Predavanje"Gamut Volume as a Tool for the Evaluation of Image Permanence"

Pozvani ste na predavanje “Gamut Volume as a Tool for the Evaluation of Image Permanence“, koje će održati Izv. prof. Petr Dzik dr. sc. sa sveučilišta Brno University of Technology, Faculty of Chemistry, Czech Republic u okviru Erasmus Staff  Traininga.

Predavanje će se održati u četvrtak 17. studenoga 2011. godine u 12 sati u dvorani A na Sveučilištu u Zagrebu, Grafički fakultet (Getaldićeva 2).

Kratki sadržaj predavanja

Photography as a part of the cultural heritage is an ever-lasting subject of various stability experiments and analyses. This testing has become more important in recent years as new digital printing techniques have been penetrating the market and recieving acceptance from the graphic arts professionals. However, it seems the application of traditional fading test and standards developed for the silver-halide photography is not straightforward and brings many controversies. The shift from densitometric monitoring of print fading towards colorimetric one is obvious and generally accepted. On the other hand, methods for print life estimation from colorimetric data are still being debated.
The proposed paper deals with one of such methods. Gamut volume calculated as a convex hull of a set of points plotted in the L*a*b* color space seems to be a promising approach. The authors will report their recent advanced in this field. Unlike the previous work, this time a well defined set of mathematical transformations derived from the Q-hull algorithm (executed in a  proprietary software developed in Matlab) is used to calculate  the gamut volume.
Practical application of the method will be demonstrated on a set of samples produced by classic chromogenic and modern digital printing processes. Accelerated color fading was induced by exposure to high-intensity light. Measured spectral data were converted into L*a*b* coordinates and corresponding gamut volumes were calculated.  Relative gamut volume changes plotted as a function of exposure dose were then used to determine rate parameters, which can be used to compare the lightfasness of different media or predict their lifetime.