Shading with Painterly Filtered Layers: A Process to Obtain Painterly Portraits
Abstract
In this thesis, I study how color data from different styles of paintings can be extracted
from photography with the end result maintaining the artistic integrity of the art style and having the look and feel of skin. My inspiration for this work came from the impasto style portraitures of painters such as Rembrandt and Greg Cartmell. I analyzed and studied the important visual characteristics of both Rembrandt’s and Cartmell’s styles of painting.These include how the artist develops shadow and shading, creates the illusion of subsurface
scattering, and applies color to the canvas, which will be used as references to help
develop the final renders in computer graphics. I also examined how color information
can be extracted from portrait photography in order to gather accurate dark, medium, and light skin shades.
Based on this analysis, I have developed a process for creating portrait paintings from
3D facial models. My process consists of four stages: (1) Modeling a 3D portrait of the
subject, (2) data collection by photographing the subjects, (3) Barycentric shader development using photographs, and (4) Compositing with filtered layers. My contributions has been in stages (3) and (4) as follows: Development of an impasto-style Barycentric shader by extracting color information from gathered photographic images. This shader can result in realistic looking skin rendering. Development of a compositing technique that involves filtering layers of images that correspond to different effects such as diffuse, specular and ambient.
To demonstrate proof-of-concept, I have created a few animations of the impasto style
portrait painting for a single subject. For these animations, I have also sculpted high
polygon count 3D model of the torso and head of my subject. Using my shading and compositing techniques, I have created rigid body animations that demonstrate the power of my techniques to obtain impasto style portraiture during animation under different lighting conditions.
Citation
Castaneda, Saif Aymen (2017). Shading with Painterly Filtered Layers: A Process to Obtain Painterly Portraits. Master's thesis, Texas A & M University. Available electronically from https : / /hdl .handle .net /1969 .1 /165954.