Here are the standards for a pyramidal ome-tif file: https://docs.openmicroscopy.org/ome-model/5.6.3/ome-tiff/

These files are supported by the tifffile package in python: https://github.com/cgohlke/tifffile/tree/master

Here is the syntax of opening a specific level of one of these pyramidal ome-tif files from their readme: https://github.com/cgohlke/tifffile/blob/ec6be6289db1b8b7327bb98816a764c95b9b7299/README.rst?plain=1#L678-L682

Here is code to make an ome-tif file to use for testing: https://github.com/cgohlke/tifffile/blob/ec6be6289db1b8b7327bb98816a764c95b9b7299/README.rst?plain=1#L631-L674

I can’t seem to find an easy way to just get the number of layers the file has. A simple solution is here:

simple_all_levels.py

from tifffile import imread, imwrite, TiffFile

f = 'temp.ome.tif'

# Make smaller versions of the big tiff
i = 0
while True:
  image = imread(f, series=0, level=i)
  imwrite(f"L{i}.{f}", image)
  i = i + 1
  print(i)

Just run this until it crashes, the last i that prints is the number of layers. But running until crashing is kinda dumb. After some peeping, I found this snippet:

get_layers_weird.py

from tifffile import imread, imwrite, TiffFile

f = 'temp.ome.tif'

tif = TiffFile(f)

list_of_pages = tif.pages.pages[0].pages.pages

print(len(list_of_pages))

This gets me the answer I want, but getting the length of an array of an accession, of an accession of an array’s first member, which is an accession to the accession of a supplementary import seems too obfuscated to be the intended place for this information to be held.

Where should I look in the ome-tif for its number of levels?