Maintenance of focussing screens

I've recently switched to using Hasselblad 6x6 from Bronica 645. I now

use the waist level finder instead of a prism. I really enjoy the WLF

but I find that the focus screen acumulates dust, marks etc. which,

due to the delicacy of the screen is best lest alone. I am

considering the purchase of an upgraded accute matte screen at some

cost however I am wondering how other blad users keep their focus

screens in good condition. I find marks on the screen annoying as

they may mask small details that need to be corrected in the scene

when taking the photo. To be honest I am also wondering if it's worth

buying a new screen or a significantly cheaper used one that a bit

beaten up already.

Tony,

This is THE standard problem (other than lateral inversion, which is a "feature" ;-) ) with a WLF. I use a blower brush from time to time. With the built in magnifer in the hood, the problem becomes significantly worse because you are now seeing every dust speck 3x life-size. I have learnt to live with it.

One thing to remember is that the Hassie screens, (old version & acute matte, are a sandwich of 2 components, a glass upper plate (closest to your eye) and an acrylic (or some sort of plastic) layer into which the fresnel grooves are impressed. Most dust & debris accumulates on the upper glass side. This can easily & safely be cleared away, as the above poster suggests, with air, and also with the same techniques you'd use to clean lens surfaces.

The well known caution about the delicacy of the screens is particularly valid to the under side, in the body. But since this is also best protected from the elements, it shouldn't be a big source of dust accumulation. In other words, you can be a little more robust in your cleaning methods on the upper glass plate.