1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
  2. REMINDER

    Any content, information, or advice found on social media platforms and the wider Internet, including forums such as AP, should NOT be acted upon unless checked against a reliable, authoritative source, and re-checked, particularly where personal health is at stake. Seek professional advice/confirmation before acting on such at all times.

Enlarger Troubles

Discussion in 'Help Team' started by JayRo, Nov 17, 2017.

  1. JayRo

    JayRo Member

    Hello Help team,
    I've recently rediscovered my love for B&W film photography and managed to score a load of second-hand darkroom gear for a really great price, so I built myself a darkroom in the garage. I've spent a good chunk of the last few months locked away developing loads of film and many great prints (to my eye, anyway). The only problem I had was that I was unable to print any of the photos I have taken on my old Agfa Synchrobox, which takes 120 film. To my great delight, last week I spotted an old Meopta Opemus 5 enlarger with a colour head in one of my local op shops, going for a bargain price (still in its original case an everything)! Only thing is, there are a couple of problems with the enlarger...
    First, as the light source is a 100W 12V halogen globe, it needs a transformer to run. It did not come with the transformer, but I was able to get a 105W 12V downlight transformer from my local electrical supplies shop. That seems to have worked OK, and the globe is glowing strongly, however, the light coming out of the lens seems a bit dull, and is decidedly dark around the edges. I took apart everything that I could and gave all of the glass and lenses a good clean, but it hasn't made any noticeable difference. I also went out and purchased a new globe to see if that would help, but no luck.
    I wonder if anyone out there might know what's causing the darkness around the edges of the image?
    There is one part within the colour head that could be the culprit... A spherical part that the light source gets reflected into horizontally, which then reflects the light 45 degrees to vertical... but I can't figure out how to get it open to attempt to clean it.
    Any help will be greatly appreciated!
     
  2. Andrew Flannigan

    Andrew Flannigan Well-Known Member

    My first guess is you’re using a 50mm lens. You need a 75mm lens to cover 6x6 (or a 60mm wide angle to forestall the smart Alecs).
     
  3. taxor

    taxor Well-Known Member

    The lens seems the likely culprit. Like the previous poster says, try a 75 or 80mm lens. Personally, for 6x6 negs I use a 105mm mm lens because it'll do 6x7negs as well. Does the enlarger use different light-boxes for different formats? I had a Durst colour enlarger years ago which required one to change the light-box (not sure if that's the actual name) when changing format.
     
  4. PeteRob

    PeteRob Well-Known Member

  5. PeteRob

    PeteRob Well-Known Member

    A random thought, it being many years since I used an enlarger, are the lenses in the condenser properly located? Their job is to diffuse the light source evenly.
     
  6. Roger Hicks

    Roger Hicks Well-Known Member

    It is possible to install the mixing box backwards on the Magnifax (6x9cm version of a Meopta) so check if this is what has happened. There is a hole in the box and obviously it needs to be opposite the aperture for the bulb. I only discovered this last week l after 20 years of using Magnifaxes... The mixing chambers also come in different sizes (at least for Magnifaxes) and a 35mm chamber would vignette on 6x6.

    Cheers,

    R.
     
  7. JayRo

    JayRo Member

    Hello everyone, and thanks so much for your replies! I've done lots of tinkering over the weekend, and after hooking up to my third transformer, I have come to the conclusion that I've got two issues... First, the halogen globe I'm using is just not bright enough. The light coming through even when I have it set up for 35mm negatives enlarged to 8x10 is taking huge exposure time even on full aperture on the 50mm lens I have (almost 2 minutes to get a crappy quality underexposed print!). I've ordered a higher wattage bulb, so hopefully, that will help.
    Also, as noted above, I do need a wider angle lens to print 6x6 - after reading the manual properly, it states that an 80mm lens should be used, so I'm on the hunt for one that will fit!
    Again, thanks for all your help,
    Jay
     
  8. PeteRob

    PeteRob Well-Known Member

    What aperture are you using? What paper are you using? What developing conditions are you using?

    - enlarger lenses have variable aperture.
    - if you have a colour head but are using multigrade paper for mono then the filtration is critical
    - if you develop for too little time or too low a temperature you won't get an image
     
  9. Andrew Flannigan

    Andrew Flannigan Well-Known Member

    On that point: I always developed to extinction. The last few years I was wet printing I used the Nova upright tanks which make it much easier to stick to the rule because you can't see the image coming up. And have you tried the coin on the paper check of your safelighting?
     
  10. PeteRob

    PeteRob Well-Known Member


    I haven't printed for years but, for mono anyway, watching the image appear is "the magic" that makes the effort all worth while. I can't imagine giving that up! I never attempted colour.
     
  11. JayRo

    JayRo Member

    Hi, as I stated in my reply above, I had the lens at full aperture - sorry, don't know the number on that lens, but it was as wide as it could get! I was using multigrade paper, but I bypassed the colour head filters for the time being, and was using an Ilford multigrade number 4 filter. The developer was a fresh batch and it was around 20 degrees (give or take a couple of degrees - as per manufacturers recommendation). After all that, and with a ridiculously long exposure, I ended up with an image that was much lower contrast than expected. When I compared it to the image I get from my Durst B&W enlarger, much shorter time (around 15 seconds from memory at full aperture) and much higher contrast - as expected.
     
  12. JayRo

    JayRo Member

    Hi, I tested my safelights when I built the darkroom, as I went a bit unorthodox and used red LED strip lights. I had read about using them, but wasn't sure that they would work, but I has some LED strips already, so I did the testing that Ilford recommends on their safelight datasheets, and it turned out that red LEDs work perfectly :)
     
  13. PeteRob

    PeteRob Well-Known Member

    I hadn't realised you were used to the darkroom.

    The Meopta manual says the enlarger uses a 100 W bulb with transformer for colour head and 150 W opal bulb with the mono head. It gives a photo of the standard opal bulb but not the colour head one.

    Did you get a replacement bulb made for enlargers?

    I found this one on SpeedGraphic site but no spec on power output or enlarger compatibility. It appears directional. If your globe bulb (not a term I recognise) gives light in all directions that could be a reason for the low light output.

    A1/231 100w 12v Xenophot Lamp Bulb
    Cold-light 100w halogen lamp for use with darkroom enlargers equipped with a suitable transformer.
     
  14. JayRo

    JayRo Member

    Great news! I picked up a new lamp from my photographic supplies shop today, and things are looking much better! All I need now is an 80mm lens for the enlarger and I can finally print my large format negatives...
    Thanks for all the advice!
     
    Roger Hicks likes this.
  15. PeteRob

    PeteRob Well-Known Member

    That's good. It is a nuisance that something boxed up would be missing essentials.
     
    Roger Hicks likes this.
  16. David Loxley

    David Loxley Well-Known Member

    Sorry Pete I disagree. I most early enlargers the lamp was held on the end of a tube which stuck out through the top of the lamphouse. It was held by a clamp screw and could be moved up and down. The pair of condenser lenses formed a very short focal length convex lens. The job of the condensers was to focus the light source in the iris of the projector lens. This way the maximum amount of light passed through the lens. If one moved the lamp, on its mount, up and down and looked at the light pattern of the easel one could see that the light pattern varied from a heavily vignetted circular patch through a quite evenly lit patch and back to heavy vignetting. The little formula:- 1/f = 1/u + 1/v is the secret. F = focal length of the condenser combination; u = distance between the condenser lens plane and the light source; v= distance from the condenser lens plane to the plane of the projector lens iris. So every time one moves the enlarger head, focus an image on the easel one must also alter the position of the lamp.
    This does not apply to diffuser or cold light enlargers

    D.Lox.
     
    Last edited: Mar 27, 2018

Share This Page