Cleaning Hasselblad Focusing Screens

Discussion in 'Medium Format' started by rob_martin|5, Dec 29, 2005.

  1. Not so much a question as simply sharing a very stupid thing I did
    recently...

    I bought a "new" 503CW on ebay, and it was nearly immaculate except
    that the focusing screen was rather filthy--not scratched in any way-
    -just dirty. It actually looked as though someone had sneezed on it
    or something. I figured it would take a bit more than simply
    blowing it off with a duster, and I'd read that these screens are
    acrylic--not glass; so, lens cleaner would be a no-no. I decided to
    very gently wash it under warm running water with mild soap. It
    cleaned up quite nicely with no resulting scratches. The problem is
    that I hadn't realized that these screens apparently consist of two
    plates that are sandwiched together. Rinsing the screen under
    running water resulted in water/moisture being trapped between these
    plates. It's difficult for me to describe the appearance, but it
    seems to be slowly clearing up. I did this several days ago, and
    the adverse effect is all but gone now. I'm hoping it will
    completely clear up, but it's been a slow process.

    Dumb, dumb, dumb thing to have done, and I just thought I'd share it
    so someone else doesn't try the same thing. It might have (and, may
    still) cost me a new screen.

    Rob
     
  2. Don't beat yourself up: be patient -- water evaporates!
     
  3. Rob
    If the marks don't all disappear trying washing it again in distilled water (often aso sold as De-ionised water)This should dry completely clear as it will have no minerals in it.

    Advice for anyone else in the future. A cotton bud damped with distilled water probably would have done the job better.
     
  4. cpj

    cpj

    Stand it on EDGE, behind window glass, and where it can get some sunlight. (Glass filters
    ultraviolet light) Don't let it get "hot" but a couple of hours ought to drive out the water
    vapor that's trapped. It should be no problem unless you got some soap in there. If you
    have soap stains, then the distilled water suggestion is the way to go.

    For the future, there is a product out called "iKlear Apple Polish" which is sold in a pump-
    misting spray bottle and has no harmful stuff in it. It is designed for computer screens and
    especially Apple Computer flat panel displays found in their Powerbook portable
    computers. It works great and I use it all the time on my "plastic" eyeglasses as well as on
    the computer. It comes with a very fine, lint-free wiping cloth about 12 x 12 inches. Use
    only a very small amount. Check it out at www.KlearScreen.com

    PETE
     
  5. I have the same experience like Rob but I later found out that you can take the pair of plates out of the metal frame which holds the two plates together. Then you can clean each plate separately. Of course you need to put them back together in it's original sequence and direction otherwise focusing will not be accurate.
    Happy New Year.
     
  6. Interesting, Chenwah...I hadn't considered taking such a risk (e.g., deforming the frame structure, introducing dust between the plates, etc.). However, at this point the odd effects continue to linger with no apparent signs of further improvement. So, I just separated the plates, and I'm going to attempt to wash them with distilled water and see what happens.

    Rob
     
  7. But be careful!<br>You know how much these thingies cost. And while the plastic bit is fairly 'safe', the glass is rather thin. The frame will never fit together as snug as it did originally, but that may be just a matter of cosmetics. Unless it is just that bit too much out of shape. Then it will be a matter if out-of-focus.
     
  8. Phew...well, I think I got it back together pretty well enough; and, it does look a whole lot better. In fact, aside from one tiny speck of dust I allowed to get between the plates, it looks as good as new. After so much handling of each piece, though, I'm only 99% sure I reassembled it correctly. The etched surface does go on the outside (facing downward, toward the mirror), right? I couldn't tell a difference in surfaces of the thin plate, but I think I replaced it as it was originally. I know it lies on top (as the screen sets in the camera). The camera appears to focus normally, although, I'm new to MF and don't have much of a point of reference. I'm finding it generally difficult to focus anyway but figure this just takes a bit of practice/experience.

    Rob
     
  9. Rob,<br><br>It certainly sounds like you got it the right way round, yes.
     

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