The L-201 is probably one of the most familiar designs of microscope, available to the world. It has its roots in a British Design Patent, which eventually came to be manufactured in China, as manufacturing industry declined in the United Kingdom, during the trend of globalization in the 1970's and 1980's.

The Guangzhou Liss Optical Instrument Factory, which is now the Guangzhou Liss Optical Instrument Company, plays an essential role in supporting merchants throughout the world, with optical products of exceptional quality. Forthwith I refer to this manufacturing source in China, as GLOIC.

Ask anyone to describe what they envisage a microscope to look like and the picture they would present would be something probably approaching that of the image shown, which is a Euromex Model SE. 5225, with traditional square stage. The Euromex Model SE. 5275 has a round, adjustable stage, and neither of the Euromex brands of the L-201 based designs, in the Euromex S series ships with a condenser, or the range of optics which extends the L-201 to about 2000 times magnification.

The Paralux brand of the L-201 microscope is actually a GLOIC L-201A.

Obviously there are a few differences between the Paralux and Euromex brands, but the inconsequential differences between Black or Silver, trims and knobs, is less important than ensuring that the power of the lens is good enough for the tasks placed before it.

The Paralux L-201 Brand has a Paralux Model number 6202, and ships with more powerful lenses than the Euromex S series, and it also has a round stage and underside condenser.

Identification of a GLOIC microscope is achieved by inspecting the top of the Stem. Original microscopes made by GLOIC carry a plate mark indicative of the production locale.

This is usually a logo, and also, a trade mark, that is proudly placed upon the device by its creators to indicate the care and attention the product received in genesis. A genuine GLOIC microscope carries the logo shown.

Quite often it is said in support of branded products, that foreign imports, outside of Europe, are inferior copies of Western products, but, while that might be true of produce in the I.T. industry, it does not appear to be true of the optical domain: quite often the reverse is true.

The original L-201 microscopes, as they have shipped from Guangzhou, China, to the West, came supplied with a Wooden box, optical objectives of 4x 10x and 63x and a full range of eye lenses, 5x 10x and 15x, and an Abbe condenser. Branded products may differ to this. This is because, for the greater part of the past 40 years, much of China has been manufacturing these products on behalf of established suppliers, who place orders for vast quantities of a product, tailored and specifically branded to merchant specifications.

Many of the original L-201 microscopes were distributed by small, independent traders and retailers, who preferred to stock GLOIC products, because they were made available to their distributing networks and because they tended to offer, exceptional quality, unparalleled by the branded products of their price bracket.

Many of these shops were specialists, or independent Camera shops, who stocked GLOIC Microscopes for their customers to buy because they knew that there was a common source of manufacture, of both branded, and unbranded, products from China: in point of fact, while I was engaged in trying to obtain a source for a manual for the L-201, one large distribution company responded to my enquiry, by openly and overtly stating, that my attention would be better placed contacting Microscope product manufacturers directly, which they said, in the greater part are largely all located in China! Of these, GLOIC is the Grand Daddy of production facilities: they manufacture, assemble, and distribute parts to other assembly plants for bespoke microscope designs.

Production of the L-201 in Guangzhou has largely been superseded by production of the L-301, which is the same base model but has a quadruple turret, which takes 4 objectives. It is perfectly possible to upgrade the L-201 to the L-301 standard by upgrading the rotor. Many of the accessories which are available suit both models.

The current GLOIC model L-301 looks much the same as the Brunel Wedmore microscope, but I am advised by Brunel, that the Wedmore, is, in fact, not a product they source from GLOIC.

From my personal observation, I can see that the stem of the eyepiece of the Wedmore, is a little longer than that on the L-201, and that the Wedmore has a different design of stage to the L-201.

That being said, I dare to suggest that many of the accessories available from Brunel, would also be suitable for GLOIC L-201, and the L-301 instruments.

Details of the Wedmore range are available from Brunel here, for education here, and from UKGE here.

Although there seems to be trends towards newer, safety first, designs of microscope, with stages that move with respect to a stationary stem, for all its advantages, I still consider the traditional design of the L-201 with a stationary stage, relative to an adjustable stem, better suited to work which involves micro manipulation tasks.

The most recent European distributor of GLOIC L-201 microscopes is Alaska Paralux of France. The Paralux product page for the L-201 might have been found at the L-201 product page and has to be reproduced here as a reference to the compatible Paralux accessories range.

The Paralux L-201 data sheet might also have been found on the Paralux site page, and is reproduced here for reference also.

An English L-201A manual, based upon the French Paralux L-201 6202 brand, is available for print and electronic reference from this site or from Paralux direct (they had my consent to distribute in support of the L-201 product English user base). (Special thanks is extended to Christophe Lavanchy, at Paralux, for sending me a Paralux French version to translate). The French version is available from Paralux France direct, so please contact their technical support, as I don't have rights to openly distribute the French version myself: the French manual is not my own work.

• Paralux L-201 English Electronic manual.
• Paralux L-201 English Printable manual.

The Electronic edition of the manual is straight forward enough, all pages are arranged to view in order. The print version of the manual is designed to form a 16 page booklet. Please don't email and ask me to rearrange the pages in another order, they are correctly arranged as they appear in the file. Here are my findings on this matter.

For some reason, different printers, render the file to print in different configurations, so getting the booklet to print correctly is much dependent on your arrangement of hardware, for example, printing with a HP laserjet, using Acrobat Reader 5, seems to render the booklet as you would expect: set the output to print 2 pages to 1 A4 sheet, 1 page at a time, keeping the orientation of the page the same in one plane, but presenting the blank reverse side of the previous page for double sided print, once you have produced 1 hard copy, running off 50 thousand in the photo copier is not going to be a problem, but its getting there, if you like, you can put a bit of Monty python music on in the background, it will probably take you two hours and a Christmas tree to get there!

HP laserjet printers appear to grant full options to get the printed page orientated in the way you might expect. With Epson printers, and I don't know quite why, but my Acrobat Reader 5 version, does not allow the swapping of the pages around at the printer driver command level, so better results are achieved by orienting the file so that the back page appears first (top), and then the front page (bottom of sheet 1). This is achieved in Acrobat 5 by turning the print so it appears upside down before printing (rotate page 90 degrees twice in Acrobat); if you don't, the booklet you get will open the wrong way around. This is not a Epson print interface matter, I have always found their printers the best, and most other software packages allow for full options at the printing level and it is possible to select what page appears top, or bottom in 2 to 1 mode, except, for some reason, Acrobat Reader 5. I guess they have a preference to HP. This might not be the case with Acrobat Reader 4, or some other Acrobat Reader versions. In short summary, I have printed the manual using an Epson, using my original copy file, and after printing the copy through to a Acrobat pdf file and turning it upside down. I have also printed the pages with a HP. So it, IS, possible to create a booklet from this PDF file, but I am afraid you will have a bit of fun and games learning quite the exact way your setup will allow it: just like me! My apologies for that, there is not much I can do about the inconsistencies that abound in I.T.

Please don't email me with requests for English translations of other Microscope manuals, TEFL is not my business, or my hobby, and neither is I.T.: my linguistic efforts were a grace and favour action, extended as an enthusiast of microscopy, in support of the L-201; it seemed to me right that GLOIC having supplied me with such a decent product, and the French having blessed us with Pasteur, that the English speaking world should be blessed with a decent manual.

• GLOIC Microscopes
• The L-301 (replaced the L-201)
• Accessories
• Contact details

Their network of specialists are more than capable of ensuring despatch of completed orders, support, servicing and calibration of all of their products for Institutional and Academic use. Personal enquiries from individual end users will probably be redirected to smaller distributor specialists. And please don't forget that China is a massive place, and also a very great distance from Europe and the Atlantic, so if you approach Chinese vendors direct, don't be surprised to find that they will probably require a reasonable size order to make shipping the goods worthwhile (i.e. >£100, or $200.) China prefers US dollars for international trading.

GLOIC also offer a great range of accessories to complement their L range of microscopes. It is possible to obtain, digital cameras, software for PC, and all sorts of fixtures and fittings, polarizers and phase contrast sets, objectives, and measurement optics, to upgrade the L-201 for any functional use, with only one caveat, YOU ARE REQUIRED TO KNOW THE PRODUCT YOU WANT TO BUY and its Part reference before approaching any Chinese vendor, import export specialist, or optical distributor. If YOU get the order for the product wrong, that is not THEIR problem. As with any production base, the Factory supports its own product range, but refers small orders to distributors, so make use of the GLOIC site for reference to compatible parts and accessories, and don't waste their valuable time without an order.

Another useful associative reference for GLOIC instrumentation, is Ningbo Yuda for professional, medical, hospital, educational and academic supplies of Optical equipment and the products listed here. The Ningbo Yuda catalogue is also available from their site. Ningbo Yuda has a sister company that supplies commercial products for the consumer market called Ningbo Yujie and it is worth visiting their General microscope product page, L-201 microscope page, L-201 microscope specifications, Microscope accessories page, for information relating to their assembly version of the L-201 microscope, as some of the parts for this model, like the mirrors, are compatible with the GLOIC model.

If you have never purchased direct from China before, the whole experience can be quite daunting. Individuals in the UK tend to think small, China is massive, and its production capacities are huge: obtaining parts from a number of different sources would tend to increase the shipping costs, so it is usually better to approach a specialist in the particular field who can collate the items together, deal with all the necessary payments and ship them to your locality.

Basically there are two options, you can approach a specialist in your host country, or you can approach a specialist in the country of manufacturing origin. If you have absolutely no clue what you need, and how to do business with China, then it is probably better to approach a specialist in your own country, but usually they will advise according to their current contact network of supplies.

Personally, this was not an option open to me: nobody in the UK specialized in the GLOIC L-201 model or accessories for it. So I approached Mr J. Wu of L & W Optics Electronics Co., Ltd.

Mr Wu's company operates from a region very close to the GLOIC factory and so it was possible for him to receive and despatch an order as a GLOIC distributor. I found Mr Wu took care in every aspect of his service in ensuring all parts were exactly despatched to match my requirements.

When extending the magnification range of a microscope, by increasing the power of the lenses, it is important to ensure that the optics are matched to minimize further focusing adjustment. Because Mr Wu's company is familiar with the L-201, it was not a problem to match a high power 100x objective with the correct 35 mm parafocal length to match the existing set of lenses on the L-201. The company also collated parts from Yujie/Yuda and the GLOIC, and were able to supply a replacement mirror for the L-201. Jack Wu was accurate in every detail of my order and requirements and so I don't have a problem in personally recommending his company as being the experts they are for the product.

Lighting is an important part of microscopic study. Unless your expertise extends to fluorescent work, and necessitates the use of the Ultra Violet or Infra Red range, WHEREABOUTS SPECIAL SAFETY PRECAUTIONS ARE NECESSARY TO PROTECT EYES, and INDIRECT OBSERVATION IS BETTER THAN LOOKING DIRECTLY THROUGH THE MICROSCOPE LENSES, then you will probably be wanting to select decent illumination accessories to support your studies.

When selecting illumination for microscopy, you will be attempting to ensure that the light shown to the eye, and the specimen, peaks to a Zenith, about and around, the colour white you choose, and with spectral losses to a NADIR about the regions of black light radiance of Ultra Violet and Infra Red which damage the eye: but the problem is, white is not a colour, because it contains every colour of light in the spectrum.

Despite the existence of a Geneva convention which prohibits anyone from causing any kind of deliberate visual impairment, most people I have encountered in the UK are pig ignorant to Colour and Colourometry, and Eye Safety pertaining to Black radiance: even those practising in Optometry, and Optical transmissions, or under the spotlight of photography in the media, save for Tussaud's in London, who expressly forbid any flash photography on their site. It is unacceptable practice to simply flash out the Hi Tones of eye sensitivity of the Public domain of the UK, simply because one or two large communication companies want to make use of an optical frequency for their optical communication networks, or mis-represent inaccurate, slow, java intensive search results, on the Internet, and force people to stare at screens, for longer periods of time, by obscuring information they require.

As white light contains all wavelengths of light, lamps are usually classified by their colour temperatures, rather than by the wavelength of light they produce. This is usually indicated in Kelvin, and is a measure indicative of the spectral tendency of white light towards the red or blue extreme of the spectrum. The colour temperature of normal daylight varies, according to the placement of the sun on the horizon, and the clarity of the atmospheric conditions of the day.

The most discriminating images through optical systems is achieved by a tendency towards the blue end of the visible spectrum, at the expense of the colour balance to red, people tend to speak of light peaking in this region as colder. But to ensure the visibility of all spectral components of a subject under study, it is also necessary to achieve an even spread of light upon the object. I am not about to make a suggestion about the best light to use for your particular area of interest, but by consulting specialist web sites it is possible to know the colour temperature of the light that best suits your need.

The traditional way of choosing a lamp is by using a colour chart standard:

• RCA CIE 1931 standard
• CIE1931

It is also possible to calculate the colour temperature of white light directly as Mike Guidry reveals on his site:

• Mike Guidry's Colour temperature reference.

Spectral emission of Light Emitting diodes is regulated by several standards which may be consulted for reference:

CIE/ISO Led Standards

• CIE 127 LED measurement standard.
• TC 2-45 Recommended geometries for luminous flux and intensity measurements on LEDs.
• TC 2-46 Standards on LED Intensity Measurements.
• TC 1-62 Colour Rendering of White LEDs.
• TC 2-50 Measurements of LED clusters and arrays.

By using Mike Guidry's online Applet, I was able to easily derive that the spectral bandwidth of light in the visible spectrum ranged from 4100 degrees Kelvin at the red extreme, to 7100 degrees Kelvin at the blue end. Although one would readily expect White light to exist at around 6100 degrees Kelvin, in point of fact, the colour temperature best suited to achromatic lens systems, is achromatic light which nears the equilibrium of energy of spectral emissions at about 5000K.

Personally, I choose the LAI-1 (LAI and LED 1 cluster) from GLOIC, which consists of a switchable Annular LED illumination cluster (4424721), and a Power supply (4421511). This unit was supplied to me by GLOIC by Mr J. Wu of L&W Optics Electronics Co., Ltd. The unit offers ranges of light in Colour temperatures from 5000 Kelvin to 5500 Kelvin. It was originally designed to grant overhead lighting to the stage of a single lens optical microscope system by direct attachment to the microscope.

I did not consider electrical attachments to a microscope, a very good plan, but as the LAI-1 comes with clamps and a hole wide enough to be supported by a standard Radio Spares gooseneck microphone stem, it can be readily adjusted to present light from a variety of angles to anywhere about the microscope as a separate item.

The power supply can be adjusted to switch light to a combination of rings, expanding and contracting the light source, and the intensity of light can be increased according to the task. Simply put, these GLOIC products are proving extremely useful, not only for microscopy but for other craft work too!

If you have found the information on this reference page about the L-201 microscope, of more use to you than a wet Sunday search by a google bot devoid of a decent index, and like me, you have, for a long time, wondered about the strange London Underground type markings on the stem of your microscope, or indeed, if you have any other comments to make or advice about extending the L-201, then please feel free to post direct. I am sorry but I cannot address questions and specific advice pertaining to eyesight other than suggesting to wear grade 1 (with the slightest tint) UVA and B sunglasses while using a microscope, for protection and to prevent the eye piece lens from steaming up.

NB: The L-201 microscope is currently available and being distributed in Europe at
http://www.ol-optic.com/microscope-paralux-l201-p-1207-30_76.html