FLUORESCENCE and PHOSPHORESCENCEQuality Control in the printing industry

Dipl.Ing. Lukas Pescoller

FAG Graphic Systems SA

www.fag.ch

Luminescence Terminology

In Fluorescence a substance‘s glow is triggered by (UV) light. The substance absorbs light and emits light of a longer wavelength while the light source is on.

In Phosphorescence a substance‘s glow is triggered by (UV) light. The substance absorbs light and emits light of a longer wavelength and continues after the light source has been switched off.

Other Luminescence types are triggered by a chemical reaction, electricity, X-rays, sound, temperature, mechanical impact.

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Luminescence

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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1. Excitation

energy from

photon of a

short wavelength

2. Electron is raised to a

higher energy level

3. Electron spontaneously

falls to lower energy,

emitting photons of

longer wavelength

Fluorescence and Phosphorescence

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Fluorescence light emission

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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UV Light onE

mitte

d lig

ht in

vis

ual ra

nge

glowingNot

glowing

UV Light off

Phosphorescence light emission

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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UV Light onE

mitte

d lig

ht in

vis

ual ra

nge

glowing

still

glowing

UV Light off

Design a fluorescence sighting feature

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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FAG FLUODX Fluorescence and Phosphorescence Colorimeter

Fluorescent intensity production quality control

Phosphorescent production quality control

Fluorescent color Analysis (XYZ, xy, Lab, LCh, BiFL, Delta E)

Phosphorescence Analysis

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Fluorescence and Phosphorescence Quality Control in the press room

Add invisible ink patches to the color bar

Invisible inks are invisible if not exposed to UV light

Add a black frame to invisible ink patches in the color bar

Add a description to the invisible ink patches in the color bar

Measure the invisible ink patches using the FLUO DX colorimeter

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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FRG

FB

FR

B

FB

G

RFR

B dE

FG CMYK

Fluorescent Ink Quality Control in the Press RoomSetup a reference

Select the FilterRGB K=R+G+BA = auto detection

Measure ReferenceMeasure several times to obtain a solid average reference intensity

Save ReferenceSave the reference

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Fluorescent Ink Quality Control in the Press RoomMeasure a production sheet against a reference

Measure a production sheetUp to 20 MeasurementsMost recent reading can be deleted

Save using a MarkAll measurements are savedTake a note of the Mark on the sheetSheet overview as bar diagram

Display statisticsSave the reference

Measure next sheet

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Upload Data to the PC

Measurement data can be uploaded via IRDA using the FLUO IRDA Interface box or via USB cable connecting the FLUO DX to the USB Port.

Data can be exported to a tab-delimited text file for further analysis

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Phosphorescent Ink Quality Control in ProductionDetermine measurement parameters using FLUODXConnect Software

Select the filter according to phosphorescence color

Set the timing parameters

Test the Exposure Energy required to cover the tolerance range

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Setting for typical sample

Wait O

FF

Tim

e

Exposure Time

PhosphorescenceFluorescence

E=18%

E=15%

E=10%

Phosphorescent Ink Quality Control in the Press RoomConfigure measurement parameters using FLUODXConnect Software

Two Phosphorescent Ink parameter sets can be configured; PH365A and PH365B

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Phosphorescent Ink Quality Control in the Press RoomSetup a Reference

Select the FilterRGB

Measure ReferenceMeasure several times to obtain a solid average reference intensity

Make sure to wait between two readings to fully discharge the phosphorescent sample

Save ReferenceSave the reference

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Phosphorescent Ink Quality Control in the Press RoomMeasure a production sheet against a reference

Measure production sheetUp to 20 MeasurementsMost recent reading can be deletedPh365 = Signal after Cool Down TimePh365Ind = Phosphorescence / Fluorescence ratio

Save using a MarkAll measurements are savedTake a note of the Mark on the sheetSheet overview as bar diagram

Display statisticsPhosphorescence Statistics

Measure next sheet

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Upload Data to the PC

Measurement data can be uploaded via IRDA using the FLUO IRDA Interface box or via USB cable connecting the FLUO DX to the USB Port.

Data can be exported to a tab-delimited text file for further analysis

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Color Analysis

Measure the Sample several times. The average of the measurements will be calculated and displayed.

Select the Color Information you need

Save the measurement. Averaging will restart with subsequent measurement

Saved measurements can be uploadedto the PC

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Check the BiFluorescence of a sample

When measuring with F256, the BiFL Information isdisplayed in addition to other color information

Ratio

The sample glows 34% as strongly when excited with 256nm as it glows when excited with 365nm

Hue

The sample glows in cyan color when excited with 256nm but it glows in blue color when excited with 365nm

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Analyze PhosphorescenceConfigure the measurement parameters using the FLUODXconnect Software

Set Timing for Wait OFF, Exposure, Cool Down

AK1/2: Decay time after switching light source off until the specified % of the signal strength is reached

Tau Interval: calculate the Tau of the decay curve f(t) based on the specified interval

Select Filter

Select the Light intensity

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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𝑓 𝑡 = 𝑒−𝑡

𝑇𝑎𝑢

Measure Phosphorescence

IntPH: after DT(10.0ms) the decay signal has reached 22% of the Fluorescence Signal

Chg/dchg: The sample charging time until saturation is estimated to be at least 61ms. The discharging time is estimated to be 19.3ms

Phl 50/20: 0.4ms after the illumination has been switched off the signal glows still 50%.

Phl 50/20: 6.7 ms after the illumination has been switched off the signal glows still 20%.

Save the measurement and upload it later on to your PC

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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Measure Delta E with 256nm or 365nm illumination

Measure the Target several times. The average of the measurements is calculated and displayed

Measure the sample several times. The average of the measurements is calculated and displayed

Save the measurement and upload it to the PC later

6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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6/17/2020 Dipl.Ing. Lukas Pescoller, FAG Graphic Systems SA www.fag.ch

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See what happens

Understand why it happens

Take corrective actions