Using the photograph below I took some measurements; I zoomed in with Windows Photo Gallery to get a more accurate readings.

The tall soldier just under the right side of the flag tarp has shoulder boards which I measured at .375 inches and assuming regulation shoulder boards which are 1.375 inches that gives a multiplier of 3.667. I measured the red stripe over his right shoulder at 1.375 inches and times the multiplier makes the stripe 5 inches, times 13 gives me a flag 65 inches on the hoist.

[Changed the zoom] Assuming the camp flag closest to him is the regulation 18 inches square, the top white stripe is .3125 inches. Each stripe on a 18-inch flag is 1.385 inches thus a multiplier of 4.43. The same stripe, as above, of the tarp flag measured 1.125, times the multiplier gives me a 5-inch stripe and 65-inch flag on the hoist.

Again using regulations, the national colors should be 72 inches and a recruiting flag 52 inches so this one is in the middle. I’m guessing this is just an extra flag and maybe used by a photographer as a prop. But, I haven’t noticed photographs of other regiments using a flag as a tarp or drape. Two of the Irish Brigade photographs are approximately 11 months apart so maybe it’s somewhat unique to them.

I should I thought this all out before the original post. I went from a garrison down to normal size flag; it just looked huge to me and still does. :-)

Ed