More to like about Leica

In case you haven't seen this -- do view the brief video as well.

 

Link Leica's Factory Workers Look Like They're in a Futuristic Sci-Fi Movie - Core77

This is typical for clean room manufacturing. Workers wear lint-free gowns, hair and beard coverings, and gloves. Notice that the sleeves have a tight cuff. Skin sheds a lot of particulate, and it's better to avoid contamination of the optics than to attempt to clean them later.

 

The rooms are pressurized so that all air movement is outward. Halls themselves are at higher pressure than ambient air (or the non-aseptic areas of the building. Air supply to the assembly rooms are filtered through HEPA filters, which remove particles larger than about 5 microns (for pharmaceuticals. Assembling digital sensors would have much lower thresholds. Air flow over the work surfaces would be laminar (straightened with grids) to eliminate turbulence, which would mix with dirtier air.

 

I am mildly surprised that workers are using finger cots rather than gloves. But then, we're not seeing the most critical parts of the assembly process.

 

(I spent a large part of my working career designing, building and testing clean rooms.)

Why you shouldn't put an exhaust fan in a darkroom.

Why you shouldn't put an exhaust fan in a darkroom.

I'm not sure an exhaust fan would be detrimental..

 

The exhaust fan in a darkroom is to provide ventilation, and remove fumes from chemicals. Dust is only a problem from dried spills, which can be eliminated using due diligence in handling, and prompt cleanup. Dust on dry film can be removed by brushing or with canned air. Dust on lenses has no noticeable effect on the results. You don't need a big fan. One room change every hour would be better than most offices, and probably overkill in the absence of nasty stuff, which belongs in a hood anyway.

 

Dust on wet film is a problem, but greatly reduced if you use a surfactant rinse and squeegee the film as it hangs to dry. A drying cabinet should use filtered air.

 

Compare this to dust between layers of a sensor, or inside a lens. If you pay good money for a lens, you don't want to see dust inside where you can't clean. A small amount probably doesn't affect the image, but it's bad for customer relations. Even microscopic dust inside a sensor will be easily visible, and present in every image.

I agree with Ed. In my opinion, the easiest darkroom or clean storage improvement is a light industrial air filter (with induction motor) on a 24 hour timer to give 20 minute bursts of filtration a few times per day and night. At least that way, you enter a relatively clean environment before you do anything else. I have clear polyester (Mylar/Melinex) rolls that have been effectively 'dust free' for 7 years or so, and nothing in the store ever requires dusting. When I had a darkroom,

I made sure the filter would not whip up air currents while the darkroom was in use, and used an extraction fan & filtered drying cabinet.

I knew a lens repair technician who previously had significant dust issues and swore by this kind of filtration.

I was thinking of dust coming under the door and from various cracks in the walls and ceiling and wherever else the makeup air is coming from when an exhaust fan is running.

Cut a hole in the door and install a filter and light baffle. Install a door sweep to exclude light and air flow.