The Digital Eclipse DXM 1200 ACT-1 software has a time-lapse feature that allows the user to capture sequential images of dynamic events that occur under the microscope. The Timer settings panel is utilized to configure variables included in time-lapse experiments, and to start and stop recording of image sequences.

Access the Timer settings panel by clicking on the appropriate tab in the settings panel tab header. This panel is utilized to turn the time-lapse feature on and off through the Enable Timer checkbox located in the upper left of the panel window. 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 pixel size and file format type. File specifications are entered using the Save settings panel, and should be set prior to configuration of the time-lapse settings panel.

The time interval between sequential image captures is entered into the Interval Time text box, either by typing in the time in hours, minutes, and seconds, or by using the up- and down-arrow buttons located to the right of the text box. A minimum of 5 seconds must be entered as a time interval before the software will enable the time-lapse feature. Next, specify the total number of images to be captured in the Total Shots text box, which also has a set of arrow buttons that can be clicked to increment the number by a single digit up or down. Once these variables have been set in the panel, the software automatically calculates the total time for the experiment and displays this value in the Total Time window. Also calculated is the total file size assuming that the images are collected and stored as Windows bitmap image files. This value is presented in the Total File Size (Bitmap) window regardless of the actual file type used for image capture. Note that images in time-lapse experiments can be recorded as either *JPG (fine, normal, and basic), *.BMP, or *.TIF images.

After the experimental variables have been entered into the Timer settings panel and the Enable Timer function is activated, the Expose button evolves into a Start button that features a clock icon to indicate utilization of time-lapse cinemicrography features (Figure 2). Clicking on the Start button will allow commencement of time-lapse capture. The Enable Timer checkbox controls whether the Expose (Figure 2(a)) or Start (Figure 2(b)) button is displayed. When the checkbox contains a check mark, the time-lapse feature is turned on and the Start button is displayed. After the check mark is removed, the feature is deactivated and the Start button reverts back into the Expose button.

To initiate a time-lapse experiment, first configure the Timer settings panel and the file format, name, and folder where collected images will be stored. Next, click on the Start button to start capturing images by time-lapse cinemicrography. During image capture, the ACT-1 In Time Lapse Operation dialog box (Figure 3) appears with a blue indicator bar showing the relative progress of the experiment. The dialog box displays the selected time interval and the total number of images to be collected. Time remaining in the experiment and the number of images already captured are also indicated in the dialog box. In order to prematurely end the sequence capture, click on the Stop button located in the lower right-hand corner of the dialog box.

Images captured by the ACT-1 software time-lapse feature are automatically saved, regardless of the setting of the auto saving function in the Photo settings panel. The images are saved in the folder (directory) and under the filenames specified in the Save settings panel, in the file format selected in the Photo panel. Filenames have several other unique features that distinguish them from ordinary images stored by the ACT-1 software. A date stamp that includes the year, month, day, hour, minute, and second is automatically added at the end of the filename specified in the Save settings panel. This feature can not be disabled. In addition, an exclamation point (!) is inserted between the original filename and the date stamp, to allow the user to readily identify, from the filename, images captured by time-lapse cinemicrography. Note also that the auto printing function (a feature available in the Option settings panel) is disabled during use of the time-lapse sequential image capture routine.

An example of the time-lapse feature in the ACT-1 control software is presented in Figure 4 with a slowly recrystallizing sample of DDT (pesticide). The DDT crystals are first sandwiched between a microscope coverslip and slide, 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 DXM 1200 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 spherulite 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 DXM 1200 ACT-1 software should prove useful to many investigators concerned with recording slowly changing specimens in the microscope.