I'm hand writing our inner envelopes. I was going to use a plain black ballpoint, but it looks kind of blah. A gel pen is slightly better. Our invitation is purple, only semi-formal (I made it using clip art, and it's a picture of the moon reflecting on the ocean), and the paper it's on and the envelopes are iridescent. Would it be tacky to write the inner envelopes in a purple gel pen to give it a little pizazz? The outer envelopes will be printed in black ink using a calligraphy font on a printer (jobbed out) if that helps.