A linen tester is a strong magnifier with a measuring scale and a built-in stand. The linen tester was invented to check the quality of woven fabrics. It is used in the textile industry to measure the number of

weft Warp and weft are the two basic components used in weaving to turn thread or yarn into fabric. The lengthwise or longitudinal warp yarns are held stationary in tension on a frame or loom while the transverse weft (sometimes woof) is draw ...

and

warp Warp, warped or warping may refer to: Arts and entertainment Books and comics * WaRP Graphics, an alternative comics publisher * ''Warp'' (First Comics), comic book series published by First Comics based on the play ''Warp!'' * Warp (comics), a ...

threads within a certain area of fabric. Today, it is more commonly used to measure the line width and check the registration of color separations in the field of printing and publishing. It consists of a strong magnifier and a glass disc which has a measuring scale engraved in it. Nowadays, the scale is usually divided into

millimetre 330px, Different lengths as in respect to the electromagnetic spectrum, measured by the metre and its derived scales. The microwave is between 1 meter to 1 millimeter. The millimetre (American and British English spelling differences#-re, -er, ...

s; older linen testers had an

inch Measuring tape with inches The inch (symbol: in or ″) is a unit of length in the British imperial and the United States customary systems of measurement. It is equal to yard or of a foot. Derived from the Roman uncia ("twelfth") ...

scale. Simpler models have a square opening in the foot, with a scale applied to one or more edges of the opening. Linen testers are also used in other branches of industry. For example, they can be used to measure the line weight of barcodes.

References

*{{cite book , isbn = 978-1-103-41317-1 , url = https://books.google.com/books?id=Pto1M4NVeFMC&pg=PA19 , page = 19, title = Manipulation of the Microscope , first = Edward , last = Bausch , date = August 2008 Magnifiers Linen industry Printing Quality control nl:Loep#Dradenteller