OBJECTIVE To test the null hypothesis that there is no color change when enamel porcelain thickness is changed and to evaluate the ability of a shade guide to prescribe chroma. METHODS Three shades (3M1, 3M2 and 3M3) were selected from a Vitapan 3D master shade guide. Five disk specimens were prepared for each shade, consisting of three layers (opacious dentin, dentin and enamel) at thickness...

Perception of peripherally viewed shapes is impaired when surrounded by similar shapes. This phenomenon is commonly referred to as "crowding". Although studied extensively for perception of characters (mainly letters) and, to a lesser extent, for orientation, little is known about whether and how crowding affects perception of other features. Nevertheless, current crowding models suggest that t...

UNLABELLED PREMISE OF THE STUDY Differences in color form a major component of biological variation, and quantifying these differences is the first step to understanding their evolutionary and ecological importance. One common method for measuring color variation is segment classification, which uses three variables (chroma, hue, and brightness) to describe the height and shape of reflectanc...

background: natural antioxidants with plant origin are incorporated to foods in the forms of essential oils or extracts. they can retard lipid oxidation and control spoilage bacteria in foodstuffs (e.g. meat products). objective: this work was aimed to evaluate the effect of nitrite partial replacement with mentha piperita essential oil (mpeo) on oxidative, microbial and sensory properties of c...

Colour development in fruit of Actinidia chinensis var. chinensis ‘Hort16A’, the new yellowfleshed cultivar produced commercially in New Zealand, was monitored during three seasons in four 42 New Zealand Journal of Crop and Horticultural Science, 2003, Vol. 31 The pericarp of ‘Hort16A’ fruit changes from a light green colour to a light yellow colour as fruit develop on the vine. Virtually no co...

The precision of human colour discrimination depends on the region of colour space in which measurements are made and on the direction in which the compared colours-the discriminanda-differ. Working in a MacLeod-Boynton chromaticity diagram scaled so that thresholds at the white point were equal for the two axes, we made measurements at reference points lying on lines that passed at 45° or -45°...