Here we have a poorly lit photo of two swatches, in identical yarn (Elann Peruvian Baby Lace Merino - 50% baby alpaca, 50% merino), in identical pattern (the test swatch for Susan Reishaus' Mystery Lace - 21 sts wide, 20 rows), but using two different sizes of needles. This is several days after blocking, so they've relaxed quite a bit. They were actually identical sizes (3 inches tall, 3.5 inches wide) on the blocking board. Alpaca doesn't block the same way pure merino does, that's for sure!
The one on the left is knit on size 3 needles, and blocked very VERY hard, as you can see by the zig-zag edges where the pins went in. Below is a larger pic of it, with the yarn almost true to color. It's actually a bit dustier IRL. To my personal taste, the pattern is just a hair too sqooshed in, too "solid" looking. Even under the very hard blocking, the design definition is somewhat lost, and the leaves on the sides are very blobby looking.
Here is the exact same swatch, but knit on size 4 needles. See how the leaves have opened out, and the entire design is just a bit "airier"? I like this better, and it's the way I'm going to go. I'm almost tempted to try it on size 5 needles, before I actually cast on, part one of the actual stole having been released, but I probably won't.
BTW, I told you, a few posts back, that you would be seeing more of this yarn. Yep, it's the "waste" yarn I used to hold the stitches on the sock. I have a tendency to use waaaay more yarn than I need to do the long-tail cast-on. It also becomes stitch and row markers, so not actually wasted.
There's another mystery shawl KAL coming up, the "Slo-Bee", to be Faroese shaping, which I really like, that requires almost 3,000 yards of yarn. OUCH on the yarn budget! There will be much lace knitting going on here for a while. I'm going to have to finish up a couple of those needlework projects that have been languishing at the bottom of the WIP basket, if only for a bit of mental relief from the intense concentration the lace requires.