Pye Unicam

UV-Visible Spectrometry

The complete story of the development and marketing of UV-Visible Spectrometry at Pye Unicam to download. 

UltraViolet and Visible Spectrometry.pdf

Adobe Acrobat Document 267.5 KB

UltraViolet and Visible Spectrometry.pdf

With thanks and acknowledgements to Doug Irish (Pye Unicam).

Landmark UV-Visible Spectrometers

To view examples of early UV-Visible and other early Unicam Instruments product brochures please select this link

1940s - SP500

During and following the second world war in the 1940s, the UK was extremely short of money with which to buy American made instruments. We believe the UK government loaned Unicam a Beckman DU instrument for a weekend and in essence were told to copy it.

The Unicam SP500, and a new spectroscopic business, was born! The government also loaned an instrument to Hilger Ltd who produced a similar model- the UviSpec. Thus producing some healthy competition.

1952 - SP600

The success and potential of the SP500 led to the development of a somewhat more capable, and user-friendly UV-Visible Spectrophotometer – the SP600.

Launched in 1952, the Woolwich Arsenal chemical inspectorate were one of the first to review the instrument.

By 1967 the range consisted of the SP500 and SP600 manual instruments, together with the SP1300 colorimeter. Also making an appearance were the SP800 UV/Vis and the SP700 UV/Vis/Near-IR instruments.

1965 - SP8000

The SP8000 was advertised as the most versatile spectrophotometer available for UV and Visible analysis.

An integral flat-bed chart recorder for results and dual absorbance ranges of 0 to 1A and 0 to 0.2A were provided.

A large sample compartment provided a wide range of accessories including an autosampler. Automatic wavelength selection was available.

This completed the Unicam range of SP500 Series 2, SP700 and SP800, and the Queen’s Award winning SP3000 which had been project managed by David Shrewsbury.

1970 - SP3000

The SP3000 when launched was advertised as the world's first fully automatic digital spectrophotometer with a unique photometric system for the highest accuracy.

It provided automatic sampling, automatic wavelength selection, automatic calibration and measurement and automatic digital readout and printout.

It was offered with a host of accessories including the SP3002P automatic sample changer, the SP3013 automatic wavelength selector, the SP3001 digital printer, the SP3005 fast programmer and the SP3007 constant temperature cell holder

1972 - SP1800

During the early 1970s the SP1800 & SP1700 formed market leading products.

They also marked the start of using diffraction gratings rather than prisms as the dispersing element in the monochromator.

They were double beam instruments. Single beam instruments offered more light throughput, and hence better signal to noise ratio. However double beam importantly offered better stability by monitoring the light source variations.

The SP1800 had an analogue readout, the SP1700 a digital display. Project leader for both was Mike Sharpe.

1976 - SP8-100, SP8-200, SP8-250, SP8-300, SP8-400, SP8-500 Series



1976 saw the introduction of the SP8-100, SP8-200 and SP8-250. This family of double beam scanning instruments formed the backbone of the main Unicam UV/Vis instrument family for many years. They migrated into the 8-300/400/500 and 8800 series.

A large sample compartment facilitated a wide range of specially designed accessories. Mike Sharpe was project leader for the 8-100 and Tony Moss for the accessories.

The SP8-200, launched in 1978, led by Bob Francis, was the world’s first microprocessor controlled UV-Vis instrument.

The SP8-200 was a single monochromator instrument employing a master holographic grating for ultra stray light levels. The SP8-250 provided double monochromator optics for even higher performance levels.



1978 - SP6, PU8600 Series

The original SP6 with vacuum formed casework

The revised SP6 Series

By the 1970s the Pye Unicam SP600 was old technology with many competitors. The answer was the SP6, led by Bob Kydd with Ron Newstead providing design work.

Based around optics from the previous SP30, it employed two phototubes, changed over by a manual lever. The covers were two vacuum formings - rather like a suitcase.

Selling over 1000 units per year, the design carried forward into the PU8600 series and variants for many years.

The SP6 promotion was ‘Every lab should have one’.


The PU8600 added push button automation to the original SP6 series together with program and parameter storage in non-volatile memory.

1986 - PU8620 Series

The new PU8620 Series replaced the earlier PU8600 Series. It consisted of four models with the choice of a standard, factory-tested configuration or versions offering extensive kinetics facilities, optimised for life science applications.

All were available in VIS/NIR or UV/VIS/NIR options together with a vast range of accessories.

Instruments in the range featured a new Philips-designed diode detector and non-volatile method storage.

1988 - UV500

After the PU8-700 the next family of instruments developed was the UV Series - a traditional double beam design based on a stable, optical cast base plate.

It was available in either a Local Control version, or controlled by a PC and Vision software.

By now customers were requiring proof of analysis and data quality. A major sales thrust of the product was around the sophisticated self-test facilities built into the hardware and corresponding software facilities in the Vision software.

1993 - Helios Gamma

Many analyses required a band-pass of under 2nm and built in scanning capability. Thus the Helios range of spectrophotometers was designed.

These employed a concave diffraction grating and hence no collimator mirror. Virtually all the mechanical components were injection moulded plastic, including the optical base.

Over time variants aimed at specific industries were produced. Thus the Aquamate and the Biomate were launched.

The Vision software placed emphasis on aspects of traceability and security required by the pharmaceutical industry.

2002 - Evolution

The Evolution series of instruments was the last family of UV/Visible instruments to be developed in Cambridge (around 2002).

Certain components of the previous UV Series were becoming obsolete.

Life sciences was the target market. A small beam of light to pass through small cells, and a double beam instrument with wide beam separation to accommodate cell changers were necessary.

A major innovation was incorporation of a Xenon flash lamp as the light source.