This assignment has two parts, and is due at the beginning of class on Tuesday, February 13:
- 5a. Hatching Studies (50 points, 3 hours)
- 5b. Hatched Photograph (50 points, 3 hours)
Please read this prompt all the way to the end, before you start any drawing or coding. The purpose of this prompt is for you to develop foundational skills in controlling value and tone.
First, a warmup exercise: By hand, with a pen and paper, draw some hatching studies (i.e., ways of approximating gray tones using assemblies of lines, in order to fill areas of paper). Specifically: Generate 9 different hand-drawn hatching concepts or styles (say, in a 3×3 grid)—starting with the most obvious and simple hatching methods, and aiming for some more exotic hatching methods that you might not have any idea how to implement in code. For each hatching style/concept, draw a "value scale" in which you explore how that method achieves variations in density.
Now:
- Write code to implement four different methods of hatching. You're not required to implement any method that you sketched earlier, but you're welcome to do so.
- For each hatching method, create a value scale (gradient sequence) of five adjacent one-inch squares, with evenly-spaced gray values of 10%, 30%, 50%, 70%, 90%. Some inspirations can be seen below.
- Export a single SVG with all four hatching sequences, and plot this using a thin black pen on a sheet of heavy white paper. (Alternatively, you may use a white pen on black paper.) If you use 11x8.5" paper, you will have the option to use the (fast) HP7475a plotter (instructions here).
- Create a Discord post in the #5a-hatching-studies channel.
- (5 points) In your Discord post, embed a photo of your 3×3 grid of handmade sketches.
- (40 points, i.e. 10 points for each of the four methods) In your Discord post, embed a photograph of your plot with the four computer-generated value sequences.
- (5 points) In your Discord post, please write a sentence to describe each of your hatching methods, and what you learned making them. Did you have any surprises? Remember to give credit to any external code sources you may have used.
In your designs,
- Consider methods like: hatching, cross-hatching, scribbling, scumbling, stippling, fill patterns, or other creative methods of your own design. If you're feeling ambitious and self-directed, this is a perfect opportunity to explore how you can create hatching techiques using things like Perlin noise flow fields, physics simulations (e.g. particle systems, Lloyd's relaxation), typography (e.g. Hershey fonts), etc.
- Consider how you can productively control and contrast properties like: line direction, line density, line length, line curvature, line thickness, and line duty cycle (dashes) to produce different hatches with different characters. Consider how you can control the variation (e.g. randomness, or standard deviations) of these properties. Do any of your hatching methods have more than one expressive variable (apart from value/density)?
- "Easement" 1: For up to two of of your hatching methods, you are permitted to integrate “readymade” hatching code into your project (i.e., literally made by someone else — such as you might find in a high-level library like e.g. PEmbroider, Cartopy, PyGeode, or PySLM). You may use such a library for no more than two of your four different hatch methods. An example project using PEmbroider is given here. Note that using an external library will not necessarily save you any time (why?).
- Easement 2: For one of your hatching methods, feel free to implement the following extremely simple method shown immediately below, using parallel lines. I have posted the code for this method here in case you'd like to peek at an example solution.
AxiDraw hatching by Lars Wander.
(50 points). In this exercise, you will devise a method to render a continuous-tone photograph using the plotter. The objectives of this project are:
- To learn how to convert or transduce raster images into vector representations, and/or
- To learn how to represent gradations of continuous tone through hatching, dithering, halftones, or related techniques.
Now:
- Write code to implement a hatching method capable of transducing a continuous-tone photograph into a vector file for plotting.
- SAMPLE CODE. Here is some sample code to get you started:
- weighted rejection sampling of an image in p5.js
- line hatching in grid-based image subdivision in p5.js
- line hatching in grid-based image subdivision in Processing (Java)
- line hatching in grid-based image subdivision in Processing (Python)
- Choose a photograph to transduce with the plotter. Your photograph should depict a subject for which you have some meaningful personal investment, such as a portrait of someone you know personally (friend, family, self).
- Give consideration to the relationship between your subject (who/what) and your hatching method (how). Ideally, these will be tightly coupled: you will choose a photo for a specific rendering treatment, and/or develop a rendering treatment for a specific photo.
- Apply your hatching technique to the photograph, and plot the result. You may plot using any colors of pen and paper you like, but it is recommended (for purely practical reasons) that you limit yourself to one color of pen.
- Create a Discord post in the #5b-hatched-photo channel.
- (35 points) In your Discord post, embed a photograph of your plotter drawing.
- (5 points) In your Discord post, embed a copy of your original source photograph.
- (10 points) In your Discord post, please write a couple sentences about your process. Evaluate your work.
Additional remarks:
- The purpose of my asking you to make a portrait of (e.g.) a friend or loved one is to ensure that you have some sort of meaningful investment in the subject of your image. If there is a different subject that you would prefer to use (such as your cat, etc.), that's fine.
- You may not create a portrait of a celebrity, nor of the professor.
By Algorigraph.
By Golan Levin, 1999.