RE: Mercedes Coverslip Tape

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From:"P. Emry" <> (by way of histonet)
To:histonet <>
Content-Type:text/plain; charset="us-ascii"

I am in a small research lab and would not need a machine for taping, but
can the tape be used by hand?  If so, where would I get the tape.  Sound more coverslipping.  To good to be true?

U of Washington, Seattle

On Wed, 27 Jan 1999, Tim Morken wrote:

> Gary,
> While I agree that for high-magnification critical microscopy and
> photography a glass coverslip will be the best, for surgical pathology
> and the vast majority of microphotography the tape is just fine. I used
> this method for several years in a past job and nobody complained about
> it. I was hesitant to use it but the fact is that even a very fussy
> pathologist who publishes practically daily never even noticed when we
> changed to the tape. So, for practical purposes in a heavy-workload
> pathology lab the tape is fine. And I doubt that glass coverslippers
> will ever match the speed, which is the tape machine's primary
> attraction.
> Tim Morken, B.S., EMT(MSA), HTL(ASCP)
> Infectious Disease Pathology
> Centers for Disease Control
> MS-G32
> 1600 Clifton Rd.
> Atlanta, GA 30333
> email:
> FAX:  (404)639-3043
> ----Original Message Follows----
> Date: Tue, 26 Jan 1999 13:25:19 -0500
> From: garygill <>
> Subject: RE: Mercedes Coverslip Tape
> To: "Hagerty, Marjorie A." <>,
>  'Histonet' <>
> Marg:
> 	It sounds as though you already have a Sakura machine and you're simply
> price comparison shopping.  If you don't already have a Sakura tape
> dispenser, however, please read my post below that was originally
> submitted
> to Histonet 1/7:
> 	Cover glass acts the first lens in any microscope objective, and is so
> considered by lens designers.  There are specific refractive index,
> dispersion values, planoparallelism, and thickness specifications for
> cover
> glasses that plastic cover glasses can not match.  It is not enough that
> a
> specimen, whether cells or tissue, be covered by something thin and
> transparent.
> 	Most often No. 1-1/2 thickness cover glasses are recommended in
> publications.  Such recommendations are based on the interpretation of
> the
> thickness printed on the objective itself (e.g., 0.170 [meaning 170
> micrometers thick]).  art of the cover glass.  No. 1/1-2 thickness cover
> glasses are correct only when there is little or mounting medium between
> the
> specimen and the underside of the cover glass (e.g., cells grown on a
> cover
> glass, specimen mounted on a cover glass, spring-loaded clothes pins or
> weights applied to the cover glass to squeeze out the excess mounting
> medium).  Such applications are research oriented and not practiced
> routinely.
> 	In practice, the thickness of mounting medium between the specimen and
> the
> underside of the cover glass is often substantial and acts optically as
> though it is glass.
> 	Many years ago some authors actually cross-cut some histo slides and
> measured the thickness of the mounting medium, finding it to be
> substantial
> relative to allowable deviation tolerances.  The upshot of all this is
> that
> No. 1 thickness cover glasses should be used routinely.
> 	4X and 10x objectives are insensitive to cover glass thickness, due to
> their low numerical apertures.  40X acrhromat objectives can tolerate
> deviations only as small as 15 micrometers.  What happens when overly
> thick
> mounting medium and cover glass are applied?  GLARE.   High dry image
> quality loses contrast, appearing cloudy, hazy, washed out, etc.  The
> greater the thickness, the worse the appearance.  The cleaner the
> microscope, the closer it is set up for Kohler illumination, the higher
> the
> quality of objective (e.g., planapochromat), the more obvious the loss
> of
> contrast appears.  If one practices sloppy microscopy, the loss of
> contrast
> will be less obvious.  Is the loss of contrast ruinous?  Will it prevent
> one
> from making a diagnosis?  No, but plastic tape is a triumph of
> technology
> over technique.
> 	Bottom line:  Sakura plastic tape can not equal glass cover glasses
> applied
> by any man or machine.  However, if saving money is your primary
> goal...?
> At one lab where I worked, the Sakura machine was sometimes used,
> sometimes
> not.  The surface of the mounted tape was wavy, and often pulled up at
> the
> edges.  High dry microscopy of cells along the edges was often
> impossible.
> Some dotting inks used in cytology etch the plastic and can not be
> removed.
> Also, the tape scratches rather easily, further scattering light and
> introducing glare.  Cytology preparations are less forgiving than are
> histo
> ones.
> Gary Gill
> -----Original Message-----
> From: Hagerty, Marjorie A. []
> Sent: Tuesday, January 26, 1999 12:25 PM
> To: 'Histonet'
> Subject: Mercedes Coverslip Tape
> Hi All,
> Does anyone know anything about the coverslip tape from Mercedes
> Medical? They have tape for the Sakura coverslipper that costs less than
> the tape from Sakura. I am interested to find out if anyone has tried it
> and how they liked it.
> Thanks,
> Marg
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