A neglected delight.

Discussion in 'Talk About Large Format Gear' started by David M, Feb 22, 2018.

  1. David M

    David M Well-Known Member Registered User

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    Bosscreen?
    I found it very difficult to use one of the very bright screens. It was marked Ebony, although the camera wasn't. I could only use it by keeping one eye closed, the spectator point was so critical. Very disturbing to have the screen go dark if I moved my head. Perhaps this is peculiar to my own eyesight, as other people seem to find no problem and evidently like the effect.
    Perhaps a fibre-optic screen would work, but fibre-optics of that size would be fabulously expensive.
     
  2. Ian Grant

    Ian Grant Active Member Registered User

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    The Bosscreen is a laminated screen, given a choice I'd go for a Beattie or a Maxwell. I did check with Teamwork for a replacement Wista screen thinking maybe I could fit it in my Crown Graphic it was over £70 + vat back in 2007.

    Screen choice is personal, not everyone likes a fresnel, It's possible to make a very fine bright screen (as might be found in a 35mm SLR but the "spectator point" you talk of David is more critical and the screen will go dark in places as you move your head, adding a fresnel prevents that. The only time I make extra fine screens is for TLRs etc. Acid etched screens are very bright but prone to the effect you're experiencing.

    Ian
     
  3. David M

    David M Well-Known Member Registered User

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    I like the Bosscreen under the loupe for its lack of grain. I believe they're out of production now.
    I've made couple of replacement screens that seemed brighter than "ordinary" ones. Just the usual method: two bits of glass and an abrasive. I found that I preferred WD40 as a lubricant, because water seemed to turn the abrasive into a sticky paste that was harder to move around.
    Spectator point is a term from measured perspective drawing. I suppose eye point might be better for photography.
     
    Last edited: Mar 2, 2018
  4. David M

    David M Well-Known Member Registered User

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    On another forum (Phototrio) I found this, concerning Maxwell screens:
    "...he has enough material for about 6 more screens in 4x5 and then that could be it. Reason being is that his supplier is no longer offering the material and the place he sourced a replacement from is in Europe so it might make selling the screens difficult due to a considerable price increase.." This was dated 4 March 2017. There are no more details of what this material might be. I had assumed that they would be injection moulded, although precision cutting is not an impossible alternative. Diamond tools can give a perfect finish.
     
  5. mpirie

    mpirie Member Registered User

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    Wasn't the Bosscreen made from two thin sheets of glass with a layer of translucent wax in-between?

    I seem to remember there being problems with them in high temperatures (not a situation for us in the UK at the moment) :cool:

    I have a Bosscreen on my TK2000 and a Maxwell on my Ebony.

    Mike
     
    Last edited: Mar 2, 2018
  6. Alan9940

    Alan9940 Active Member Registered User

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    Yes, that's correct. It provided for a near grainless and quite contrasty view. I never owned one, but I read of problems with the wax due to higher ambient temps. And, I'm not talking ridiculous temps like what we get here in the US desert southwest, but even in the 32 - 37C range. For that reason alone I never bought one.
     
  7. mpirie

    mpirie Member Registered User

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    Ah, well living in Scotland, it's not an issue I'm likely to have to deal with!:eek:

    Mike
     
  8. Ian Grant

    Ian Grant Active Member Registered User

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    It's not the - 37º C :D It's the 55ºC max temperature that Maxwell screens can't cope with, but air temperatures in the 30º to early 40º C are quite different to the heat objects may reach in intense sun.

    I was very surprised on Friday to find my greenhouse was very warm in or near the 20's when it was -3ºC outside, it was sunny :D

    Ian
     
  9. Alan9940

    Alan9940 Active Member Registered User

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    :D :D

    Yeah, it wouldn't be an issue for me, either, when I lived in central Vermont, USA. Ten months of winter and two months of darn poor sleddin'!! ;)
     

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