NEW YORK — New York Fashion Week marks the beginning of a long, multicity, international jaunt that moves on to London, Milan and finally Paris, the city whose fashion week won’t end until early October. As the last footfalls faded from Marc Jacobs’ week-closing runway show at the Park Avenue Armory, it was all but impossible not to feel optimistic.

That’s because the collections that came down the runways here Sept. 5-12 were filled with feel-good fashion — bright, vivid colors, playful patterns and laid-back luxe that didn’t take itself too seriously. It’s all an antidote to the dour state of affairs beyond the runway. Here are several big trends that kindled that infectious, feel-good feeling and will be heading to stores six months from now.

Peppy polka dots

You’d be hard-pressed to find a pattern as playful as the old-school polka dot. German brand Escada, which made its New York Fashion Week debut with a 40th anniversary horse-racing-themed collection that riffed on jockey silks. At Carolina Herrera, Wes Gordon made his runway debut for the brand by showing an upbeat pattern-filled collection that included florals, stripes and polka dots.

Another NYFW debut, that of Los Angeles-based designer Rebecca de Ravenel, popped with polka dots.

Her garden-party-themed presentation on the terrace of the Gramercy Park Hotel served up summery polka-dotted dresses.

Lacy overthings

De Ravenel’s garden of terrace delights was abloom with one of the season’s most noticeable fabrication trends — delicate French lace and eyelet lace.

Tom Ford’s spring and summer collection made use of French lace by layering heavy leather jackets over wispy, lingerie-like tops and georgette skirts and to trim dresses, which gave the collection a soft, feminine feel.

De Ravenel’s collection focused on eyelet lace, using a repeating daisy-like shape to create easy-breezy dresses that resembled fields of scattered flowers.

The look would be perfect for a Southern California bride’s garden wedding.

The beachy keen Michael Kors Collection served up a range of pieces in white cotton eyelet lace including ruffled dresses and a bikini.

Rodarte, the Southern California label, returned to the NYFW lineup with a memorable collection of ultra-feminine dresses filled with frills, bows, ruffles, tulle and lots and lots of lace, some in pale pastel shades and others in vibrant hues of blue or pink.

One of the most striking looks was a tiered, color-blocked ruffle dress that included at least a half-dozen different colors of lace.

Peak pink

The big color story coming out of these runway shows was an emphasis on sunny yellows and grassy greens with the trickle of pink that started at the February shows turning into a full-on hurricane of hues ranging from dusty rose to neon pink with stops at shades such as watermelon, bubblegum and flamingo.

Memorable members of the week’s think-pink posse included Brandon Maxwell, whose Texas runway show featured popped-collar shift dresses, wide-legged trousers and pleated minidresses in bubblegum pink; a clingy, one-shouldered gown in dusty rose; and a shirt-dress with Western-inspired silver hardware in a shade approximating salmon.

Then there was Marc Jacobs, whose panoply of pink pieces included voluminous pink silk trousers, enormous ruffled tops and dresses, wide-shouldered suits and a cocoon-like, ostrich-feather-festooned dress in flamingo pink.

Prabal Gurung, a designer whose embrace of the color last season made for a memorable collection, had plenty of pink on the runway this week as well.

His presentation included vibrant pink rib-knit tank tops and pastel pink suits for the men (spring and summer 2019 marks the label’s debut menswear collection) and cargo pants and bikini tops for women.

New kids on the (color) block

What really made Gurung’s latest runway collection stand out — and remain on-trend — was his liberal use of color blocking such as a lemon yellow rib-knit bodysuit with fuchsia-tipped sleeves paired with a peridot green silk-chiffon skirt trimmed in fuchsia silk; and a blue, white and yellow ombre cashmere hoodie paired with indigo denim jodhpur pants embellished with ostrich feathers.

Other labels sending bold color-blocked pieces down the runway included Carolina Herrera, who, like Rodarte, served up a particularly eye-catching piece in color-blocked lace, and Escada, where global design director Niall Sloan paired pink (on the right side) and black (on the left) in a silk, pajama-like top; and blue and green in a color-blocked silk shirtdress.

Using large geometric areas of contrasting color in a single garment is nothing new (see Yves Saint Laurent’s 1965 collection of Mondrian-inspired cocktail dresses).

Stacey Bendet, creative director of the Alice + Olivia label who had several color-blocked pieces in her brightly colored spring and summer presentation, had a practical explanation for the season’s color-blocking boom — as well as the embrace of bold color overall.

“I think Instagram has created a year-round color sensation,” Bendet said. “Neons, brights, color blocking — things that look no-brainer beautiful in a picture. It’s really influenced the way I think about designing. I think (the demand for) neon was really developed from Instagram. Everyone thought neon looked so cool in photos, and people just kept wanting more of it. The same with that color blocking. Every time I do a sort of rainbow color-blocked dress, it’s all over the internet.”