Kendall and Kylie Jenner display their own creations

NEW YORK— It was quite the family fashion day for Kendall and Kylie Jenner, who came straight from brother-in-law Kanye West's Yeezy show on Roosevelt Island off Manhattan on Wednesday to their own party celebrating their fashion label, KENDALL + KYLIE.

The fashionista sisters (and reality TV stars) said they were gradually becoming more confident designers with each new collection.

"I think that every season we get more and more comfortable," said Kendall, 20, who as a model is a frequent presence on top-designer runways at Fashion Week. "It's super-awesome. The line grows with us."

Added Kylie, 19, also expected to be hitting the runway this week: "We've learned how to work with each other better. I mean, everything down to certain fabrics and patterns. We definitely learned a lot."

The sisters said they've benefited from appearing as models for designers they admire.

"I think it's cool to be able to see both sides," Kendall said. "I get to see the designers that I work with who are obviously on a much higher level than our brand at the moment. It's cool to see their process and what they have to go through behind the scenes, because it's kind of a goal to set and somewhere that I would like to be one day."

At the party, in the multi-tiered, technology-heavy Samsung 837 venue in downtown Manhattan, guests sipped cocktails and munched on hors d'oeuvres as they examined the new collection — heavy on leather, both black and white. Spray-paint artist Malcom Stuart was on hand to decorate T-shirts with his own custom emojis; One could also get a leather backpack monogrammed on the spot.

Many in the crowd had just spent the afternoon in the hot sun at West's marathon, al fresco Yeezy show for Adidas. The Jenner sisters were full of praise.

"It was so awesome," said Kylie. "I love watching his stuff. He's a genius and just seeing his work come to life, it's really cool."