9-21 September 2002
Throughout this semester, you are going to be observing embryos in development and documenting their appearance photographically. This week, you are going to learn to use two photomicroscopes, a digital camera, and you'll also be introduced to some simple image processing.
Everything needs to be done by Saturday, 21 September; note that this does overlap with the beginning of Lab 3. This lab is worth 20 points.
In this lab and all subsequent labs, you are going to be trying to produce esthetically magnificent works of scientific art. I'll be putting the best of your work on display in a gallery on the pharyngula web site, and particularly splendid images will be put on the main page.
I'll be demonstrating how to use this compound scope. This is a good tool for viewing relatively large specimens: whole embryos, whole adults, and any thick specimens which will not transmit light well. This is a relatively easy instrument to use, and most of the hard work will be in getting the lighting just right.
I will show you how to use the basic features of this microscope, which has options for brightfield, darkfield, phase contrast, differential interference contrast, and epifluorescence microscopy. Don't expect to master it in this one lesson! We'll try to set up the basics of good optics for you, but learning everything about it will be a gradual process over the course of the entire semester.
The Leica is the instrument to use for thin and transparent specimens, and for sectioned material.
IMPORTANT: this is an expensive tool; it costs as much as a mid-sized car, and some of the objectives alone are worth almost $1000 each. Please, always err on the side of caution, and I will always be happy to come work with you on it if you have any questions or problems at all.
Both the Wild and Leica scopes have camera tubes that allow you to attach a standard camera. We'll be using a Nikon Coolpix digital camera today, and in future labs I'll show you how to use a video camera. The Nikon takes 1600x1200 pixel still color images big, colorful pictures of whatever you're looking at on the scope and stores them on a compact flash memory card in the body of the computer. The memory card can hold over 50 pictures, and once you've shot what you need, you remove the compact flash card from the camera, plug it into the camera, and all of the data will be rapidly transferred to the Power Macintosh G4.
It costs nothing to take these pictures, and nothing to process them. So take lots of pictures. It is painless to push that shutter button and snap a shot whenever you want. Try different light intensities, different microscope settings, whatever. Pretend you are Austin Powers and go wild.
There is a separate handout to explain the basics of using the camera and transferring images.
There is also a separate handout for the image processing tool you'll be using, Adobe Photoshop. In many ways, Photoshop is serious overkill for the kinds of things you'll be doing, but it's also nice to have the power if you want to try something new. There are a few simple things that you will need to do routinely:
Each group will produce a web page that contains at least two photomicrographs from each student: one photo taken with the Wild, and another with the Leica. Each image should have a caption that explains what the subject is, what instrument was used to take it and what mode of microscopy was used, and an explanation of any unusual processing that was done. Grading will be on the basis of:
Imaging competence: Is the subject in focus? Is it framed properly, and are you taking advantage of the full dynamic range of the medium?
Layout competence: Does it have a scale bar? Do you explain what I'm looking at in your caption? Can you make a valid scientific point with this figure?
Esthetics: Is it beautiful? (Everything in biology is beautiful, so this shouldn't be too hard. I've seen photomicrographs of parasites in pig shit that were stunning works of art.)
Next lab: You'll be using your skills with the microscopes and computers to assemble a portfolio of images of chick embryos, from prepared slides.