Ever since I began making reproduction German WWII uniforms, I have questioned the use of taupe thread for the top-stitching. It didn’t make sense to me that the Germans would have used anything but matching thread. The only clothing articles I know of that use a contrasting color for the top-stitching are jeans and a few trendy items. I know of no military uniforms that use a contrasting color thread.
So the only answer to this question is that the thread has faded. Even modern cotton threads will fade given enough UV and chemical exposure.
I realize that some uniform makers use the "taupe" thread to give the garment the appearance of wear and age. I think that to be the most accurate, you should start with a tunic that is factory fresh and allow it to wear and fade naturally. This process can be accelerated by laundering and/or allowing the tunic to hang outside in the elements for an extended period of time.
So I don't use taupe thread anymore. I use a modern equivalent of cotton "feldgrau".
I conducted a sun-fading test while I was in Phoenix during July and August of 2007. I tested the modern German wool I use and six different threads: three modern and three original. The wool became greener and the cotton threads faded out to their natural colors, a taupe-like or light beige color. The fading started within one week. Since I was there during monsoon season and it actually rained quite a bit, the test seemed even more realistic. After 4 weeks, the original feldgrau cotton thread was nearly white.
In the photo above, the top set of threads is the Phoenix test after fading for 6 weeks during July and August. The bottom set is the control, which has been protected from light exposure since the beginning of the test. Each type of thread has two stitching lines. Left to right, the threads are:
- ORIGINAL DMC 20 wt cotton labeled as "feldgrau"
- ORIGINAL Anner's 40 wt cotton labeled as "feldgrau"
- modern 16 wt cotton, color is "medium grey"
- modern size 0, 3 cord cotton, color is "medium grey"
- modern 50 wt cotton, color is "green black"
- ORIGINAL Gogginger 30 wt cotton labeled as "feldgrau"
As for the wool itself fading, the blue dye seems to be more susceptible to fading than the yellow and green, so the wool appears to have become more green. (The original German "feldgrau" wool was fiber-dyed with a specified ratio of blue, yellow, and green fibers that were spun into the wool yarns which were then woven into the wool cloth.) I've noticed this same type of fading on original tunics.
Next, I removed some thread from an original M36 tunic that had “taupe” thread. On the stitch loops where the thread was down inside the fabric, where the sun didn't shine on it, the thread was a medium grey.
I also conducted a laundering test and discovered that the thread fades rather quickly when washed with laundry detergent. (I used some wartime original powdered detergent and washed the sample by hand in warm water that was free of any added chemicals.)
I sincerely believe that the Germans never used taupe-colored thread. What we see today is faded, 60-year-old wool and thread that's been exposed to laundering and the elements.
