The PEAK Glass Scales are made from a high transmission glass strip, or a
transparent glass plate with gradations marked using a process of photo
etching and printing. It is very useful in any microscopy laboratory, both
as a magnification "anchor" for macrophotography and also for working with
stereo pairs in a stereo scope.The scales come either with a
separate 15x magnifying loupe or two built in 10x measuring loupes. In
other words, the purchaser is getting more a "kit" which contains the scale
plus the kind of magnifier needed for the proper reading of the scale. The
minimum scale division of all scale products is 0.1 mm.
Calibration of the glass strips is done at room temperature, however for
temperatures in the vicinity of room temperature, that is, +/- 10 C°,
the coefficient of thermal expansion is such that there will not be any
This variation of the product is for those making the most precise of measurements. It is especially useful in the photo etching and printing industries.
These high precision glass scales are checked with tools that are themselves
calibrated against NIST traceable standards. However, the data supplied
with these scales would not pass the test of being called "certified
standards." Quite possibly, SPI or some other qualified agency could
undertake to take a number of different measurements at different locations
on a particular scale, reporting not just the average result but also the
standard deviation of those measurements. But such additional measurement
would add substantially to the cost.
All three scales are 3 mm thick, 25 mm wide with varying lengths. For
easier reading of the scale, we recommend the Loupe/Magnifier 15X. The
style with the built-in measuring loupes are always 10x.