Using spot-color in LaTeX for print-post-processing

I like to use LaTeX to produce nice looking PDF files for printing. So far that has worked pretty well, but in a recent project I ran into issues, so I want to document the solution here. In some printing jobs, there is post-processing involved e.g. when cutting stickers, when putting gold-foil over certain parts of the design or when embossing. In that case, the files need to follow a certain scheme that this areas can be correctly recognized.

In my use-case, the cut-contour lines of a sheet of stickers needed to be given as a separate colour with a certain name. All solutions that I found, where tailored towards proprietary PDF creators like the Adobe Suite or something in this direction. Even harder, if you search for the german words „Volltonfarbe“ in combination with „Latex“ (or even „LaTeX“), you will end up with results offering to buy latex based paint which is not very helpful. „Volltonfarbe“ in this context translates to „spot-color“ and it is very well possible to use spot colors in a LaTeX document.


Saving 3D Tiff stacks in Python

Reading and writing image data is a recurring task, and I was wondering, why reading and writing image sequences that are saved in one single *.tiff file are not a standard function in the imaging libraries I regularly use (such as OpenCV, libtiff, Pillow etc.).

Reading 3D tiff files is easy, e.g. with OpenCV

import cv2

res_tuple = cv2.imreadmulti(path_to_file, flags = cv2.IMREAD_UNCHANGED)

will do the job. However, when trying to save the resulting array back to a file, it will fail. A working filesave for 3D tiff stacks could e.g. look like this:

from skimage.external import tifffile as tif
import numpy as np

image = np.ones((100,10,10), dtype=np.uint16)
tif.imsave('test.tif', image)

Of course the tifffile library will do that as well, however, I find it more convenient to have only scikit-image installed and let it call the tifffile as external library.

Getting Started with Python + Anaconda + Spyder

In the last few years I have done quite some programming work with Python and started to love both the Anaconda distribution (I might do another blog-post on that topic) and the Spyder IDE. If you are very new to Python and programming, this might be a little overkill, but it will be a very clean basis to start with and no drama, once there is the need to update or upgrade. So follow these steps if you want to get a first quick-start into Python with using the Spyder IDE and Anaconda.


How to get external DLLs into a python package

So, I recently stumbled upon the problem of having to include an external DLL into a python package, which should also work when turned into a windows executable by pyinstaller. This post, is meant to be a help if you run into the same problems I was having (and of course as my personal prosthetic knowledge).

The structure of this post will be: