A resume counselor advised sending US Mail resumes in a large envelope. I interpreted this as a 9 x 12 in which the resume is not folded. However, this is usually brown kraft paper, which is OK but not all that nice. On the other hand, we are taking the trouble to use a nice resume paper (I used off-white, ivory ). Do we not want to use the matching envelope, even though it is a number 10 envelope (4 -1/8 x 9-1/2 )?
I agree with the resume counselor who said you should use the 9x12 envelope so your resume will not be folded. The reason: the print on the resume can crack if the fold happens on a line of print. And if that resume is photocopied by the employer, there will be one or two lines with crummy print and no fold to explain the poor quality. The way to avoid this problem is to send the hardcopy resume flat in a large envelope.
The color of the envelope doesn't matter. It will be opened by an office clerk or administrative assistant who will promptly throw the envelope away and pass your resume and cover letter on to the appropriate person. But if the brown envelope bothers you, you can use a white 9x12 that will look quite handsome.
By the way, it's perfectly fine to hand-write the address on the large envelope, as they're too big to fit into most printers.