How to choose the right spectrophotometer

December 2, 2023
Spectrophotometers are color measuring devices used to specify and communicate colors and monitor accuracy throughout the production process. Spectrophotometers measure almost anything, from liquids and plastics to paper, metals and fabrics. Brand owners, designers, laboratory technicians, and quality control professionals in almost all industries rely on these devices to ensure that color is consistent from specification to final quality inspection.
Choose the right spectrophotometer for your workflow.
Since desktop equipment is usually more expensive, many people wonder if the equipment investment is worth it. Today, we'll compare how portable and desktop colorimeters perform in common color measurement situations, so you can decide which one is best for your needs.
Overall comparison: desktop VS portable
Desktop devices are known to be more accurate and consistent than portable devices. Benchtop devices are often preferred when using strict tolerances or when formulating color specifications. Benchtop equipment is used for specification, formulation, and quality control by color professionals who must match the colors of a brand or its manufactured components at the time of final assembly. At the same time, the portable device is suitable for spot checking quality in the laboratory, or can be carried around to measure color anytime and anywhere for design inspiration.
Application comparison: How to use a desktop or portable spectrophotometer
1 -- Measure the transmission
If you want to measure liquids like orange juice, laundry detergent, or shampoo, desktop devices offer something that portable devices can't - transmission measurement. This is computed through the measured object. You can also measure the transparency and haze of plastic and packaging (such as 2-liter bottles and clear blister packaging) to ensure that the opacity is accurate.
2 -- Make the color paste
Desktop devices are the first choice for formulating color recipes. It is also widely used to prepare different degrees of opacity in plastics, to prepare liquid dyes for textiles and color pastes for paints.
3 - Set standards
Setting standards is a very important step in the color program. If you set the wrong color, how can you expect it to be accurate in production? When precise accuracy is required, benchtop instruments are often the first choice for setting color standards because they ensure repeatability and reproducibility of color accuracy.
4 - As part of a group of instruments
If you work with color management across regions, or use different instruments in your lab, you need to consider repeatability and consistency between each instrument. Even though measurements from the same instrument may vary slightly from case to case, the range of differences can be magnified when you're dealing with multiple instruments.
The benchtop instrument is designed to achieve accurate color repeatability, making the correlation between different devices higher. Although our portable devices are also excellent, there can be a 0.13 difference in portable devices at the high end of the market.
5 - Take it with you in the lab
Without a doubt, portable equipment is the best choice outside the laboratory. They are very useful for production spot checks to ensure color consistency throughout the run. It can also be used in the field to obtain color information used in the design or to perform quality checks at the supplier's site. Many devices provide Bluetooth connections that allow instant color analysis, while others plug into the main computer to download data.
6 - For quality control
While many people believe that portable spectrophotometers are suitable for quality control because of their portability, there are other things to consider.
First, measure the size of the point. In an ideal world, our 6 mm single point and 25 mm single point measurements would be identical. However, if the sample has small defects, such as tiny scratches, lint, dirt, or dust, this defect will occupy a large part of the small measurement area, returning erroneous measurements. Texture and orientation differences and sample imperfections also affect the results. Benchtop devices tend to measure larger areas and can average out defects better.
Second, the backing. Unless the sample is completely opaque, anything behind the sample at the time of measurement may reflect and alter the result. The desktop comes with a built-in backing, so it does not have to be considered. When using portable devices, the portability is excellent, but you also need to use a backing to get consistent results.
7 -- Measure fluorescent whitening agent
One final consideration: if you're dealing with fluorescent brighteners, you'll need to use UV-calibrated instruments for consistency. This is common for desktop devices, but some portable devices can also perform UV calibration.
So, which one do you choose?