Do you have a source for liquid Saybolt and ASTM D1500 Color Standards?

These liquid visual color standards can be used as an independent test to verify instrumental Saybolt and ASTM D1500 Color measurement performance over time for these two visual color scales used to evaluate oil, oil additive and petrochemical color quality.

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How do you measure the color of bare metal materials?

Bare Metal Brass Disks

Bare metal with a brightened, polished surface showing both color and gloss characteristics in the specular reflectance with a rapid fall-off to near black at the aspecular angles.

Bare metals are classified as opaque metals and do not allow any light to pass through them. In opaque metals, the specular reflection and diffuse reflection are key to defining the light interaction of this unique sample type. For bare metals both color and gloss are seen in the specular reflection which makes up a large portion of the reflection. Continue reading

When do I use Specular Exclusion in Color Measurement?

FAQ: ASTM D6290 recommends that I measure my plastic pellets for yellowness using the specular exclude mode. What is this?

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How is polarization minimized in HunterLab sphere instruments?

FAQ: “Do you sell a depolarizer for my HunterLab sphere instrument?  On occasion we test polarized samples and there is definitely a dependence on the orientation of the lens.  I was wondering if adding a depolarizer would eliminate this phenomenon?”

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What tolerance should be used for a PQ Performance Qualification on Transmission Color Measurements?

FAQ: “What is the limit on the standardization in TTRAN.  Using the small sample flask, filled with Ultra pure water. If they follow the protocol, they expect to find values (CieLab: 100.0; 0.0; 0.0)?” Continue reading

Do you have a source for Transparent Liquid Haze Standards?

HunterLab Distributor FAQ: “I have a new pharma customer doing color measurements.  They also want to do haze measurements and we had a discussion about haze standards.  Would our plastic haze standards be fine or is there a liquid haze standard out there?” Continue reading

What is a visual limit for Haze%?

FAQ: “What is a visual limit for Haze%? When should I be able to see a difference in a sample?”

A perfect clear of 0% would be air for transparent solids and the transmission cell of a defined path length filled with DI water for transparent liquids.

It should also be noted that the Haze% measurement of scatter in a sample is dependent on the thickness of transparent solid samples or cell path length of liquid samples.

The answer as to when you can see a visual difference will depend on the nature of the sample. For the plastic or glass sheets used in computer tablet screens, acceptable limits for what is faintly visible fall in the 1-2% range.

For pharmaceutical or chemical liquids, the average person may be able to see a visual difference in transmission haze at around 4 – 5%, and should definitely see a difference at a level of 6 – 7%.

To determine this for you sample, you should take a range of products exhibiting haze and get the consensus opinion of a number of people as to which samples show less than and more than visible sample. Measure Haze% using a sphere instrument and assign a visible limit specific to your product.

For many applications, especially those related to consumer products, a visible limit for haze is also the tolerance for acceptable product but not always…

Depending on the end use of the product, what is an acceptable may be below a visible limit if you don’t customer to see any visible haze difference in your product.

Or, if haze is inherent in the product and whatever is causing the product haze does not impact its use, an acceptable tolerance may be several times a visible difference. On these types of products, a typical range for good product might be from 10 to 12%, with an upper limit set at 20% just to ensure that any abnormal product is detected.

Air for transparent solids, or the cell filled with DI water or clear solvent for transparent liquids, is a physical product reference representing no haze, and the best your sample can be. A visible limit in product samples will typically be in the 2% to 5% range. What is acceptable in the marketplace will vary from less than a visible limit to some upper maximum.