Macherey-Nagel NANOCOLOR UV/VIS II Manual Download Page 52

Page: 52 / 99

Color measurements

NANOCOLOR

VIS

II and

NANOCOLOR

VIS

II V 1.1 / 10.2017

ICUMSA sugar color according to ICUMSA

Method GS1/3-7

GS2/3-9

and

GS2/3-10

Beer color EBC (

Analysis Methods for Breweries Vol. 2

, EBC 9.4, MEBAK 2.16.2) and

ASBC.

Hess-Ives according to DGK test method F 050.2

The following colors indexes are calculated from CIE-L*a*b chromaticities:

Iodine color index according to

DIN 6162

Ph. EUR. coloring according to

Ph. Eur. 2.2.2

5.6.11

Differences compared to other colorimeters

To make things faster, most commercially available colorimeters measure only the
wavelength range from 360 nm to 780 nm, in some cases only to 720 nm, with an increment
of 10 nm. The

NANOCOLOR

spectrophotometers adhere to the strict recommendations of

the CIE. 360 nm to 830 nm, increment 1 nm. Therefore, slightly different values for L * a * b *
can be measured. These values are not incorrect, but rather, they are more accurate. The
following differences were observed on average: L* below 1% a* to 2% for red solutions,
otherwise below 1%, b* to 5% for green solutions, 2% for yellow solutions, otherwise around
1%. Differences depend on the type and concentration of the sample.

5.6.12

Measuring speed

The

NANOCOLOR

spectrophotometers are not simply colorimeters, but rather, full-fledged

spectrophotometers which can be used either as a colorimeter or for nephelometric turbidity
measurement. These instruments were not designed for speed, but rather, for precision and
versatility. Since the

NANOCOLOR

spectrophotometers make proper use of the CIE

recommendations,  the  measuring  takes  longer  than  with  other  colorimeters.  A  color
measurement  (ZERO  or  sample)  takes  about  30  seconds  at  an  integration  from  360  nm  to
830 nm.

5.6.13

Combinations of illuminants, observers and cuvette size

For an absolute color measurement, all cuvette sizes, illuminants and observers are allowed,
as long as the parameters are listed in the measurement log (see CIE publication).

Different

types of illuminants, observers or cuvette sizes will lead to different measurement
results!

Table 3 shows the allowable values for illuminant, observer and cuvette for each color index /
color scale. The cuvette size indicates the inner diameter ID and the layer thickness d. The
14 mm cuvette is the

NANOCOLOR

test tube; all the other cuvette sizes denote rectangular

cuvettes. The last column of the table "according to standard" means the layer thickness
specified by the relevant standard (see table 3). Some color indexes can be measured using
any cuvette size, even if the standard dictates a specific size. If a dash (-) is entered as the
standard size, then either the standard does not specify a size or the result is divided by the
film thickness in the calculation. If a dash (-) is entered in the

observer

illuminant

column,

the color index is calculated from the absorbance and not from chromaticity, so this setting is
not an issue.

For precise color measurements, the use of the 14 mm test tube is not recommended.

Color
measurement

Observer

Illuminant

Cuvette [mm ID/d]

Standard

[mm ID/d]

Standard color value