Arthur,
Thanks for your reply and tips. Your explanation makes sense. Actually, I
have a refurbished $30 flatbed scanner that has the same problem - just much
worse. I opened this scanner to clean the inside surface of the glas bed.
After leaving the scanner on for a long period of time (1 day or so) with
the lid closed the fog appears again. Leaving the lid open or even turning
the scanner off helps some. So I guess they used really cheap material that
cannot stand the quite high heat produced inside this scanner. Maybe that's
why the company who made the scanner doesn't exist anymore...:O
Rob
>-Original Message-
>From: [EMAIL PROTECTED]
>[mailto:[EMAIL PROTECTED] Behalf Of Arthur Entlich
>Sent: Tuesday, November 04, 2003 3:02 AM
>To: [EMAIL PROTECTED]
>Subject: [filmscanners] Re: CanoScan 9900 & "Dirty" Glas Plate
>
>
>This problem is often due to the plasticizers or mold release agents
>evaporating from the plastic surfaces from heat after the scanner is
>built. SOmetimes even the materials used in packaging the scanner may
>off-gas materials that deposit of the glass bed.
>
>These scanners travel by slow ship and often go through considerable
>temperature changes.
>
>First, make sure the fogginess is on the inside surface, by carefully
>cleaning the outer surface well.
>
>As to how much the fog degrades the image, it somewhat depends upon the
>degree of "fog" the type of lighting and image sensor, and the thickness
>of the glass. If there is an area, as you indicate, which is not foggy,
>you may wish to scan the same material in different areas of the scanner
>and see if the results are different, keeping in mind that all flatbed
>scanners have a "sweet spot" where they scan the best (usually a column
>down the center of the length of the scanner bed).
>
>The bottom line is that scanners really shouldn't have residue on the
>internal glass surface, and this should be covered by warranty. You
>might try an exchange and see if the next one is cleaner. Sometimes
>service techs will end up removing the fog during a cleaning but add
>other dirt or contaminate the image sensor. These scanners are put
>together by robots and people in clean rooms (in theory, at least) and
>whenever they are opened, the risk of new dirt entering exists.
>
>Art
>
>
>Robert Meier wrote:
>
>> I have just purchased a CanoScan 9900. After installing the unit
>I realized
>> that the glass on which the film/document is placed is "foggy".
>You can see
>> this best when the scanner light is on and look almost parallel
>to the glass
>> plate. The part closer to the back is more "foggy" then the
>other side. Also
>> there is a small clear part so it's definitely not just a property of the
>> glass. Has somebody else discovered that on this particular
>scanner or other
>> scanners? Is this typical? Does it affect image quality from a practical
>> point of view?
>>
>> Robert
>>
>>
>
>---
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