I have a pattern for some beautiful slippers that call for double knitting. Now do I HAVE to use dn yarn weight or can I use a heavier weight yarn and NOT double knit? :shrug: Thank you for any help! 
I have a question about double knit
Are you talking about double-knitting as a method to create two layers of fabric? In that case, you can use any yarn you want! For some reason (and I understand this is common), your tension can come out a bit looser when double-knitting so you may find that you need slightly smaller needles than you usually would when doing regular knitting.
If you’re talking about double knitting yarn – as in, a yarn of a certain weight somewhere between fingering and worsted (“DK weight”)-- sure you can use a heavier yarn, but you’ll have to adjust your pattern to accommodate the different gauge.
Gee, you have asked me a good question. Here is what the directions say for the slippers…
Materials: For women’s size: Double knitting (DK) pure new wool, 1 3/4 oz balls.
Just by reading that I still can’t tell if its the yarn or the method. What do you think? The slippers do not look thick. Looks more like a worsted weight yarn to me…but I really can’t tell.
The book is Knit handmade style by Janine Flew. There are beautiful blue and white slippers in this book and thats the reason why I recently purchased tthe book.
If you see the link below and click on the picture of the book they even show the pretty slippers there in blue and white.
http://www.knitpicks.com/books/itemid_30907/books_display#
Thanks again for any clarification you can give me.
It’s DK wool not double knitting.
Thanks so much!! I’m still learning.
Yup. Unless you have your mind set on a different yarn, look for a DK weight yarn. It’ll be a little lighter than worsted.
I have no answer to your question but I love many items in the book! I just ordered it. Thanks for posting! 
You’re welcome!