Spectrophotometer wroking procedur

Md. Moktadidul Hoque (Murad)
B.Sc. Engineer (Textile)
1
Introduction
A Spectrophotometer is one of the scientific instruments commonly found in many research
and industry laboratories. A spectrophotometer is capable of both transmitting and receiving
light. The device is used to analyze samples of test material by passing light through the
sample and reading the intensity of the wave lengths. Different samples impact the light in
different ways, allowing a researcher or technician to learn more about the materials in the
test sample by seeing how the light behaves as it passes through the sample.
The output of a spectrophotometer is usually a graph of light intensity versus wavelength.
The data collected to generate this graph can typically be saved as a table of wavelengths and
intensities.
Functions of Spectrometer:
Spectrometer is used for various purposes in wet processing industry. Such as:
1. To match the color of swatch produced in lab with the swatch provided by the buyer.
2. To determine the whiteness value or darkness value of the sample.
3. Recipe calculation for a given color is possible.
4. Numerical data can be determined of sample color.
5. It is possible to produce a target color by the combination of different color.
6. Pass or fail report can be determined for particular sample and the report can be
printed.
7. We can get the amount of different color present in the shade both as percent and as
graph value.
8. Color exhaustion graph for specific brand color can be found.
9. All the information can be saved in the computer.

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Brand Name:
 X-Rite (www.xrite.com)
 Macbeth
 Datacolor (www.datacolor.com)
 Minolta
 Treepoint
Datacolor:
Datacolor is a global leader in color management solutions and color communication
technology. The world’s leading brands, manufacturers, creative professionals and consumers
have been choosing Datacolor’s innovative technology and solutions to consistently achieve
the right color for nearly 40 years.
Software that need to run datacolor:
To run data color the following software’s are needed to be installed:
 Datacolor Tools (DCI-Tools)
 Datacolor Match (DCI-Match)
Datacolor Tools have following functions:
 Input of standard: It may have physical standard such as swatch, TC, PC, TCX, PCX
& numerical standard such as Qtex file.
 Pass fail report, Fastness properties, color change etc.
Datacolor Match have the following functions:
 Recipe calculation such as it gives main recipe, corrected recipe, costing & also
metamerism index.

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Calibration of Datacolor:
Calibration is a process in which a scientific instrument known as a spectrophotometer is
calibrated to confirm that it is working properly. This is important, as it ensures that the
measurements obtained with the instrument are accurate. The procedure varies slightly for
different instrument, with most manufacturers providing a detailed calibration guide in the
owner’s manual so that people know how to calibrate the equipment properly. When this
process is performed, the person doing it must make a note in the log attached to the
equipment and in their experimental notes, so that people know when the device was last
calibrated and handled, and by whom.
The following calibration procedure is generally followed-
 Click the Calibrate button on the button bar, or Instrument Menu, Calibrate.
The current calibration conditions are displayed:
 Click Calibrate. The Prepare for Calibration dialog box displays.

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 Place the black trap over the measurement port, and click the Ready button. If the
instrument does not have a black trap, clear the port of any obstruction and click the
Ready button. The Prepare for Calibration window redisplays when the measurement
is completed.
 Place the white calibration tile over the measurement port, and click the Ready button.
When the second measurement is completed, the Control Measurement dialog box
displays.
 Click OK. If you have the diagnostic (green) tile test enabled, the program will
prompt you for the diagnostic tile.

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 Place the green tile at the port and click Ready. When the measurement is complete,
the results of the diagnostic tile test will be displayed.
 The DECISION should be "Pass". Click OK to close the instrument.
Measurement Procedure for Standard and Sample/Batch:
After completing the calibration procedure, the data color is ready for use. The measurement
procedure for standard sample-
Place the standard sample on the probe/port of the datacolor carefully
 Click the new std. button on the desktop. This clears the Name field, and places the
cursor in the field.

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 Enter a name for the sample.
Sample data can come from the instrument, the database or the keyboard. On the desktop
there are two buttons that identify the origin of the standard and batch measurements.
The measurement method is set independently for each sample type. In this example, both the
standard and the batch measurement come from the instrument (Inst). Place the standard at
the instrument port, and click the Std:Inst button to start the measurement.
The sample just measured becomes the current standard on the desktop. Data fields on the
desktop will be updated to display the data for the sample just measured.

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Evaluations:
Color Evaluations:
Once you have selected a standard or batch, there are numerous color evaluations you can
perform. Typically, the Datacolor TOOLS desktop includes several color evaluations
including color differences, pass/fail, color plots etc. The color evaluation displayed is always
based on the current standard and batch data on the desktop.
Pass Fail Evaluation:
Below is an example of a pass/fail evaluation:
 Color Difference (DL*, Da*, Db*, DC*, DH*, and DE*). These are the color
differences between the batch (E8) and standard (STD GREEN PL). This example
includes differences between the samples on each individual parameter (DL*, Da*,
Db*, etc.) as well as DE*, the composite color difference. See Applications
Technology, Interpreting Color Differences for a detailed discussion of color
difference output.
 Illuminant/Observer (Ill/Obs) Condition (D65/10 deg, A/10 Deg, and F2/10 Deg).
These are the Illuminant and Standard Observer selections being used for the
evaluation. The color differences between the standard and the batch are provided for
each Illuminant/Observer condition. The color differences between the samples do
not remain the same when the illuminant or observer is changed.
 Pass/Fail Determination. If the batch color difference is within the tolerances set for
the standard, the program will display PASS. If outside the tolerances, the batch

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FAILS. See Applications Technology Acceptability Tolerances for a detailed
discussion of pass/fail tolerances.
 Descriptors (Batch is lighter, more saturated, more yellow). Translates the numerical
color differences into a qualitative description of the color differences for the first
Illuminant/Observer condition.
Functions of Data Color:
Colorant sets:
A colorant set is a set of color information about the substrate and dyes the system uses to
produce match and correction recipes. It contains-
 Information about the overall colorant set (the substrate and process that will be used
with the dyes).
 Product information about each dye (strength, minimum and maximum concentrates).
 Color information about each dye.
Colorant set procedure:
 Open the “Colorant set list” window.
 On the “Colorant Set” or the context sensitive menu, select New Textile.
 Specify the name and the identification of the new colorant set.
 Click in the “Dye Process”, “Substrate Delivery” and “Operation” field opens the
corresponding selection box. Select input from on the context sensitive menu of the
selection box to specify a new object.
 Click Store.
Recipe Calculation:
 Open the “Recipe List” window.
 On the “Recipe” or the context-sensitive menu, select “Calculate” or press F5.
 Select the quality style and the combined process.
 If necessary, select the substrate delivery.
 Select the colorant ste(s).

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 Select the “Standard” to be matched.
 If we have to re-dye, select the dyed substrate or re-measure it.
 In the “Colorant Set” tab select the dyestuff to by used and select or specify a dyestuff
group.
 In the “Setting” tab, select the parameters for the matching process.
 Click Calculate to immediately start the recipe calculation. The recipe table appears.
 Select the recipes we want to dye.
 Click close or Save to save the recipe.
Recipe Correction:
Laboratory Correction recipe procedure:
 Select the recipe to be corrected in the “Recipe List” window.
 On the context-sensitive menu, select Pass Fail and Laboratory Correction, or Press
F6.
 Click Pass Fail and Correction.
 In the “Batch and Color Difference” field, measure or select the sample.
 If necessary, alter the data in the dyestuff table.
 Click Save to save a manual correction. The correction recipe is saved.
 Click Laboratories. The “Recipe Correction” table appears.
 In the “Recipe Correction” dialogue box, we can look at the result of the matching the
color differences between “Standard” and “Batch” are displayed.
 If finished close the recipe table.
 Click Yes.
 Select the recipe output(s) according our needs, and/or close the “Show Full Recipe”
dialog box.
Production Correction recipe procedure:
 Select the recipe to be corrected in the “Recipe List” window.
 On the context-sensitive menu, select Pass Fail and Laboratory Correction, or Press
F7.
 Click Productions.

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 We can optimize the result of the matching by adding dyestuff and concentrations and
by specifying tolerances.
 When finished, we can display and print the recipe.
 Click close to close the “Production Correction” dialog box.
Basic components of Datacolor:
All spectrometer instruments designed to measure the absorption of radiant Energy have the
basic components as follows:
 A stable source of radiant energy (Light).
 A wavelength selector to isolate a desired wavelength from the source (filter or
monochromic).
 Transparent container (curette) for the sample and the blank.
 A radiation detector (phototube) to convert the radiant energy received to a
measurable signal and a readout device that displays the signal from the detector.

Spectrophotometer wroking procedur

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