Did I get a densitometer I can use?

Discussion in 'B&W: Film, Paper, Chemistry' started by RobR, Jun 27, 2003.

  1. RobR

    RobR Member

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    Greetings!

    After all of the discussion about my cheap, misguided effort to determine film speed, I checked E-Bay as I do every lunch hour. Lo and behold, there was a Beseler PM2M "analog densitometer" being offered with a minimum bid of $60 and no bidders yet. Loer and beholder, two hours later, it was mine!

    Now, the question remains: Can it do what I want it to do? Can it tell me if I've got a density of 0.11 over film base and fog?

    Thanks!

    Rob, who has a whole bunch of stuff waiting to be put out on E-Bay. Anybody want a Rodenstock Rodagon 135-mm f5.6 lens? New style, immaculate glass, very slight dent in the filter ring.
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    Well, you bought what was a very nice color analyzer in its day, not a densitometer.

    You can calibrate it to do B&W, and those modules can be configured as presets for your favorite color or B&W tones, but it won't give you standard density readings.

    One caveat that usually applies to analyzers of that vintage (I have a less fancy one)--don't turn it on with the roomlights on or you can damage the sensor. It should only be turned on in the darkroom under enlarger light.

    If it doesn't come with a manual, you may be able to get a photocopy from Beseler (or whoever owns them now) or from www.craigcamera.com.

    If you really have no use for such a thing, Columbus Camera should be able to nullify the sale, since they made an error in the listing, and I've had good dealings with them in the past. On the other hand, it's not a bad color analyzer for $60.
     
  3. Jorge Oliveira

    Jorge Oliveira Member

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    I'm glad I've used buy it now on a Ilford EM-10 - you could have purchased it (-:

    I don't know how good a densitometer it is - but from what I saw in the NET, it should allow for exposure time determination (at least a near figure) and choice of paper grade (so, poor man densitometer) using an auxiliary nomograph curve.

    Let's wait and see.

    Jorge O
     
  4. Ole

    Ole Moderator Staff Member Moderator

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    Jorge -
    was that by any chance my posts you read on that other site? :wink:
     
  5. Jorge Oliveira

    Jorge Oliveira Member

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    Ole,

    No, but if you can give me a pointer I would like very much to see it.

    Thanks,

    Jorge O
     
  6. Ole

    Ole Moderator Staff Member Moderator

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  7. Jorge Oliveira

    Jorge Oliveira Member

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    Thanks, Ole

    You article is very clear on what one can use the EM-10 for.

    I believe it was this APUG thread that arose my interest in a possible inexpensive way to save paper, so I went to Ebay and there was this EM-10 on auction.

    I did a Google search and found on this first page this Polish site, and due to my knowledge of Polish I downloaded an English document: (-:

    http://fox.vis.pl/filmy/ilford/em10graph.pdf

    Nice explanation on how to use the EM-10

    Printed it, studied the graph, made sure the salesperson would ship internationally and bingo - buy it now - $23 incl. shipping...
    I usually wait to the end of an auction - I'm a proud sniper, but sometimes making sure one get the goods is worth more than a few dollars.

    Jorge O
     
  8. Ole

    Ole Moderator Staff Member Moderator

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    Thanks for the link, Jorge!

    My graph was hand-drawn, and my emphasis was a bit different: Everything is based on 10s exposure with very light gray (zone VIIĀ½?) placed at a reading of 85 or thereabouts. I then read midtone and shadow: Midtone to select the paper type, shadow to select the grade. Then dial in filtration, adjust aperture and ND filtration to put the very light gray back where it belongs.
    I also have readings of a projected Stouffer grayscale, and prints at 10s on more than 20 paper/grade combinations...
     
  9. ann

    ann Subscriber

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    I used one for years for this purpose. I had a set of negatives that had been calibrated for me and this allowed compare. There was no way to get a specific numberical value, but it was getting me in the ballpark /
     
  10. mikepry

    mikepry Subscriber

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    A neat little trick that I learned to do that is to get a .10 density filter from Kodak and with a spot meter on a tripod aim it at a constant light source and taking a unexposed DEVELOPED neg with the 010 filter sandwiched on it make a reading. there is your .010 above fb+fog. It is great for finding a working speed for your film doing the zone one test. A bit crude yes but it will bring you very close to where you need to be for a fraction of the cost and a real time saver due to the simplicity factor.
     
  11. Jorge Oliveira

    Jorge Oliveira Member

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    This thread is becoming very interesting - lots of tricks!

    So there goes another one:

    I have a very simple enlarger - Opemus III, no filterhead, etc.
    Using VC filters is not a problem - they can be placed between condenser and neg carrier - but no ND filter...
    Yesterday I've just installed a standard light dimmer inside my EPOI enlarging timer (sure, one can use an external unit - but this way is neater) so the elarger lamp can be fine tuned to the light I need.

    Comments?

    Jorge O
     
  12. Ole

    Ole Moderator Staff Member Moderator

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    I'm "double-calibrating":
    I have an Opemus 6a with colour head, which includes an ND filter along with the common C/M/Y. Great for fine-tuning exposures. But only up to 6x6...

    I also have a Durst 138S with condensor head. I use this with grased paper, or hand-held Cokin filters under the lens (!). This seems to give an adequate range with most VC papers. I have test-printed the paper/filter combinations with the step-tablet in the negative carrier; without, with yellow, and with magenta filter. All at the same time and aperture. That way I know exactly how the filters influence the exposure. Exposing to desired contrast grade is done by simple (mental) arithmetic... It's a kind of split-grading, except that I use unfiltered and either yellow or magenta filtration. So far, it seems to work - to my considerable surprise!
     
  13. glbeas

    glbeas Member

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    Yup, dimmers will change the color temperature of the light and result in having to fine tune your filtration for every setting of the dimmer as the blue component of the light fades. An ND filter is really the best way to get rid of too much light. ND filters should be fairly easy to find.
     
  14. Jorge Oliveira

    Jorge Oliveira Member

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    Glbeas

    I see your point.
    However, I've decided to give it a try since:
    - I have no other way to fine tune light output at this time (I don't have a Vc head).
    - Adjustments will be minor - say +/- 0.5 f stops.
    - If you take the spectrum of an incandescent lamp and of a cold light source, they are quite different, but there are no different VC filters for each of these light sources, so maybe that's not a major issue.

    Next time I do prints I will let you know.

    Jorge O
     
  15. glbeas

    glbeas Member

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    Good, Jorge! I wouldn't ever say you can't make it work, but the variables will make life interesting. I'd mark the positions of the dimmer, or better yet put a volt meter on the line and work at "standardised" voltage levels so you will know what point you are working from. As the voltage drops the bulb output will redden fairly fast. Let us know how this progresses.
     
  16. glbeas

    glbeas Member

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    A cold light does need a yellow filter of a some value I can't remember added to it to get in the proper range for VC filtration. Otherwise you have to calibrate and disregard the numbers on the VC filter and figure out the grade you are getting by comparing the results to graded paper.
     
  17. Jorge Oliveira

    Jorge Oliveira Member

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    Ok, I'm really not familiar with enlarger's cold lights - that was my guess.
    I do know that standard fluorescent lights 'daylight type' 6400K (AKA cold light) have two main lines in the green (strongest) and blue wavelenghts, so it would make VC paper soft...
    I thought enlarger's ones were a somewhat special.

    Now, some practical data:

    I've just made two small enlargements of the face of the Sculptor (see gallery).
    One was 9s@f5.6; the other one ended at 10.5s@f4 - so, a bit over 1 f stop light reduction using the dimmer.
    My reference was the white mark at his forehead, filter grade 3, Polymax II paper.

    Yes, there is a diference if you put them side by side - but I would say less than 0.5 grades.
    So, I believe that for 0.5 f stops (my intended usage, 1 f stop I get from the lens), it will be insignificant.

    Thanks for your comments,

    Jorge O