*************README file for*********************************** GRAFI-r: Gravure printing finger instability dataset (raw data) *************************************************************** Last modified: 2024-01-10 (yyyy-mm-dd) This dataset was generated by Pauline Rothmann-Brumm (2023) as part of her dissertation at the Technical University of Darmstadt, Germany. Title of the dissertation: Visualisierung, Analyse und Modellierung von fluiddynamischen Musterbildungsphänomenen im Zylinderspalt unter Anwendung von Maschinellem Lernen (German) / Visualization, analysis and modeling of fluid dynamic pattern formation phenomena in the cylinder gap using machine learning (English translation) --------------------- DATASET DESCRIPTION URL: https://tudatalib.ulb.tu-darmstadt.de/handle/tudatalib/3842 The GRAFI-r dataset contains high speed videos of finger instabilities during fluid splitting in gravure printing. The high speed videos were recorded on a custom-built gravure printing research platform, which enables optical access to the printing nip. The printing nip is the line of contact between the engraved printing cylinder and the impression roller. The aim of the dataset is the in-situ visualization and temporal analysis of hydrodynamic pattern formation phenomena during fluid transfer. The influence of the engraving raster on the finger instability can be investigated. The GRAFI-r dataset comprises raw video data whereas processed video data can be found in the related GRAFI-p dataset (see https://tudatalib.ulb.tu-darmstadt.de/handle/tudatalib/3848). GRAFI-r dataset stands for gravure printing finger instability dataset. The suffix -r stands for raw data. --------------------- METADATA Here, only a selection of the metadata is given, the full metadata of the GRAFI-r dataset can be found in the dissertation of Pauline Rothmann-Brumm. The dataset consists of 137 high speed videos, which were recorded with a Photron Fastcam Nova S12 high speed camera. Each video is available as high-quality TIFF-images (see .ZIP-folders) as well as compressed MP4-video-files for quick and easy viewing. The MP4-video-files can be viewed with any standard video player e.g. VLC media player. The TIFF-image sequences can be viewed with e.g. Fiji ImageJ (using File --> Import --> Image Sequence) or the Photron Fastcam Viewer 4 software (download here: https://photron.com/de/photron-support/) by opening the provided CIHX-file for each video in the ZIP-folder. Resolution of the videos is 34 micrometer/pixel at a total size of 640 pixel x 480 pixel per frame. The frame rate of the video recordings is 30,000 fps (frames per second). Scale bar and time stamps are added to the MP4-video-files. The videos are named according to their printing parameters. Example: R060_V0250_GRA_01 R060 --> Raster frequency of the engraved printing form of 60 lines/cm. Other used raster frequencies: 80 lines/cm and 100 lines/cm. V0250 --> Printing velocity of 250 mm/s. Other used printing velocities: 500 mm/s, 1000 mm/s and 2000 mm/s. GRA --> Abbreviation for the used printing fluid. GRA: Red, water-based gravure printing ink (R0001235761 red-bluish from Sun Chemical, Niedernhausen, Germany - alternative product name: RW2700) diluted with water to a viscosity of 14 sec in a 4 mm DIN flow cup (DIN 53211) or equivalently 24 sec in a 4 mm ISO flow cup (DIN EN ISO 2431). AIR: Videos without printing fluid. 01 --> Number of video. The used electromechanically-engraved printing form has a tonal value of 100 % and a raster angle of 59.35°, which corresponds to HELL raster angle #2 (HELL Gravure Systems GmbH & Co. KG, Kiel, Germany). The stylus angle for engraving is 120°. The gravure printing research platform uses a Gorilla glass substrate, which was directly printed onto. --------------------- CONTACT Pauline Rothmann-Brumm Technical University of Darmstadt, Department of Mechanical Engineering, Institute of Printing Science and Technology (IDD), Magdalenenstr. 2, 64289 Darmstadt, Germany rothmann-brumm@idd.tu-darmstadt.de