let's determine how we can get the actual measure of the object on your character of choice to cosplay even if you only got an printed sorce paper. this is usefull in characters with an armour on their shoulders or carrying a sword.
first, you need to write down your hight. lets say you're 6ft tall. i already made a diagram below.

the red box is the hight of the character on the sorce paper(usu from the internet) and the yellow box is the object we wanna get the actual size.
redbox is
divided by your
hight and the
answer is then
multiplied to the
yellow box. isnt that easy?