www.pentrace.com - The Site for Fountain Pens that Write
Articles in Full
Home Page
Go to Message Board
Join the SnailMail Group
Reader's Corner
Submit an article for publication
Bureau of Weights and Measures
Reference Section
The PenMarket Message Board

about the Pentrace site
Biographies of Pentrace Contributers
Links to other resources
Contact details for Pentrace.com
Previous articles and older stuff
Message Board Archive


Related Links

* Q&A discussion

Nibs under the microscope!
Nib images from a Scanning electron microscope
By Bruce Robinson

This is first of a series or articles which will examine nibs and their shapes in detail. Bruce gives an introduction to the Scanning Electron Microscope and shows some preliminary images to give you an idea of what this equipement is capable of. A Q&A will be run in conjunction with this article, to participate please click on the link in the related links box on the left..

Scanning electron microscopes have been available since the mid 1960s.They can achieve much higher magnification and have a better depth of field than optical microscopes. This is an big advantage for examining large curved things like nibs.

SEMs work by firing a finely focused beam of electrons, in a vacuum, at the sample. The beam is rastered sequentially across the surface of part of the sample. Some of the electrons are reflected back from the specimen, detected and displayed to form the enlarged image direct on a computer screen, and captured digitally. Sadly, electron microscopes only work with monochromatic electrons (of one energy), so the pictures are inherently black and white. There are techniques for later colouring the images.

As well, the beam of electrons can be used to analyse non-destructively individual points on the sample, for instance, to identify the elements present in the "iridium" on the point, and the differences in composition where the "iridium" is welded to the gold of the nib. This is because the impinging electrons interact with the elements present where the beam hits. The gold atoms emit characteristic gold X-rays and the silver and copper atoms emit silver and copper characteristic X-rays, and these are proportional to the amounts of each element present. The X-rays are collected by an X-ray detector attached to the SEM.

A relatively hard part of imaging the nibs is getting an evenly illuminated image, without some sections being too bright and some parts being in the darker shadows.

Chosing the correct angle to show the aspects desired is also a challenge.

Logically, an SEM in Australia can now be operated directly over the Internet, or the images viewed remotely in real-time from the US or anywhere. However, SEMs are common in Universities and research laboratories, so there should be some in most major cities.

The illustrations show some preliminary images from a recent Pelikan Script 1.0 mm low-price pen (sort of calligraphy) in image1, and a standard Sheafer NoNonsense Fine Italic (which I bought second-hand on Sunday for Aus$2. The Sheaffer is much squarer ("Italic") image2, and the Pelikan much rounder and "Stub". The nibs are mounted upside-down, and we are looking straight down at the underneath of the nibs.

One advantage of the SEM is that one can measure the dimensions relatively accurately from the scale on the images(at least laterally in the image if not vertically), and there is a good idea of the shape, and the smoothness.I suspect that the very fine scratches and features are not as important in nib-smoothness as the actual shape and other factors. Obviously experts like John Mottishaw who work with a good optical microscope will have a very good feel for the parameters that matter.

Comment on this article...




[ Home | Message Board | SnailMail Group | Reader's Corner | Submit Article | BoWaM | About | Biographies | Contact | Older Stuff ]
Copyright 2000-2001 pentrace.com, All Rights Reserved