Branka Lozo

Colorimetric properties and stability of 3D prints

Purpose – The purpose of this paper is to evaluate and discuss colour properties, stability and lightfastness after accelerated exposure in xenon‐arc light apparatus, of 3D ink jet prints produced by using 3D colour printing process.Design/methodology/approach – 3D colour prints were produced using ZCorporation 3D printing method. The samples were divided into groups according to the finishing process applied (untreated, finished with different infiltrants). Colorimetric properties were measured using spectrophotometer. Samples were placed into xenon‐arc based weathering apparatus (Xenotest), using the preset glass filtered sunlight, standard indoor conditions. Colour stability was evaluated as change in colour after repeating the spectrophotometer measurements and comparing spectral and specific colorimetric values of initial and exposed samples.Findings – Based on methodology used, the analysis has shown the changes in colour appearance of differently finished 3D prints, which were mostly attributed to ...

Multi-color 2D Datamatrix codes with poorly readable colors

Datamatrix code is a type of 2D codes that can encode much more data on the same or smaller area than the linear barcodes. This makes 2D codes usable for marking even very small items. 2D codes can be decoded by the readers in retails but also with the mobile phones equipped with camera and appropriate software. 2D codes can be depicted in different materials or printed on different printing substrates. The application of the codes is broad, from magazines and newspapers to posters and packaging. Successful reading of 2D codes is possible if the code is printed in appropriate contrast between the printing ink and substrate, like black ink printed on white matt paper. Problems can occur if the code is printed in colors. The readability of 2D Datamatrix codes printed in cyan, magenta, yellow and black was studied. Yellow is proved to be poorly readable. In addition, the bi-colored and multi-colored 2D Datamatrix codes were studied. When four colors are used in creation of the 2D Datamatrix code, poorly readable elements, yellow codewords, may cause the reading failure. 2D Datamatix codes are capable to ensure good readability even if they contain a defined number of poorly readable codewords due to the Reed – Solomon error-correction system. The aim of the study was to determine the position of yellow printed, poorly readable, codewords in multi-colored 2D Datamatrix code, where the code still remains readable.