[filmscanners] Re: SS4000 again

["Arthur Entlich" <artistic-1@shaw.ca>]

Hi Cliff,

I think the majority of the information you indicated is very well to
heeded.

However, anti-reflective coatings typically do not come off by cleaning,
not any cleaner that anyone would dare use on a glass lens mounted in a
painted or plastic mount, at least.  Anti reflective coatings are
usually vaporized metal which create a type of diachronic surface that
is obviously very thin not to alter the color or contrast.  Perhaps
acids might remove it, or an abrasive, but they are really almost
integrated onto the lens surface.

What is more likely to have occurred is he/she smeared the surface and
any residue on it (like oily substances from either lubricants within
the machine, or vaporized oils from contaminated atmosphere) and that
could lead to flaring, because if the anti-reflective coatings get
coated with contaminants which aren't fully transparent, creating a
"surface" to the lens which captures some of the image into that layer
and that will lead to highlights having halos. Just like a dirty car
windshield only seems obvious when the sun shines through it.

The same can occur to a mirror surface, but the added risk with a front
surface mirror is that the vapourized metal surface on them is very
vulnerable to micro-scratching.

What I have found works best for lens surface cleaning is a very clean
and virgin (never used for any other purpose) natural chamois, like
those car finish zealots use to dry and polish their cars with.

If you have ever looked at one of those "lens pens" you will find it
uses a small piece of chamois on a rubber backing, and the chamois is
impregnated with graphite as a lubricant.

OK, now I have used the terms virgin, rubber, impregnated and lubricant
in the same posting, so I'm going to take a cold shower ;-)

Art


Cliff Ober wrote:

> Rob,
>
> I have done it. I may have disassembled mine farther than absolutely
> necessary in the process, but I did get a pretty good look at all of it.
> The CCD is actually mounted at a right angle and is unlikely to have
> much if any dust on it. The only thing you need to worry about cleaning
> is the mirror. It must be done delicately since it's a front surface
> type. There is also a lens in front of the CCD that must not be touched
> - PERIOD. Do nothing more than blow it off. I know someone else who
> tried to clean that lens on his machine and had all the anti-reflective
> coating wipe off onto the swab he was using. His machine still works,
> but has some flare problems with high contrast images. If you're
> reasonably competent mechanically you should be able to handle
> disassembly. Be careful removing the cover - it's attached to the
> chassis by wiring for the buttons and LED's on the top.
>
> Cliff Ober
>
>
>
> Rob Geraghty wrote:
>
>
>>I gather nobody on the list has attempted to clean the CCD of a SS4000?
>>
>>Rob
>>
>

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