FRS 123 - Technology in Art and Cultural Heritage

Fall 2006

Assignment 3

Due Wednesday, Nov. 29

In this assignment you will use Photoshop or another image editing tool to produce an illustration starting from one or more images.

COMPLETE BOTH OF THE FOLLOWING PARTS:

1. Illustration starting with multiple images

One of the hallmarks of good medical and technical illustrations is that they clearly depict things that are not visible in a single photograph. Your assignment is to start with a collection of images of the same object under different lights, and produce an illustration that combines the best parts of the images (e.g., eliminates shadows, includes strategically-placed highlights, emphasizes contrast in different regions, etc.). The best way to do this is probably to load the images as separate layers, then use the eraser tool to erase parts you don't want, letting other layers show through. Also, feel free to experiment with contrast/brightness adjustment, edge detection, and other tools to produce a compelling illustration.

Here are a few suggested datasets you may start from (pick one):

There are other multi-image datasets available here: look for the links labeled with (PNG). (Warning: these contain 252 light positions, and are very large.)

For extra credit, try to take your own dataset of some object you think will be interesting. It is critical that the camera not move between shots, so a tripod and/or remote control for your camera are suggested.

2. Conveying brightness

In this part, you will start with an image of a scene of your choice (taken by you or downloaded from the Web), and produce two modified versions: one yielding a convincing impression of the scene in extremely bright light, and one yielding a convincing impression in dim light. In addition to changing the overall brightness and contrast, try including some of the effects we talked about in class (loss of color perception in dim scenes, glare and color bleaching in bright scenes), as well as some other "tricks of the trade" used in cinematography (such as a subtle blue shift to convey an impression of night-time).

Submitting your results

For part 1, send us your final illustration. For part 2, send in the original image, as well as the "bright" and "dark" versions. Include a description of the effects you were trying to achieve, as well as the specific techniques you used to achieve them. Send everything in an email to smr@cs.princeton.edu.

Photoshop / Gimp hints

Be sure to save your image in both the software's own format (PSD for Photoshop, XCF for Gimp), which saves all layers separately, and a format such as JPEG for your final result (which collapses everything into a single image).

Last update 29-Dec-2010 11:58:01

smr at princeton