Another older thread that has great interest for me.
I generally agree with cuprum on the broad strokes (i.e. that the colors were normally kept in the rear for much of the war), but I do feel they were carried in the front lines in 1914 and during any subsequent Russian offensives in the later years. The practice of keeping them in the rear, I believe began sometime in late 1915 when trench warfare fully settled in on the Eastern front. The truth of something like this is difficult to demonstrate as photographic evidence during actual combat (not the staged stuff) is rare.
In my Courier article on the RJW flags, I found several accounts by military observers that stated the colors were carried cased into combat and a few more from less reliable sources stated they were sometimes uncased. I believe this practice was continued in WW1, given the absence of any record to the contrary.
I agree with cuprum in his statement in the linked thread below that colors could have been carried uncased. This would be a regimental-level decision and commanders are often proud of their units and see the colors as a unifying/motivational tool.
https://leadadventureforum.com/index.php?topic=128333.0In my search for some evidence, I did find this photo of a Russian regimental color in the trenches in Washburn's
Field notes from the Russian Front, p.256. It is in his chapter 'A Visit to the Trenches' and is dated January 1915.
v/r Jeff