Gatan DigitalMicrograph saves images, diffraction patterns and spectra as .dm3 or, in newer
versions, .dm4 (which also allows files over 4 GB). Both are tag files: the data sit next to a
tree of tags with the calibration, the microscope and camera settings and the display state.
This page reads that tree and writes the data as TIFF, PNG or CSV.
How to convert DM3 or DM4 to TIFF
- Upload the
.dm3or.dm4files, or a.zipof a folder of them. - Choose the picture format, the scale bar corner and colour, and the contrast (automatic, full range, or logarithmic for diffraction patterns).
- Download the TIFF for measuring in ImageJ or Fiji and the picture for slides and papers.
What is converted
- Images and stacks in every number type DigitalMicrograph uses: 8 to 64-bit integers, 32 and 64-bit float, complex images (also the packed format of FFTs, shown as log magnitude) and RGB. 8 and 16-bit data stay as recorded in the TIFF, other types become 32-bit float.
- Calibration. The pixel size and unit of each axis go into the TIFF, so ImageJ measures in nm or 1/nm. Images whose x and y pixel sizes differ keep both.
- Spectra. EELS, EDS and cathodoluminescence spectra become CSV files whose energy or wavelength column uses the origin and step stored with the spectrum.
- Spectrum images: the sum spectrum, a total-counts map and the full data cube as an HDF5 (EMD) file. Line scans give a CSV with one column per position.
- Tags. The main settings (voltage, magnification, camera length, exposure, stage position) are listed first, followed by every tag in the file, as text and as JSON.
Things to watch
- A DM file can hold several images. The small preview picture that DigitalMicrograph adds is skipped; every real image in the file is converted.
- The picture uses a contrast stretch (or a log scale for diffraction), but the TIFF always keeps the original values, so measure intensities on the TIFF.
- An uncalibrated image (pixel size 1, no unit) gets no scale bar. Enter the pixel size under More options to add one.
Velox users: see Velox EMD to TIFF. To put a bar on SEM pictures, see add a scale bar.
More about what this tool reads and writes: Electron Microscopy File Converter (EMD, DM3, DM4, SER, TIFF).