Use of Multispectral Microscopy in the Prediction of Coated Halftone Reflectance
When a print is coated with a transparent layer, such as a lamination film or a varnish layer, its color can be modified compared to the uncoated version due to multiple reflections between the layer-air interface and the inked substrate. These interreflections involve a multiple-convolution process...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-09-01
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| Series: | Journal of Imaging |
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| Online Access: | https://www.mdpi.com/2313-433X/8/9/243 |
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| author | Fanny Dailliez Mathieu Hébert Lionel Chagas Thierry Fournel Anne Blayo |
| author_facet | Fanny Dailliez Mathieu Hébert Lionel Chagas Thierry Fournel Anne Blayo |
| author_sort | Fanny Dailliez |
| collection | DOAJ |
| description | When a print is coated with a transparent layer, such as a lamination film or a varnish layer, its color can be modified compared to the uncoated version due to multiple reflections between the layer-air interface and the inked substrate. These interreflections involve a multiple-convolution process between the halftone pattern and a ring-shaped luminous halo. They are described by an optical model which we have developed. The challenge at stake is to observe the impact of the coated layer on the print spectral reflectances and see if it can be predicted. The approach is based on pictures of the print captured with a multispectral microscope that are processed through the optical model to predict the spectral pictures of the coated print. The pictures averaged on the spatial dimension led to spectral reflectances which can be compared with macroscale measurements performed with a spectrophotometer. Comparison between macroscale measurements and microscale measurements with a multispectral microscope being delicate, specific care has been taken to calibrate the instruments. This method resulted in fairly conclusive predictions, both at the macroscale with the spectral reflectances, and at the microscale with an accurate prediction of the blurring effect induced by the multi-convolutive optical process. The tests carried out showed that the optical and visual effect of a coating layer on single-ink or multi-ink halftones with various patterns can be predicted with a satisfactory accuracy. Hence, by measuring the spatio-spectral reflectance of the uncoated print and predicting the spatio-spectral reflectance of the coating print, we can predict the color changes due to the coating itself. The model could be included in color management workflows for printing applications including a finishing coating. |
| first_indexed | 2024-03-09T23:33:48Z |
| format | Article |
| id | doaj.art-1a3e6710804144f1ad53bb2f4f41beaa |
| institution | Directory Open Access Journal |
| issn | 2313-433X |
| language | English |
| last_indexed | 2024-03-09T23:33:48Z |
| publishDate | 2022-09-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Journal of Imaging |
| spelling | doaj.art-1a3e6710804144f1ad53bb2f4f41beaa2023-11-23T17:04:40ZengMDPI AGJournal of Imaging2313-433X2022-09-018924310.3390/jimaging8090243Use of Multispectral Microscopy in the Prediction of Coated Halftone ReflectanceFanny Dailliez0Mathieu Hébert1Lionel Chagas2Thierry Fournel3Anne Blayo4Univ Grenoble Alpes, CNRS, Grenoble INP (Institute of Engineering Université Grenoble Alpes), LGP2, F-38000 Grenoble, FranceUniv Lyon, UJM-Saint-Etienne, CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, F-42023 Saint-Etienne, FranceUniv Grenoble Alpes, CNRS, Grenoble INP (Institute of Engineering Université Grenoble Alpes), LGP2, F-38000 Grenoble, FranceUniv Lyon, UJM-Saint-Etienne, CNRS, Institut d’Optique Graduate School, Laboratoire Hubert Curien UMR 5516, F-42023 Saint-Etienne, FranceUniv Grenoble Alpes, CNRS, Grenoble INP (Institute of Engineering Université Grenoble Alpes), LGP2, F-38000 Grenoble, FranceWhen a print is coated with a transparent layer, such as a lamination film or a varnish layer, its color can be modified compared to the uncoated version due to multiple reflections between the layer-air interface and the inked substrate. These interreflections involve a multiple-convolution process between the halftone pattern and a ring-shaped luminous halo. They are described by an optical model which we have developed. The challenge at stake is to observe the impact of the coated layer on the print spectral reflectances and see if it can be predicted. The approach is based on pictures of the print captured with a multispectral microscope that are processed through the optical model to predict the spectral pictures of the coated print. The pictures averaged on the spatial dimension led to spectral reflectances which can be compared with macroscale measurements performed with a spectrophotometer. Comparison between macroscale measurements and microscale measurements with a multispectral microscope being delicate, specific care has been taken to calibrate the instruments. This method resulted in fairly conclusive predictions, both at the macroscale with the spectral reflectances, and at the microscale with an accurate prediction of the blurring effect induced by the multi-convolutive optical process. The tests carried out showed that the optical and visual effect of a coating layer on single-ink or multi-ink halftones with various patterns can be predicted with a satisfactory accuracy. Hence, by measuring the spatio-spectral reflectance of the uncoated print and predicting the spatio-spectral reflectance of the coating print, we can predict the color changes due to the coating itself. The model could be included in color management workflows for printing applications including a finishing coating.https://www.mdpi.com/2313-433X/8/9/243halftone colorsoptical modelscolor imagehyperspectral imagingspectral reflectancecoating |
| spellingShingle | Fanny Dailliez Mathieu Hébert Lionel Chagas Thierry Fournel Anne Blayo Use of Multispectral Microscopy in the Prediction of Coated Halftone Reflectance Journal of Imaging halftone colors optical models color image hyperspectral imaging spectral reflectance coating |
| title | Use of Multispectral Microscopy in the Prediction of Coated Halftone Reflectance |
| title_full | Use of Multispectral Microscopy in the Prediction of Coated Halftone Reflectance |
| title_fullStr | Use of Multispectral Microscopy in the Prediction of Coated Halftone Reflectance |
| title_full_unstemmed | Use of Multispectral Microscopy in the Prediction of Coated Halftone Reflectance |
| title_short | Use of Multispectral Microscopy in the Prediction of Coated Halftone Reflectance |
| title_sort | use of multispectral microscopy in the prediction of coated halftone reflectance |
| topic | halftone colors optical models color image hyperspectral imaging spectral reflectance coating |
| url | https://www.mdpi.com/2313-433X/8/9/243 |
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