In this article you will learn,
- Which parameters are set for typical measurement situations
- Some practical advice concerning measurement settings
1. Recommendations
Each measurement device offers a multitude of parameters, all of which are useful in their own right, but configuring and applying specific parameters can sometimes be a confusing and time consuming process. Users are often confronted with a multitude of choices when opening measurement device settings. Which settings make sense? In the following guide we will provide you with some fundamental tips concerning measurement device parameter settings.
1.1. Measurement Speed
The speed with which charts and specific patches can be measured is dependant on these factors
- The number of measurement patches
- The selected calibration mode
- The method of measurement
Number of measurement patches: The quality of the profile depends on the number of patches to be measured. The more values we have at our disposal initially, equals less interpolation of those measured values when calculating and creating a finished Profile. Based on the color management technology used – in our case ColorLogic – we recommend the following information:
Table 1: Overview of the number of patches to be used depending on the Colorspace and the measurement mode
| Mode | Colorspace | Number of patches |
|---|---|---|
| Linearization | CMYK | 30 – 90 |
| CMYK + 1 Gamut Expanding Color | 40 – 115 |
|
| CMYK + 2 Gamut Expanding Color |
48 – 138 |
|
| CMYK + 3 Gamut Expanding Color |
56 – 161 | |
| CMYK + 4 Gamut Expanding Color |
64 – 184 |
|
| CMYK + 5 Gamut Expanding Color |
72 – 207 |
|
| Profile | CMYK |
300 – 1800 |
| CMYK + 1 Gamut Expanding Color |
500 – 2300 |
|
| CMYK + 2 Gamut Expanding Color |
700 – 2800 |
|
| CMYK + 3 Gamut Expanding Color |
900 – 3300 |
|
| CMYK + 4 Gamut Expanding Color |
1100 – 4000 |
|
| CMYK + 5 Gamut Expanding Color |
1300 – 5000 |
|
| Reprofile* | CMYK |
100 |
| CMYK + 1 Gamut Expanding Color |
130 |
|
| CMYK + 2 Gamut Expanding Color |
180 |
|
| CMYK + 3 Gamut Expanding Color |
250 |
|
| CMYK + 4 Gamut Expanding Color |
300 |
|
| CMYK + 5 Gamut Expanding Color |
350 |
|
| * Reprofile with a profile update | ||
Calibration Mode: For the parameter Calibration Mode you can choose between Accuracy and Speed. The difference lies in whether the white balance for the measurement device should be carried out either once per measurement, per page or after every second line for the Spectro LFP or after every 4 lines for the x-Rite i1iO. It should be noted that controlling the white balance every second or fourth measurement line strongly affects the measurement speed.
Our recommendation: Always choose Speed, because generally speaking, the white balance of a measurement device does not often change in this sense.
Measurement Mode: The Measurement Mode for Spectro LFP, for example, means the measurement is either contactless, fast (with contact) or in an up-and-down movement. The setting you select here depends on the Substrate to be measured. Generally speaking, contactless measurement allows a lot of scattered light, therefore, direct measurement on the material is preferable. However, if the surface of the Substrate is too coarse, then the up and down Measure Mode is a good alternative.
Our recommendation: Choose with contact and depending on the Substrate choose Fast when possible.
Figure 1: The two setting dialogs for the Calibration Mode and Measure Mode
1.2. Measurement Condition
For measurement devices, different standards – M0, M1, M2 and M3 – can be used for the Measuring Condition parameter. Not all devices support all standards. You should therefore consider the following:
- If several different devices are used, you should choose the common denominator when setting the Measurement Condition parameter for all devices.
- In the best case scenario, only M1 should be used whenever possible. When purchasing a measurement device, also make sure that it has this parameter feature.
1.3. Illuminant
Measurement devices have different standards – A, C, D50, D55 and D65 – and can be used for the Illuminant parameter.
Recommendation: Depending on your current lighting conditions, the Illuminant parameter should be adjusted. Choosing D50, is generally a good starting point.
Illuminant to be selected for light boxes with fluorescent tubes
When fluorescent tubes or LED lamps are used in a light box, there is a difference in how the image is perceived. We recommend D50 for lightboxes with LED lamps and A for lightboxes with fluorescent tubes. These settings will typically compensate for any differences. Color adjustment of the image based on perceptive differences should be omitted.
1.4. Aperture
The device aperture defines the area that the measurement device reads while measuring. The larger the device aperture, the more accurate and consistent the results will be. Larger apertures offer the following advantages:
- A larger aperture covers a larger area and thus is able to perceive more information compared to a smaller aperture.
- A larger opening compensates for the scattered light that can occur on structured surfaces (Substrates)
- A larger opening compensates for the potential shadows of textured surfaces
Figure 2: The examples below show that if the device aperture is too small, the measurement results may not be representative or accurate.
Multiple measurements with an aperture that is too small coupled with the averaged measured values would certainly not improve the measurement result, as the case would be with a larger device aperture.
The disadvantage of using a larger device aperture is that the patches have to be printed out with a size that is approximately four millimeters larger than the maximum aperture used. Larger viewing angles also mean several pages need to be measured consecutively.
Recommendation: Even if the total measurement time increases due to the use of larger apertures, we recommend that you always use the maximum aperture size that your device can handle. This recommendation applies especially to Substrates with structured surfaces.
Measurement Devices with a fixed Aperture
Measuring devices available on the market are usually equipped with only one measuring port. The i1Pro 2 for example, offers an aperture measuring only 3.5mm, which is why this instrument is not the preferred choice when it comes to measuring highly structured Substrates. Other manufacturers, such as Barbieri Electronics, offer devices that are equipped with different apertures such as - 2, 6 or 8mm.
2. Measuring with Calibration Charts
A calibration chart has several patches and is usually distributed over several pages. Calibration charts are used for profiling in order to read specific values. Depending on the field of application, calibration charts can be measured either using reflected light – i.e. paper, cardboard, opaque foils etc. or transmitted light – i.e. glass, transparent foils etc.
Below we recommend settings which are used in combination with calibration charts. You can use the screenshots to compare our recommendations with your settings.
2.1. Barbieri Measurement Devices
The following recommendations apply to most of the Barbieri Electronics measurement devices. These are:
- Spectro LFP (Series 1, 2 and 3) – does not offer Measurement Condition M1
- Spectrol LFP qb (auto measurement) – only in conjunction with the measurement table
- Spectro Pad – offers only the 6 mm aperture
- Spectro Swing – does not offer Measurement Condition M1
2.1.1. Reflected Light Measurements
For reflected light measurements of calibration charts, the Device Mode parameter must be set to Page [1] and Measure Mode to Reflection [2].
Figure 3: A typical configuration for the Spectro LFP qb for the measurement of reflected light calibration charts
2.1.2. Transmission Light Measurements
For transmitted light measurements of calibration charts, the Device Mode parameter must be set to Page [3] and Measure Mode to Transmission [4].
Figure 4: A typical configuration of the Spectro LFP qb for measuring transmitted light calibration charts
Light boxes with fluorescent tubes or LEDs
Select the Illuminant parameter D50 for lightboxes with LED. For fluorescent lightboxes, select the A parameter.
2.2. X-Rite Measurement Devices
The following recommendations apply to most of the X-Rite measurement devices. These are:
- X-Rite i1iO with i1Pro1 – in combination with the automatic measurement table
- X-Rite i1iO with i1Pro2 – in combination with the automatic measurement table
- X-Rite i1Pro1 – in connection with the scanning ruler
- X-Rite i1Pro2 – in connection with the scanning ruler
2.2.1. Reflected Light Measurements
For reflected light measurements of calibration charts, the parameters Device Mode must be set to Page [5] and Measurement Mode to Reflection [6].
Figure 5: A typical configuration of the X-Rite i1Pro 2 for measurement of reflected light calibration charts.
Transmitted light measurement with X-Rite devices
X-Rite measurement devices are not capable of making transmitted light measurements.
Settings with or without a measuring table
The settings for measuring calibration charts should be the same for all four measuring instruments. The only difference between X-Rite i1Pro2 and X-Rite i1iO with i1Pro2 is that for the i1Pro2 there is only one measurement ruler and for the X-Rite i1iO with i1Pro2 there is only one measuring table.
2.3. Konica-Minolta Measurement Devices
The following recommendations apply to these Konica Minolta devices:
- Konica Minolta FD-9
2.3.1. Reflected Light Measurements
For reflected light measurements of calibration charts, the parameters Device Mode must be set to Page [7] and Measure Mode to Reflection [8].
Figure 6: A typical configuration of the Konica Minolta FD-9 for the measurement of reflected light calibration charts.
Transmitted light measurement for Konica Minolta devices
Konica Minolta measurement devices are not capable of making transmitted light measurements.
3. Spot Measurements
During daily production existing print samples need to be reproduced with the best color reproduction results. In practice, this is done by spectrally measuring samples, usually color patches, and using the resulting LAB values for the conversion. The measurement device must have the ability to make spot measurements.
Here you will find our recommendations that are used in practice to measure individual patches. You can use the screenshots to compare our recommendations with your settings.
3.1. Barbieri Measurement Devices
The following recommendations apply to these Barbieri Electronics devices:
- Spectrol LFP qb (spot measurement) – not used in conjunction with the measuring table; only via WIFI
- Spectro Pad – only has a 6 mm aperture
3.1.1. Reflected Light Measurements
For single reflected light measurements, the Device Mode parameter must be set to Spot [9] and the Measure Mode parameter must be set to Reflection [10].
Figure 7: A typical configuration for the Spectro LFP qb for spot measurements.
3.1.2. Transmission Light Measurements
Performing individual transmitted light measurements is not yet implemented for Barbieri devices.
3.2. X-Rite Measurement Devices
The following recommendations apply to these X-Rite devices:
- X-Rite i1Pro1 – not in combination with the measuring table i1iO
- X-Rite i1Pro2 – not in conjunction with the i1iO scanning ruler
3.2.1. Reflected Light Measurements
For single reflected light measurements, the Device Mode parameter must be set to Spot [11] and the Measure Mode parameter must be set to Reflection [12].
Figure 8: A typical configuration for the X-Rite i1Pro2 for spot measurements.
Dual point measurement
With the i1Pro2 you can also perform a dual-point measurement. Here your measurement is calculated with the measurement conditions M0, M1 and M2 all together.
3.3. Konica Minolta Measurement Devices
The following recommendations apply to these Konica Minolta devices:
- Konica Minolta CM2300d
3.3.1. Reflected Light Measurements
For reflected light patch measurements, the Device Mode parameter must be set to Spot [13] and the Measure Mode parameter must be set to Reflection [14].
Figure 9: A typical configuration for the Konica Minolta CM2300d for spot measurements.
4. Continuous measurement (Strip) of color values
In some situations, operators want to find out which color values occur in a pattern, for example. To achieve this, the measurement device must be moved along the pattern path, with the device performing permanent measurements. The measurements would result in a large number of different colors, which can then be reduced by the software to a defined number of the most common color values. Such measurement data can answer the question, "Which five color values occur most frequently in a specific pattern?
Here you can find our recommended settings that are used for strip measurements. You can use screenshots to compare our recommendations with your settings.
4.1. Barbieri Measurement Devices
The following recommendations apply to these Barbieri Electronics devices:
- Spectrol LFP qb (spot measurement) – not in conjunction with the measuring table; only via WIFI
- Spectro Pad – only has a 6 mm aperture
4.1.1. Reflected Light Measurements
For reflected light strip measurements, the parameters Device Mode must be set to Strip [15] and Measure Mode must be set to Reflection [16].
Figure 10: A typical configuration for the Spectro LFP qb when making a reflected light strip measurement.
4.1.2. Transmitted Light Measurements
The execution of transmitted light strip measurements is not implemented for Barbieri devices
4.2. X-Rite Measurement Devices
The following recommendations apply to these X-Rite devices:
- X-Rite i1Pro1 – not in combination with the measuring table i1iO
- X-Rite i1Pro2 – not in conjunction with the i1iO scanning ruler
4.2.1. Reflected Light Measurements
For reflected light strip measurements, the parameters Device Mode must be set to Strip [17] and Measure Mode must be set to Reflection [18].
Figure 11: A typical configuration for the X-Rite i1Pro2 when performing reflected light strip measurement.
