i've heard the same. i say don't risk it. if you have a choice of buying already black lace, i would do that. you can try with the other lace, but it would be easier to just buy lace that is already the color you want
I love lace. It is elegant and feminine. My wedding gown had a lace skirt and lace on the sleeves, and I wore a lace veil. It depends on where you wear the lace. It doesn't have to be scratchy. I have an all lace dress, I wore for my daughter's weddi...
When you say "good quality mantillas", do you mean the super intricate lace throughout the whole veil, rather than just around the edges like this one: ? Here are some that are closer to what you pictured, for a bit cheaper: Good luck!