between the two and which is preferable? I'm certainly noticing the difference between the condensor and the dichroic head. It looks as though I may need to go a grade harder than I used to. Is this normal due to the diffusion? A lot of my old negs were developed as per manufacturers spec. If I understand correctly I need to increase development/contrast for a diffusion type head. Can some this be achieved in film rating and exposure (e.g. I normally expose HP5+ at 320) and then using normal dev times or is it purely down to development?
     
  5. Nick Zentena

    Nick Zentena Member

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    The dual colour filter numbers are supposed to be speed matched. Switch from grade to grade and you are supposedly able to keep the same exposure time. OTOH the single colour filter settings aren't speed matched. The single filters will also be quicker since you'll have less filter in the light path.
     
  6. Bob F.

    Bob F. Member

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    What Nick said re' the filtering... In practice, you will find you need to adjust exposure somewhat in any case because the different filter grades effect highlights and shadows differently, so the balance of light/dark is altered somewhat between grades.

    I have not made the switch from condensor to diffused, but my understanding is as you say: increase development slightly. From my limited experience (and a lot of reading...) I do not expect you will need to alter film speed as the increase in development will probably not be sufficient to change the toe of the film curve by much. However, if you find you are now printing on to grade 2 or 3 for most of your negs then you may as well stick with your development times as they are. But, I'd wait for more experienced people to chime in before I took my word for it... :wink:

    Cheers, Bob.
     
  7. leeturner

    leeturner Subscriber

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    Thanks Bob. I've seen the rather heated discussions about different types of light source and there is a noticeable difference, but let's not get into that old argument. One advantage I am finding is that the diffuser seems to lessen dust and the like on the neg. The room I have my equipment in is unfortunately carpeted but I have put a large antistatic mat down which helps to a certain extent. I'm working on "she who must be obeyed" to fit a laminate floor in the room but our priorities, as usual, seem to differ.

    I'll plug on for the next few days and hopefully wil be able to post some examples next week. One major advantage over my previous darkroom is that with lens prices at a ridiculously low level I'm now able to print with significantly better glass than before.
     
  8. Photo Engineer

    Photo Engineer Subscriber

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    Since every enlarger type has a slightly different color temperature due to the particular lamp used and the optics, the actual filters needed to attain a given contrast grade or color balanced color print will vary from enlarger to enlarger.

    Values given in tables are as useful as the 50R starting pack recommended for color paper.

    PE
     
  9. raucousimages

    raucousimages Member

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    Dump the color head and go back to VC filters. I tried to print B&W VC paper over the years with color heads (Vivitar, Omega and durst) with poor results. I always had less work and better results with VC filters. The only thing that comes close is my Saunders VCCE.
     
  10. Bob Carnie

    Bob Carnie Subscriber

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    Keep in mind that when changing Magenta filter you will be changing exposure.

    30 magenta change + or - will equal 1 full stop change in density

    15 magenta change + or _- will equal 1/2 stop change in density.
    Yellow filter does not affect the density as dramatically as magenta in fact very little.

    When using a dichroic enlarger, changing grades with yellow and magenta will require a understanding of this.
    I think this is why a lot of people advocate the RHAnalyser in use with a dichroic enlarger head.

    I use condensor heads with VCfilters and I really only notice a big density shift when going up to G 4.
    For diffusion I have a Ilford Multigrade head which has a keypad for density and contrast control and is easy to use.
     
  11. Kapten Stofil

    Kapten Stofil Member

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    See http://www.inbio.com/Your_home.html about good arguments for laminate floors instead of carpets. There is more muck in a carpet than you really care to know.
     
  12. Bob F.

    Bob F. Member

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    True enough, but see the link below for what can happen to your nice laminate floor if a pipe springs a leak under it at 2 a.m. and you need to get at the pipe quickly... :sad:

    [​IMG]

    I now recommend flooring you can pull up / roll back in the event of an emergency... :wink:


    Cheers, Bob.
     
  13. RH Designs

    RH Designs Advertiser Advertiser

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    Lee -

    Yes, the two filters will act as ND. The tables of colour settings that Ilford enclose with the paper come in two sets, one that uses just a single filter (Y or M) and the other that uses a combination of Y and M for each grade. We've found that these dual settings are quite a close match to Ilford's own below-lens filters, so if you want the minimum difference between your two setups I suggest you use these dual-filter settings. The single-filter settings will give you shorter exposures in the middle grades but require a lot more adjustment of exposure when you change the settings. You can (if you use the f-stop printing method) derive a table of exposure adjustments vs filtration which makes life easier.

    The business of "consistent exposure" from grade to grade with Ilford filters is a bit of a red herring as it refers only to a specific density (i.e. shade of grey). If you choose the exposure to get the highlights right, you can adjust the shadows using the filters. For example if at grade 2 the shadows aren't dark enough try a harder grade setting, and if they're blocked up try a softer one.

    I use a colour head perfectly successfully for VC printing. Some colour heads won't manage a full grade 5, only 4.5, but that's a minor inconvenience compared to the smooth and continuous control of contrast that you can't do with Ilford filters (unless you use the split grade technique).

    And don't forget that the correct "grade" is the one that makes the print look right, not a specific number!

    Regards
    Richard
     
  14. leeturner

    leeturner Subscriber

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    Thanks Richard. I looked again at the Ilford settings for the Durst. If using a single filter then grade 0 is indicated as 150Y with 5 being 170M. However using two colour filtration grade 0 is 115Y 0M and grade 5 0Y 170M. WHy the disparity when both settings for grade 0 are in effect using 0M? Is this so that exposure times for the next grade up using 2 colour filtration are not affected?

    With split grade printing would it then be correct to use the single filtration method as logically grade 0 and grade 5 are only using one colour.

    OT - wrt laminate floors, I've had the unfortunate duty to fit them in several rooms in the house. Much easier to clean etc. but a sod on the knees when fitting them.
     
  15. Nick Zentena

    Nick Zentena Member

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  16. dancqu

    dancqu Member

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    Nice thing about the Meopta Dichros; dial in ND. Dan
     
  17. RH Designs

    RH Designs Advertiser Advertiser

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    Lee -

    Sorry for the delay - computer problems. Yes, the discrepancy is in order to equalise the exposures as far as possible from grade to grade. With single colour filtration your exposures will typically be much shorter in the mid grades than at the extremes.

    For split printing single filters are perfectly adequate. On my colour head I simply use 200Y and 170M, the maximum in each case. If you're using Ilford filters, just choose grades 00 and 5.

    Regards
    Richard
     
  18. Timothy

    Timothy Member

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    A simpler and surprisingly effective method is simply to use split contrast printing for every print. Start with max yellow and aim for ideal highlights only. Then with that exposure given, test with max magenta, this time looking for shadow detail. Then make one "straight print" with no manipulation, just the max yellow and the max magenta exposures, and evaluate it for desired burning and dodging. Usually, some areas will want some burning with more yellow light and some may want more with the magenta. This is the method that I use and one of the advantages is that I never spend any time trying to figure out filter settings for "equivalent" contrast grades on different papers.

    Tim R
     
  19. leeturner

    leeturner Subscriber

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    I'm trying out split grade but the problem I'm having initially is the correct amount of grade 0. The two grades look OK as separate test prints but when combined seem a bit muddy. What I'm doing now is getting the grade magenta time and exposing a whole sheet with that time. I then expose a max yellow test strip on top of this to get an idea of the ratio. It's very early days for me in the darkroom and I'm sure it will get easier with experience.
    One benefit I'm seeing to split grade printing is it's helping me to identify problems with my initial film exposure as I can see deficiencies within certain exposure values. The other main benefit, as Dave Miller pointed out, is being able to dodge and burn highlight and shadow separately.

    I've posted a work print that I tried with split grade printing. It printed OK on grade 3 1/2 but the problem was if I tried to burn in the highkey areas is also burnt in the black accentuating the high key look.

    [​IMG]
     
  20. Bruce Osgood

    Bruce Osgood Membership Council Council

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    leeturner

    For what it's worth, this is how I make a split grade print:
    1) With max yellow filter I run a step table of time to determine the least amount of time to obtain a hint of tone in the highlights.

    2) With that time and filter I expose another entire strip of paper and then on top of that I do a step table of max Magenta filter to see what appears to be the best combined exposure.

    Do NOT do the second exposure separate of the first because when you combine them it won't be right.

    3) Now I make the first test print using the original yellow and the apparent magenta filter.

    To go further is to tweak the print and that is purely subjective. The point is that the most important exposure, the one that the entire print depends on as accurate is the yellow. All the time in developer, the kind of developer, all the way through dry down will depend the yellow exposure.
     
  21. leeturner

    leeturner Subscriber

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    Bruce, that's what it took me a little while to grasp. I was intially under the impression that the shadow detail would be defined by the magenta but found out that too much use of yellow just eradicated any definition within the shadow area.

    I'd just like to thank everyone for their help and advice, it's much appreciated.
     
  22. GeorgesGiralt

    GeorgesGiralt Member

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    Hi !
    First of all, if your color head does not have a density filter built in, you can reduce the lamp output by switching to a less powerfull bulb. There are 250 w, 100 and 75 w bulbs avail. of the same design. Downrating is safe (the other way is not, as the current is much higher and heat also came into play)
    If this proves insuficient, you can insert a piece of white translucent Perspex above or under the light mixing box in order to reduce lamp output. It's cheap, and esay to install and to change. Inspect it often because with heat, this material becomes yellow and will change the filtration unexpectedly.
    Next, without filter, you've got a quite grade 2 exposure, but the paper's speed if greater (see Ilford fact sheet for your paper). As a filter is put into the light path, it will absorb power so the light reaching the paper will be weaker, provided the filters are not worn out. (be carefull if you open the head for cleaning not to put things like WD40 on them, it will destroy the fine metallic deposit making them filters... Been there, done that...)
    And go to Mr Butzi web site (or others) and calibrate your dichro head to get proper grades with your setup. Print a grade/filters conversion table and you will have a speed matched head perfect for printing. You can calibrate it for every paper you use, different manufacturers have different "grade" meaning...
    Last but not least, consider printing with plain under the lens filters. If your enlarger head is not sturdy and stable, moving from one filter setting to another (say for burning in) during a print session will move the head and ruin the current print. It is much easier to change a filter in a filter holder than to ensure your head doesn't move during dial in. If your lens has a front filter thread, you can put a Cokin or Lee filter holder on it and use this as a filter holder for Kodak, Fuji or Ilford filters. Buy the under the lens type or the Agfa ones. They are made to go above or under the lens.