Laboratory Refractometer, Rudolph’s J457 with Smart Measure™ Technology Improves Results!

The J457 Electronic, Laboratory Refractometer is the most capable instrument in the Rudolph Research Refractometer Product Line. 3 models/configurations are available. All come with Rudolph’s exclusive Smart Measure™ Technology that virtually insures accurate Refractive Index (RI) and BRIX, measurements by automatically detecting sample problems. The J457 can determine when the prism is improperly cleaned, insufficient sample is loaded, or if the instrument is improperly calibrated. Various configurations are available for a small footprint, wall mount, or a remote-read factory configuration. All models come with a digital touch screen, and our Dual Temperature Control System utilizing Peltier Technology.

See the Rudolph Research J457 Laboratory Refractometer in action!

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The J457 Laboratory Refractometer, Simple to Operate Without Sacrificing Accuracy or Capabilities.

The Rudolph J457 can be configured with a Load and Go Measurement feature for your routine measurements tasks. Initiating a measurement begins by placing a sample on the prism. There are no buttons to press and all measurements are made  based on the per-determined Method. This allows the J457 to maintain it’s high level of accuracy and performance with Load and Go convenience.

Take a look to see how easily routine measurements can be made in the following video.

Versatile Data Storage Options

The J457 Refractometer offers various data storage options to meet the needs of any lab and any compliance requirement. With 32mb of on-board memory the J457 can work on a stand-alone basis or memory sticks can be utilized to expand memory or make data easily transportable to a PC. The J457 is easily connected to your network or may be linked with a PC. For all data storage options see: Refractometer Data Storage

The J457 Laboratory Refractometer with Smart Measure™ Advantage

Measurement problem:

> Sample residue is left on the refractometer prism surface

J457 Refractometer Sample Well

Experience has shown that incorrect laboratory refractometer measurements are often linked to cross contamination caused by the previous sample being inadvertently mixed with the current sample being measured. Ensuring that the prism surface is properly cleaned between measurements can be difficult for busy environments where multiple operators are involved. Rudolph Research Analytical has solved this problem as well as the related problems an inaccurate measurement can cause.

Smart Measure™ solution:

Automated clean prism monitoring is now integrated in the Rudolph Research J457 Laboratory Refractometer.

Smart Measure™ knows when the Refractometer’s prism is clean. If the prism surface does not produce the correct “Clean Prism” result then Smart Measure™ notifies the Laboratory Refractometer operator that further cleaning of the prism is necessary. Smart Measure™ notifies the operator that it is ready to measure after the prism is satisfactorily cleaned. The refractometer is now ready to make an accurate RI or BRIX reading with a verified clean sample well.

Measurement problem:

> An insufficient amount of sample covering the refractometer’s prism surface.

J457 Refractometer Sample Well

A small drop of sample in the center of the prism will measure correctly. A large drop of sample completely covering the prism surface will measure correctly. A small drop on the perimeter of the prism will produce erroneous RI and BRIX readings with the reason often unknown to the operator.

Smart Measure™ solution:

Automated sample load monitoring – reduces refractometer user error.

Smart Measure™ knows when a sample has been loaded on the refractometer‘s prism and immediately begins evaluating various metrics surrounding the sample load. If Smart Measure™ determines that those metrics indicate proper sample loading, it will display the result with a sample quality number. If Smart Measure™ determines that the metrics indicate an improper sample load, Smart Measure™ will ask the operator to clean the prism and re-load the sample.

Measurement problem:

> Sample contamination or improper refractometer calibration.

J457 Refractometer Sample Well

An improperly cleaned refractometer prism, where sample residue is left in the measurement well, can mix with a water zero or calibration fluid. This type of contamination during the refractometer calibration process will cause an error across all subsequent measurements, yielding incorrect RI and BRIX readings.

Smart Measure™ solution:

Automated sample calibration inspection.

Smart Measure™ is constantly measuring the refractometer’s prism surface and monitoring the value measured against its database of results. If during a water zero calibration the instrument detects a value that is too different from the database or the RI value being input is far from the measured value, it will alert the operator.

Measurement problem:

> The sample has air bubbles that affect measurement results.

J457 Refractometer Sample Well

Many samples have air trapped inside them or are carbonated. These samples read well most of the time as long as air bubbles are not trapped between the refractometer’s prism surface and the sample. When this happens the operator gets an erroneous result often referred to as a flyer. These results are called flyers because the measured value is quite different from the expected measurement value.

Smart Measure™ solution:

Automated sample calibration inspection.

Smart Measure™ catches these flyers by scanning the detector for varying RI values and then alerts the user to reload the sample. Since the user does not get a value to record until a new sample load is completed, Smart Measure™ greatly reduces the erroneous refractometer measurements from being recorded.

Smart Measure™ Features:

Smart Measure™ knows when to measure and display a result even when the operator does not.

Smart Measure™ Features – J457 Electronic Refractometers (all models).

  • Dirty prism detection
  • Incorrect calibration detection
  • Insufficient sample load detection
  • Cross contamination detection
  • Improper water zero detection
  • Trapped air bubble on prism surface detection
Laboratory Refractometer Sample Well, improper sample loading

Rudolph’s exclusive Electronic Dual Temperature Control System.

All J457 models come with Rudolph’s exclusive Dual Temperature Control System utilizing Peltier Technology. The J457 Refractometer heats and cools the sample from both prism surface and sample cover. The insulating cover housing seals the Prism Well Ring to create a uniform temperature environment providing unmatched temperature control uniformity resulting in consistently accurate RI measurements.

The Rudolph Research J457 line of Automatic Refractometers, come in three configurations to match your operating conditions and industry requirements.

J457-SC Automatic Refractometer in Standard Bench-top Configuration.

Laboratory Refractometer - Temperature Controled Automatic

J457-SC Refractometer in the Standard Configuration is Rudolph’s most popular configuration and provides an excellent combination of a small footprint and a large, easy-to-navigate digital touch screen interface.

J457-WC Automatic Refractometer in a Wall Mount Configuration.

J457-WC Refractometer in a compact Wall Mount Configuration is designed for production environments where water is used for cleaning or there is a lot of sample spillage on the work surface. This configuration is also excellent for situations where there is very little work space available: out on the factory floor or in an over crowded satellite laboratory where there is little to no remaining bench space for a standard Bench-top configuration.
Refractometer for Wall Mounting

J457-FC Automatic Refractometer in Factory Configuration.

J457-FC Refractometer in Factory Configuration is recommended when there is a lot of sample spillage on the laboratory’s instrumentation. Factories working with sticky resins and syrups that end up being spilled on the instrumentation are great candidates for the J457-FC as the measurement unit can be as much as six feet away from the display unit.

J457 Refractometer in a factory mounted configuration

Pharmacuetical Laboratory Refractometer J457 Rudolph Research

A Laboratory Refractometer for special measurement applications:

RI Measurement Kit for Solids, Semi-Solids, and Films.

Refractive Index measurement of solids and semi-solids is useful in laboratories for insuring the quality and consistency of transparency and pigmentation. Refractive Index is often measured on incoming materials and finished products. Highly accurate RI measurements are possible with the J457 Refractometer utilizing Rudolph’s Solid / Film measurement option and accessories kit.

Laboratory Refractometer Solid Film Kit

Return to view the entire Rudolph Research Product Line


All Rudolph Instruments carry our exclusive 20 Commitment to service your instrument.

Rudolph Research Analytical offers a comprehensive range of Preventive Maintenance and Service Programs. Rudolph has demonstrated a commitment to its customers by keeping installed instruments operational, not only for 20 years, but in some cases for over 40 years. This long-term commitment to keeping our instruments running makes the cost of ownership, over the life of a Rudolph Instrument, one of the lowest in the laboratory market segment. At the date this document was published, there is no other laboratory instrument manufacturer guaranteeing service and technical support for 20 years. View the entire 20 Service Guarantee. 


Laboratory Refractometer J457 – Specifications

J457 Automatic Refractometer Specifications (all models)
Measurement Scales

Refractive Index (nD)
BRIX (% sucrose)
and up to 100 custom programmed scales.

Measurement Range

Refractive Index 1.26 - 1.72,
BRIX 0 - 100%
Urine SG 1.0000-1.0400


Refractive Index ±0.00002,
BRIX ±0.015


Refractive Index ±0.00002,
BRIX ±0.015


Refractive Index ±0.00001
BRIX ±0.001

Temp. Control Range

10°C to 110°C
*other temperature control options are available

Temp. Control Reproducibility


Ambient Temp. Limit

5°C to 40°C

Temp. Correction Range

4°C to 95°C (for sucrose solutions)

Sample Temp. Limit

-20°C to 250°C

Optical Wavelength

589.3nm (NaD line)

Response Time

User configurable, generally less than 30 seconds


Using water or NIST traceable fluids. Factory default calibration can always be reset


Artificial Sapphire

Acid Resistance

Hastelloy™ measurement surface (optional)

Data Storage/Internal Memory

8GB non-removable Compact Flash


10.4 inch diagonal, 800x600 pixels, color, Flat Panel Monitor with Resistant Touch Screen Interface, 400 nits brightness, gasketted for spill protection.

User Interface


Communication Interface

3 USB, RS232 and Cat5 Network (Ethernet)

Operating Dimensions/Weight

L: 17 ¼”, W: 12”, H: 13” / 23 lbs.
L: 43.5 cm, 30.5 cm, 33 cm / 10.4 kg

Power Requirements

100 - 240 volts, 50 Hz - 60 Hz