I tried to create painterly expression, especially oil painting, for my second midterm project of Pixel by Pixel class.
There are various painting styles. Then, what makes the difference between oil painting and other paintings or drawings?
First, I think, the materials of oil paints and oil painting brush make very unique features of oil painting. The thick oil paints produce even 3D effect on canvas and the brush creates brush texture due to its stiff hair. To get closer to the features, I took several pictures of real oil painting brushes and changed their colors to gray tone which would be able to accept the colors of source image.
Second, in the process of real painting, painter uses different size of brushes, usually painting broad area first with big size of brush and then getting into details with smaller one even though it is different depending on painters’ style. Therefore I made three layers of three brush sizes, big, middle and small. After applying first big brush, I compared the brightness of the screen image to the one of source image. If the difference of the brightness is big, I think, that means ‘details’ which need more painting with smaller brush. After applying second middle brush, I did the same way before third small brush.
<Image painted by first big brush>
The third thing what I did was about ‘color’. I think painter can’t replicate the color of reality on canvas because he/she has many limitation to do that; the limitation of perception, materials he/she uses and his/her hand skill. Instead those limitations make painter’s own style. Thus the colors we can see on paintings are very limited and I tried reducing the numbers of colors for brush strokes. By the way, reducing colors without considering and doing research on colors of real painting resulted disappointing images. I thought manipulating color had lots of possibility of expressing more stylish painting so I decided not to use this idea for this time and put aside for further work.
The last one is about ‘outline’. Outline may not be necessary in some paintings but some may need it. To draw an outline, I used edge detection and tried to draw different brush with other brushes on that edge. However, I continuously got an error. I think I can use edge detection both to draw outline with darker color than neighbor colors and to make the direction of strokes follow the edge’s(now the direction of stroke is random). That will be also the next step of my challenge in painterly expression project.
Here is the code.
http://itp.nyu.edu/~sjh376/testApp.cpp
The analytic approach of this project is based on the research experience on NPR(Non-Photorealistic Rendering) technique, when I was a graduate student of ChungAng Unuversity in Korea. The research was a joint project between the lab which I was belonged to and was mainly consisted of artists and designers and the lab consisted of engineers. I took the responsibility of analyzing art, especially oil painting in technique and Impressionism in genre, and converting the facts from the analysis to the guidelines and materials which were applicable to the process of developing algorithm. The research resulted ‘Painterly Rendering with Designed Imperfection’, the installation artwork exhibited in Guerilla Studio, SIGGRAPH 2006. Also my master’s thesis is ‘Study for Non Photorealistic Rendering based on Aesthetic Analysis’.
The motive which had made me get interested in NPR technique was the idea of painterly abstract animation. I’ve wanted to apply NPR to my animation. Therefore, doing midterm assignment, I was excited to realizing some parts of my analysis with openframeworks by myself. Applying current code to moving image is another matter because oil painting and the animation using oil paints have different process of making and thus give us different feeling. That’ll be also my next challenge until I can realize what I imagine.
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