Plastic pellets come in many different shapes, sizes, gloss, and translucency. In this study we compared the measurements of various pellets on three benchtop instruments.  The pellets were measured in HunterLab sample cup (HL# 04-7209-00).  The pellets were poured into the sample cup to to the top (50 mm height) to conform to ASTM D6290. Each sample was measured on the three instruments, and then poured and remeasured a total of 5 times.

The variety of pellets tested are shown below.

The results of the measurements are shown below

From this comparison, it can be shown that Agera provides the most precise measurements overall. This is due in part to the stability of LED illumination, advancement in optics, and larger viewed sample area. Along with the improvements in color measurement, Agera can also provide gloss information. The industrial touchscreen monitor and built in color measurement software on Agera eliminates the maintenance and workspace of an external PC that is required for similar operation of the LabScan XE and ColorFlex EZ. For optically brightened pellets, Agera also provides UV-Included and UV-Excluded control for automated comparative data viewing and reporting. 

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Color is an indication of quality and freshness of spices, that is why maintaining color accuracy and consistency in spices is important for appealing and responding to today’s customer’s needs. Therefore, special spectrophotometers with the right accessories and presentation techniques are essential to ensure uniformity and more repeatable results during measurement.
HunterLab in the past developed ColorFlex EZ as one of the standard instruments to measure the reflectance of spices. However, as spectrophotometric technology has advanced in recent years, and as our customers’ needs changes over time, HunterLab developed new innovative spectrophotometers that requires less sample prep and are designed specifically to move the sample under the sensor without touching the sample surface. This increases the measurement area of the sample.

Results of the study can be downloaded from the link below.

To begin the ASTM D1925 is a now obsolete Yellowness Index specification that is locked to calculate only using C/2 ( illuminant C, 2deg observer). When using ASTM D1925 the coefficients for Cx and Cy were 1.28 and 1.06, this goes back to the slide rule days of the 1940’s, when a colorimeter user would have to calculate YI using pencil and paper. These coefficients do not cause the equation to intercept exactly at zero for a perfectly clear specimen and instead give a value of 0.303.

ASTM E313 can be used to calculate Whiteness Index (WI) or Yellowness Index (YI) for C/2, C/10, D65/2, D65/10. If you specify ASTM E313 you must also specify YI or WI and an illuminant Observer combination.

Note that Yellowness Index is often used in the plastics industry to indicate that a clear plastic has no tint. In E313 C/2 the Cx and Cy were modified to 1.2769 and 1.0592, the extra precision fixed the intercept error so that a perfectly clear sample reports a YI= 0.0. So basically there is no bias between ASTM D1925 and E313 C/2 for your specification as long as there is some type of color to the sample.

The CIE (international commission on illumination) suggests that unless specifically instructed otherwise, always choose D65/10 for color comparisons and indices. This would imply that one should use YI E313 (D65/10) unless there is an need to use a difference illuminant.

Because the difference in the Cx and Cy is so small for C/2 there is almost no difference between the indices when the sample has a large amount of yellow, as can be seen in the example below. Using D65/10 will cause differences.

ID YI D1925 [C/2] YI E313 [C/2] YI E313 [D65/10]

PIF090-84 17.18 17.18 17.66

Let me know if you have further questions.

Posted on June 2, 2015 by Gordon

Carbon black, also called charcoal black lamp black, pigment black, soot or black carbon, is a fine particle carbon pigment obtained as soot from the incomplete combustion of many different types of organic materials, such as natural gas, or oil. Carbon black is usually a fine, soft, black powder. It is very stable and unaffected by light, acids and alkalis. It is commonly used in printing and lithograph inks and in Chinese ink sticks. In industry, carbon black is used as a filtration material and a filler /pigment in coatings, rubber, plastics, paints, carbon paper, and crayons.

Some synonyms for carbon black pigment —- Channel black; lampblack; Pigment Black 6 and 7; CI 77266; gas black; diamond black; smoke black; soot black; flame black; furnace black; acetylene black; thermal black; graphite; charcoal black; coal black; bone black; vine black; sumi (Jap.); hiilimusta (Fin.); nero di carbone (It.); noir de carbone (Fr.).” Source: Dandong MB Carbon Black Pigment Co., Ltd, Chinawww.mbssth.com

For how black is black, there are 3 metrics used to quantify the color quality of black created in a coating, plastic and rubber substrates.

Blackness My is a measure of the degree of blackness, directly related to the reflectance. Typical reflectance values are typically below 5% and can be below 1% for the best blacks. The bottom-of-scale standardization of the instrument sets a measured reference for 0%.

Blackness My = 100*log (Yn/Y)

Jetness Mc is the color dependent black value developed by K. Lippok-Lohmer. As the Mc value increases, the jetness of the masstone increases. Sample preparation is typically based on an opaque drawdown of a black masstone based on black pigment and binder.

Jetness Mc = 100*[ log(Xn/X) – log(Zn/Z) + log(Yn/Y) ]

• Test sample is typically measured with a directional 45/0 instrument geometry
• Xn = 94.811, Yn = 100.000, Zn = 107.304 are the CIE White Point values for D65/10 conditions
• X, Y, Z are the CIE tristimulus values for the sample being measured

Undertone dM quantifies how neutral the black pigment + binder is. As Mc = dM + My,

Undertone dM = Mc – My

• If dM < 0, the undertone is brown-reddish
• A dM value = 0 would suggest the black is perfectly achromatic or neutral
• If dM > 0, then the black exhibits a bluish undertone which is often preferred

Industrial References for Blackness [My], Jetness [Mc] and Undertone [dM]

European Coatings Handbook – Thomas Brock, Michael Groteklaes, Peter Mischke, Vincentz Network GmbH & Co KG, 2000 has a good overview of black pigments and blackness measurement.

Lippok-Lohmer, Farbe+Lack, 92, p. 1024 (1986) describs both Jetness [Mc] and Undertone [dM].

DIN 53235 Testing of pigments – Tests on specimens having standard depth of shade describe Jetness [Mc].

DIN 55979 Testing of pigments – Determination of the black value of carbon black pigments describe Blackness [My].

Carbon Black Tint Strength [T]

As referenced in ASTM D3265, Carbon Black Tint is a measurement of reflectivity for calculation of tint strength as:

Carbon Black Tint Strength [T] = (I/S) x 100

where:  S = Y C/2 reflectance reading of sample

I = Y C/2 reflectance reading of ASTM Tint Reference Carbon Black

• I and S correction coefficients are determined empirically per ASTM D3265.
• The carbon black sample is let down in a standard ASTM Tint Zinc Oxide White base.
• The industry tint reference carbon black and zinc oxide white are available from ASTM www.astm.org .

Industrial References for Carbon Black Tint Strength [T]

ASTM D3265 Carbon Black – Tint Strength

A carbon black sample is mixed with a white powder (zinc oxide) and a liquid vehicle (soybean oil epoxide) to produce a black or gray paste. This paste is then spread to produce a surface suitable for measuring the reflectance of the mixture by means of a photo-electric reflectance meter. The reflectance of the tested sample is then compared to the reflectance of the ITRB prepared in the same manner. The tint strength of the tested sample is expressed as units of the reflectance of the ITRB divided by the reflectance of the sample and multiplied by 100.” ASTM www.astm.org

Posted on June 7, 2016 by Gordon

ASBC Color

The ASBC Beer Color scale has a range of approximately 1 to 11 units, with the more yellow, pale worts at the low end of the scale and the redder color of dark worts, beers and caramels at the upper end of the scale.

The industry reference method for ASBC Beer Color and Turbidity Is:

ASBC Beer-10 Color of Beer Part A. Spectrophotometric Color Method available from ASBC – American Society of Brewing Chemists, affiliated with AACC – American Association of Cereal Chemists, St. Paul, MN USA www.scisoc.org/aacc.

The ASBC Color metric is based on a simple spectral absorbance (A) measurement at 430 nm of decarbonated beer using a 0.5-inch path length cell. The formula was originally defined as:

ASBC Beer Color = 10*(A½), 430 nm

In allow ASBC Beer Color to be measured and reported simultaneously using the same 10 mm cell path length cell that used to measure EBC Beer Color, a conversion factor of 1.27 is used to scale absorbance measured using a 10 mm path length cell to absorbance the original 0.5 inch path length cell.

A½, 430 nm = 1.27*A10mm@430nm

The resultant ASBC Color formula when the sample is measured in a 10 mm path length cell becomes:

ASBC Beer Color = 10*1.27*A10mm@430nm

The instrument is typically standardized or blanked to 100% transmittance (absorbance = 2) on the cell filled with distilled water.

ASBC Turbidity

ASBC Turbidity is based on a simple spectral method that measures absorbance at two points – one in the blue (430-nm) and one in the red region (700-nm).

For the same reason that the sky is blue, scattering or turbidity in a liquid can be measured if the blue spectral absorbance is significantly different from the red absorbance.

If the absorbance is significantly different at these two points, then the ASBC Turbidity of decarbonated beer or similar liquid sample is rated as being “turbid”; if not then the rating is “free of turbidity”.

The test assumes the beer or wort solution has been decarbonated following guidelines in the ASBC Beer-10 Color of Beer method, and that any turbidity is caused by undissolved solids not removed by filtering.

For ASBC Turbidity, if the Absorbance at 700-nm <= 0.039*Absorbance at 430-nm, the beer is rated “free” of turbidity”; otherwise the rating is “turbid” is reported, indicating some visual scattering in the sample.

Example Calculation of of ASBC Beer Color and ASBC Turbidity

Following ASBC Beer-10 Color of Beer standardize sphere instrument in TTRAN mode using 10 mm path length cell filled with distilled water as top-of-scale standard.

The internal absorbance of liquid beer sample measured in 10 mm path length transmission cell was determined to be 0.31 at 430 nm and 0.01 at 700 nm.

• Conversion factor for transmission cell path length conversion from 10 mm to 0.5 inch = 1.27
• Absorbance of beer at 430 nm (A430nm) using 10 mm path length cell = 1.27*0.31 = 0.394
• Absorbance of beer at 700 nm using 10 mm path length cell = 1.27*0.01 = 0.0127

ASBC Beer Color = 10 * 0.394 = 3.94 = 3.9°

ASBC Beer color is calculated to at least 2 decimal places and rounded to 1 decimal place for display in units of degrees (°). The higher the ASBC Beer Color value; the lighter the beer. Consistency from lot-to-lot of the same beer type would also be important.

In terms of ASBC Turbidity, as A700nm of 0.0127 is less than 0.039*(A430nm = 0.394) = 0.0154, this beer sample is rated as “free of turbidity”.

Advantages and Disadvantages of ASBC Color and Turbidity

Both of these metrics use objective quantification as a basis which is more consistent than visual evaluation of color and scattering in these liquids samples. However, for ASBC Turbidity, the reported values are either “turbid” or “free of turbidity”. These are acceptable for product specification but not as effective for characterizing lot-to-lot consistency in production. For this situation, either ASTM D1003 Transmittance Haze or NTU Turbidity measurement would be preferred, as they report product scattering in a quantifiable scale based on instrumental measurement.

The situation regarding ASBC or equivalent EBC Color is similar. While based on spectral measurement and useful for reporting for product specification, the CIE colorimetric scales offer a complete quantification of product color. If the product is consistent in CIE L*, a*, b* D65/10 measurement, it will be consistent in the singular ASBC or EBC Color.

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Question: If customer uses UltraScan PRO, UltraScan VIS or VISTA to measure the sample’s APHA . 

After Standardization (use the 20mm cell fill with the Purified water) to measure the same water with APHA20mm.  What is the correct value to indicate the standardization was successful?

Answer:

APHA is only valid when the average result from three consecutive readings is reported. HunterLab uses a third power polynomial of the YI E313 C/2 reading to calculate APHA. 

For UltraScan Vis and UltraScan Pro, the Instrument Repeatability is stated to be dE* <0.03.

The act of standardizing the instrument creates the following TOS L*=100.00 a*=0.00 b*=.00

If the average of the next three reading produces a L*=100.00 a*=0.00 b*=0.03 the dE* from standardization passes our repeatability specification and the calculated APHA 20mm would be 0.31 This implies the maximum APHA after standardization would have to be <0.3></0.3>.

A better way to state this is that the Standardization check for APHA is 0.0 +/- 0.3, meaning that any value between -0.3 and 0.3 should be reported as 0.0 since the operator cannot distinguish between those values due the uncertainty created by the instrument repeatability.

For VISTA the Instrument Repeatability is stated to be dE* <0.025></0.025>. The act of standardizing the instrument creates the following TOS L*=100.00 a*=0.00 b*=.00.  If the average of the next three reading produces a L*=100.00 a*=0.00 b*=0.025 the dE* from standardization passes our repeatability specification, the calculated APHA 20mm would be 0.26. This implies the maximum APHA after standardization would have to be <0.26></0.26>.

A better way to state this is that the Standardization check for APHA is 0.0 +/- 0.26, meaning that any value between -0.26 and 0.26 should be reported as 0.0 since the operator cannot distinguish between those values due the uncertainty created by the instrument repeatability.

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In theory if the same cell is used and the solvent is the same for the Blank and the Sample solution then the L* for nearly colorless liquid should not be greater than the repeatability range of the instrument. Note, this also assumes no UV or Visible activated fluorescence or bioluminesce is occurring.

If the cell used to Blank is not the cell used to measure the sample then the user should experiment to determine if the cell is the cause of the difference. To do this you can standardize on Air, then measure a group of empty cells first, then cells filled with the same solvent and examine the range of readings.

Quartz cells are typically only required when wavelengths in the range of 190nm to 350nm will be measured. For HunterLab instruments Glass cells are sufficient for use, and plastic (PMMA) can be used if the user conducts a risk analysis as plastic cells typically have greater spectral variance than glass cells.

If the solvent for the blank is not the same as the solvent for the sample then this becomes a physics/chemistry question where refractive index, molecular composition, etc. can affect the readings.

For example it has been seen that when blanked on water, reading methanol based solutions L* values of 102 to 104 are common. Other organic solvents produce similar results relative to water blank. Normally most procedures specify which solvent to use when standardizing the instrument. Never assume that one should always use water as a blank, especially if the sample solution does not contain at least 50% or more water.

Question : Does the L*a*b* value influence the Haze reading, for example do darker colors (low L*) also have lower Haze than lighter colors ( high L*) or is this an over simplification.

Answer:

%Haze is a physical attribute that is unrelated to the color of the specimen being measured. When light is collimated at 90 degrees through a transparent object it can either be transmitted through the object without changing angle, or it can scattered at angles other the incident angle. %Haze is equal to 100 times the quotient of the scattered light divided by the sum of the scattered light and incident transmitted light.

Imagine reading a newspaper through a pair of eyeglasses have nearly perfectly clear lenses. These lenses if measured would have an L* in the 92 to 95 range and a % haze value close to zero. Now consider if you had to read the paper by looking through a polyethylene sandwich bag. The sandwich bag probably has an L* close to 90 but with a %Haze in the 20% to 30 %Haze range or higher. Still clear enough to read but the type and photos would appear slightly fuzzy. Now put on a pair of dark green sunglasses. L* in the 30 range, %Haze close to zero. That type and photos would take on a green hue due to the lens color but would appear as sharp as when you were wearing the clear lenses.

Question:

I was asked during a recent audit to provide a calibration and traceability certificates for the black glass I use to calibrate my 45:0 instrument. I said that none were provided when I purchased the instrument. Why were they not provided?

Answer:

We follow the ASTM E1164 Standard Practice for Obtaining Spectrophotometric Data for Object Color Evaluation. The full text of ASTM E1164 is available for purchase from the www.ASTM.org

Referring to section 10.2.1 which states that the Full Scale Standardization shall be done using a White Reference Standard calibrated relative to the perfect Reflecting diffuser. This implies that the White Instrument Standard has unique calibrated values which would need to be substantiated by a Calibration and Traceability statement.

Referring to section 10.2.2.1 for 0:45 and 45:0 Zero Scale Standardization shall be done with "a highly polished black glass standard with an assigned reflectance factor of zero." This implies that for any highly polished black glass the reflectance factor is zero at all measured wavelengths. There is no calibration required to assign the reflectance factor at each wavelength. The reason why no calibration is required is that except for a few very expensive instruments maintained by the NMI's of the world the true reflectance of polished black glass is many magnitudes below a commercial instruments ability to measure it.

Question: We recently purchased a set of calibrated tiles and would like to know the expected inter-instrument agreement between all of the HunterLab sensors our company uses to measure the color of our product.

Answer:

The most widely accepted method of using CCSII tiles (Lucideon/Ceram/BCRA 12 Glossy tiles) is to create a target for each color from the mean of the population readings of the sensors in your company. Then periodically read the tiles and record the color difference (dE* or CMC or dE2000) for each tile from its target value. Then calculate the average of the 12 color differences. If the average is less than 0.15 then the instrument is considered acceptable for use. You may also wish to bound the set with a maximum allowable color difference (e.g. no individual color difference greater than 0.30).

There are many other ways that these tiles are used, such as separating the performance reading the 4 gray tiles from the performance reading the colored tiles or calculating the recording the color differences between reading the Gray and Difference Grey and Green and Difference Green tiles.

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Question: What is the difference between Lycopene versus Fresh Tomato Color Index (FTCI)

 Answer: Lycopene Index and Fresh Tomato Color Index are very different and have specific uses.

Fresh Tomato Color Index is fixed for all users.

Fresh Tomato Color Index FTCI = (100((21.6/L) - (7.5*b/(L*a))) using the Hunter L, a, b color scale for C/2 conditions. 

There is no universal "Lycopene Index". While there are correlations cited in literature, they are all dependent on the method of sample preparation and measurement which varies from publication to publication. Effectively each user establishes their own "Lycopene Index".

CMR3098 offers the following equation for the calculation of Lycopene Index.

Lycopene Index (mg/kg) = (a/b – Offset)/Gain

where,  gain is user-editable = 0.0039 as default

 offset is user-editable = 0.3319 as default

 a/b ratio is determined from Hunter a and b color values, fixed for C/2 conditions.

The user is expected to determine their own gain and offset if they want to more closely HLPC or spectrophotometric transmittance measurements.

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FAQ: " I have a customer who wants to measure something called 'Neat Color' at a temperature of 150°C.

They have seen that in the US, a company is doing this using a Hunterlab instrument with “SpecWare Version 1.10 + Brass sample holder with slots 10 mm apart for glass slides and microscope slides, 3x2” glass”

Do you have any idea which instrument this is?"

To the best of my knowledge, there is no color scale called "neat".

Instead what I think it refers to is measuring the color of the material neat, meaning undiluted. More than likely this is some type of chemical concentrate (often crystals or pellets) that has to be heated undiluted to 150 C to make it into a liquid where the color, typically APHA/Pt-Co or Gardner, is measured as an indication of color quality.

Here is a note on how we generally approach hot liquids - Measuring Hot Liquid Samples - AN 1030.00

Specware was HunterLab's legacy DOS color software. The brass device sounds like a custom sample holder.

If you can find out any more information, we can better advise.

Device-Selective-Suspended is added as an option for USB-Serial adapter in Win11. 

If you see the following error in EZMQC for UltraScan Pro or UltraScan Vis when EZMQC idle for a while and have to reconnect sensor or restart EZMQC to reestablish the connection, the device-selective-suspended might be enabled in your windows.

Please follow the instructions below to disable device-selective-suspended.

• Make sure that the usb-serial adapter and the serial cable are connected correctly between PC and the instrument.
•  Go to PC Control Panel/Device Manager, check Ports(Com&LPT), and find the com port number of this usb-serial adapter. E.g. The example in pic below is com4.

• In Windows search box, search and open ‘Registry Editor’, go to Computer\HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Enum\USB. Right click on USB and click Find. Search for the com port number of this USB-Serial adapter that you find in device manager above.
• 

• In the right view aera of Registry Editor, you will see all the options listed for the USB-Serial adapter. When the value is set to 1, it means that selective suspension of USB devices is enabled, allowing Windows to selectively suspend the operation of certain USB devices to conserve power when they're not actively in use. When the value is set to 0, it means that selective suspension of USB devices is disabled, and Windows will not selectively suspend USB devices.

After applying this change in registry edit, the USB-serial adapter should work correctly to keep EZMQC and the instrument connected.

The Gardner Scale was originally defined by the colors of a series of 18 Glass Standards that began with a light yellow and ended with a deep brown. This scale can also be reproduced using solutions of Potassium Chloroplatinate, Ferris Chloride and Cobalt Chloride.

The intent is a linear progression, light to dark, of the color of oils and varnishes for colors 1-8. Colors 9-18 is a linear progression of deeper yellow-browns to simulate oils and varnishes that had been heated. ASTM D6166 publishes a standard set of Yxy co-ordinates for the Glass Standards,. When plotted, colors 1-8 show a linear progression in Y and xy and 9-18 show a different linear relationship. The two groups if plotted together show a shift in slope between color 8 and 9.

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What is the best way to measure the effects of UV optical brighteners in our samples with our HunterLab instrument?

The recommended method is a two-part measurement sequence. The first measurement mode you will need to setup is the UVF Calibrated (UV included) mode. This mode will provide some UV content but will provide a consistent amount of UV content. The second mode you will need to setup is the UVF In (UV Excluded) mode. This mode will effectively exclude all UV content of the lamp.

After you take your two measurements in UVF Calibrated and UVF In you will then need to compare the significant indices you are concerned with for your product. For some customers this might be a L* value, a b* value, or maybe a WI index; this will be personal and depend on what your facility has established as a meaningful metric.

It is important that the UVF Calibrated mode is used because UV content in a lamp will vary from instrument to instrument and is affected by several factors. By using UVF Calibrated you are using a consistent UV content that will stay consistent as the lamp in your instrument ages. These settings could also be applied to different instruments should you upgrade down the line.

Repeatability test tells us the condition of the lamp flash system and electronics independent of color accuracy. Didymium filter test tells us the wavelength accuracy of the instrument independent of reflectance color accuracy. When taking a measurement the integrating sphere interior wall mixes and homogenizes the light reflected from the sample. The wall coating is a critical part of the process, as much as the wavelength alignment and repeatability of the measurement process. the Green tile is a single color in the middle of the wavelength range and middle of the linearity range. It does a good job of predicting the general color accuracy performance of the instrument. The full Color Tile readings are done when the first two tests are successful and provides a "stress test" of color accuracy by using tiles that represent a fairly complete non-chromatic and chromatic color range. The tiles Red, Orange and Yellow have the lowest reflectance in the range from 360 to 600nm of all of the tiles in the set. Dirty lenses causing diffusion can affect the low reflectance readings as can sphere wall dulling, or aging.

EP 2.2.1 Defines three instrumental methods

1. Nephelometry - View the specimen at right angles ( 90 degrees ) to the direction of incident light. Use for NTU values less than 1750 to 2000 units.

2. Turbidimetry - A property of the specimen's ability to scatter or absorb light as opposed to transmitting it in a straight line through the sample.

3. Ratio Turbidimetry - ratio of the transmittance measurement to the 90 degree measurement

HunterLab does not offer 90 degree detection, so technically we only fully conform to a Turbidimetry measurement, but EP 2.2.1 says "Instruments with range or resolution, accuracy and repeatability capabilities other than those mentioned above may be used provided they are sufficiently validated and are capable for the intended use." So any instrument may be used as long as it is validated.

There are some samples that can only be correctly measured using Nephelometry, but HunterLab has been able to show valid correlations to Opalescence and lower NTU units when creating calibration curves using our benchtop transmittance capable instruments.

See an05_07 for a method to validate HunterLab instruments.

[Opalescence - an05_07](https://support.hunterlab.com/hc/en-us/articles/203995865-Opalescence-an05-07)

Question:

ISO 17025 accredited lab and would like to know if there is any type of annual calibration that would be needed to maintain this equipment.?

Answer:

The calibrated specimen supplied with the sensor is the White Instrumetn Tile. This was supplied with Certificate of Traceability showing both the calibrated values and the uncertainty of the calibration ( for all expect LSXE and CQXE ). An expiration date is not shown on this certificate, individual users typically choose a timeframe of between 12 and 60 months to have this tile recalibrated.

Color Measurement is a unique field in metrology since there are no intrinsic standards of color expect for White. To compensate for the lack of intrinsic color standards the industry has standardized on using Lucideon CCSII tiles as consensus standards of color. Since color measurement is device dependent HunterLab has created targets based on the mean of group of known good sensors and uses these values to validate the color measurement performance of an instrument that was standardized using a calibrated Instrument Standard White. If the instrument can read back these CCSII tiles to within the stated uncertainty for the tile and tile set then it is implied that the instrument falls within the population mean of the instrument family.

Your sensor was shipped with a copy of its factory verification. We recommend that you have this type of verification performed at not more than 15 month intervals.

 Following the best practice procedures for cleaning your HunterLab instrument is important in order to avoid damage and to ensure proper hygiene between users.

We recommend using the stylus pen that is included in the standards box for instruments that include touch screens. You may order additional stylus pens directly from HunterLab (part number A13-1017-504), or you may obtain your own.

What you will need:

• Non-Abrasive Lint free paper towels
• 60-70 % isopropyl alcohol. DO NOT USE ALCOHOL GREATER THAN 70%
• Alternatively, single use alcohol based sanitary wipes can be used. DO NOT USE BLEACH or ALCOHOL GEL products to avoid damaging the touchscreen.

 Cleaning Instructions

• Wash your hands with water and soap for 20 seconds, and then dry with a towel. Wear a face mask and protective gloves to prevent contamination.
• Save and close all open jobs that you wish to retain and then power off the instrument
• Dampen a paper towel with the isopropyl alcohol. Wring out any excess liquid to avoid getting liquid inside the sensor.
• Wipe down the outside of the sensor case.
• Repeat the alcohol cleaning of the touch screen (if applicable) and stylus pens with a new towel.
• Repeat the alcohol cleaning of any other accessories that were used since the last cleaning cycle. 
• Dispose of all towels or wipes in the proper waste container.
• When cleaning the standards, follow the specific instructions in the user manual for that instrument.  Follow these instructions.
• See the special tile cleaning instructions for Instruments that use PermaFlect white tiles. https://support.hunterlab.com/hc/en-us/articles/360032430251-Cleaning-Instructions-for-White-Standard-Tile-for-Agera-Aeros-SpectraTrend-HT

A video demonstration of the procedure is available at the following link:

https://youtu.be/fID1e1URtys

Do you still need more information? Submit a ticket and our support team member will reach out to you soon!

Question: How to interpret Haze Tolerance?  e.g. Performance +/- 0.30% @ 10% TH

Answer: Most indices such as APHA, EP Color, Gardner, Saybolt, NTU and USP are based physical standards. A Haze measurement is determined by the instrument geometry being exact, not by how it reads a physical standard. There is no formula for how to create a Haze Standard with a value equal to 10. The user guesses at what will produce a value close to 10 then measures it on an instrument that meets the exact geometry and measurement conditions for Haze and records the result.  Typically a 10% Haze Standard will have an assigned value between 8.5 and 11 %TH. The tolerance for a Haze Std is +/- 10% of its assigned value. For example if the standard is assigned at 8.5 %TH then the tolerance is 8.5 +/- 0.85 %TH, for 11 %TH the tolerance is +/- 1.1 and so on for any Haze Standards in the 10 %TH range.

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Below is a link to our rental request form when having your instrument serviced. Before coordinating a rental instrument your instrument will need a Service Return Order (SRO) number assigned.

Question: Can HunterLab transmittance instruments measure Haze and Clarity?

IMPORTANT NOTE:

While the term "clarity" is a common noun that refers to the transparency or purity of a substance it has two very different Colorimetric meanings depending on Industry of use.  Two answers will be provided, one for the measurement of transparent plastics and one for the measurement of pharmaceutical liquids.

Answer for Transparent Plastics:

Haze equals the percentage of regular rays that are diffracted greater than 2.5 degrees from normal.  This is sometimes called Wide angle scattering and this measurement is defined by ASTM D1003.

Clarity equals the percentage of regular rays that are diffracted at an angle of less than 2.5 degrees from normal.   This is sometimes called Narrow angle scattering.  This measurement can only be done using a Hazemeter that is configured either specifically for a Clarity reading, or once that that dual detectors to simultaneously collect both Wide and Narrow angle scattering.  

The Vista can measure both the color and the %Haze of a specimen, it can not measure the Clarity. A Hazemeter can measure both the %Haze and Clarity of a specimen, it can not measure the Color.

Answer for Pharmaceutical Liquids:

EP2.2.1 The Clarity and Degree of Opalescence of Liquids, states "A liquid is considered clear if its clarity is the same as that of water R or of the solvent used when examined under the conditions described above, or if its Opalescence is not more pronounced than that of reference suspension I 

HunterLab transmission instruments can be used to measure the color and clarity and opalescence of Pharmaceutical liquids.

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Question:  Is dE the Standard Deviation between Sample and Standard?

Answer:

A bare bones description might be;  dE is color difference from a Standard and when a tolerance is applied, it is presumed than any dE value less than the tolerance will be an acceptable match.  CIE76, which is the technical description for dE*, is the geometric distance in color space between the Standard and Sample reading.   Since human perception is not uniform throughout the gamut of color space it is recommended that each Standard Color have a unique acceptance tolerance associated with it when using dE*.    For example our ability to differentiate between different shades of Yellow is much greater than our ability to differentiate between shades of Deep Blue.  If a tolerance dE* < 1 indicates an acceptable match for the Yellows, to have a visually comparable tolerance for Deep Blue might result in a dE* < 1.7   

CMC (dECMC) and CIE2000 (dE*2000) consist of complex equations such that a uniform tolerance can be applied throughout color space.   These equations were designed so that a value of 1 represents the limit of an typical acceptable match.   Using CMC or CIE2000 would allow the user to apply a tolerance of 1 to both the Yellow and Deep Blue colors from the previous example.     

Standard Deviation, and k or C.I. (confidence interval),  are statistical terms that are used to model univariate groups of data that follow a Gaussian distribution.   These models work well when applied to XYZ or  Indices, but may be flawed when applied to multi-variate values like the different dE types.  Since dE can't be negative it's impossible to get a normal distribution, which is what Std. Dev. is designed to represent.   When using a group of dE's a Hotelling model t2 should be used.