The DN100 camera control unit is equipped with a time-lapse cinemicrography feature that enables the user to capture sequential images of dynamic events that occur under the microscope. The REC submenu (Figure 1) is utilized to configure variables necessary for time-lapse experiments, and to start/stop recording of image sequences.

Access the REC submenu by right-clicking on the main display window and left-clicking the REC tab in the tab header of the submenus. This panel is utilized to turn the time-lapse feature on and off using the CARD button or the FTP button. In order to conduct time-lapse experiments, time intervals and the total number of digital images to be recorded must be pre-set before beginning the sequence acquisition. In addition, the user should also specify the storage location for digital time-lapse sequences, as well as the file name variables and the image size and file format type. File specifications are entered using the File Setting panel of the Setup Menu, and should be set prior to configuration of the REC submenu.

The time interval between sequential image captures is selected using the timer button by right- or left-clicking on the virtual button to choose the desired interval. The minimum time interval is 10 seconds, and the maximum interval is 6 hours. Next, specify the total number of images to be captured using the c:#### (Shots Count) button by right- or left-clicking the button to select the desired number of shots. Once these variables have been set, clicking the CARD or FTP button will initiate the time-lapse experiment. Note that images in time-lapse experiments can be recorded as either *.JPG (fine, normal, basic, and draft), or *.BMP images.

After the experimental variables have been entered into the REC submenu and the CARD or FTP button is activated, the Interval button automatically changes into a red Stop:INT button. Pressing this button will halt the time-lapse experiment. The Shots Count button will also turn red when the time-lapse sequence begins, and the button will begin to count down the number of shots remaining in the time-lapse sequence. Images captured by the DN100's time-lapse feature are saved in the folder (directory) and under the filenames specified in the File Setting panel, in the file format and size selected.

An example of the DN100's time-lapse feature is presented in Figure 3 with a slowly recrystallizing sample of aspirin. The aspirin crystals are first sandwiched between a microscope coverslip and slide, and then heated until melted on a hot plate. The coverslip is pressed firmly down to spread the molten chemical, and placed on a microscope stage to slowly cool. Images were captured with a Nikon Eclipse E600 polarizing microscope equipped with a DN100 camera system. The photomicrograph in Figure 4(a) was taken about 10 minutes after recrystallization had initiated. Over the next two hours, digital images were recorded at 30-second intervals. Figure 4(b) shows the crystalline growth pattern after 40 minutes, and Figure 4(c) depicts the same viewfield after 1.5 hours. After total recrystallization, the digital image in Figure 4(d) was captured to show the entire viewfield with an array of crystallites.

Time-lapse cinemicrography is an important tool for studying a variety of dynamic events using optical microscopy. Examples are crystal formation in biological, chemical, and geological systems, cellular movement and growth in tissue culture, intracellular processes observed with high-resolution fluorescence techniques, liquid crystalline phase transitions, and structural analysis of new materials in metallography. The sequential capture mode available with the DN100 camera control unit should prove useful to many investigators concerned with recording slowly changing specimens in the microscope.