Why Do Brand-New T-Shirts Have That Vintage Look? The Magic Called "SP Processing" Crafted by REMI RELIEF

What makes vintage T-shirts so appealing is their faded colors and textured fabric from years of wear—but finding one in just the right condition and size is almost impossible.

This is where the REMI RELIEF "SP Processed Tee" deserves attention.

Since they're brand new, you can pick your favorite modern silhouette and ideal fit—plus, the fabrics carry that perfectly worn-in appearance and soft feel you'd find in true vintage pieces.

To uncover the secret behind it all, we spoke with designer Yutaka Goto.

It All Started with Understanding How Vintage Fading Happens

REMI RELIEF is a Japanese label known for recreating the look of American vintage through its unique methods. The "SP Processed Tee" is one of their signature pieces.

The development began in response to a BEAMS buyer's request, "I want a sweatshirt that feels genuinely vintage." Goto investigated the true mechanism behind vintage appeal to artificially recreate these traits.

"Cotton is mainly made from a natural fiber called cellulose, but the dyes we use to color it are synthetic chemicals. So, something like an adhesive is needed to attach them.

"What acts as this adhesive is an enzyme called cellulase, and the color is fixed using an amino acid-based glue known as a fixer."

In short, when cellulose, cellulase, and amino acids react with heat and oxygen, a chemical reaction called oxygen bonding occurs, which colors the cotton fabric.

Simulating Real Aging by Reacting with High Heat & Hydrogen

So, how does that lived-in, faded look of vintage clothing actually happen?

"Oxygen in the air is deeply involved in fading. Oxygen reacts with the cellulose in cotton, and when combined with heat from sunlight, oxygen bonds to the amino acids in cellulase. This oxidizing bond triggers hydrolysis, slowly breaking down the dye and giving it that beautifully distressed appearance.

"Picture hydrogen in the air subtly working its way into the dye’s adhesive (cellulase), gradually loosening the dye and causing subtle color loss over time."

To replicate this vintage fading artificially and in a short time, a special processing tank—a closely guarded part of the process—is key.

"In a typical environment, even during summer, the temperature is about 35°C and the oxygen concentration in the air is only around 32%. So, to accelerate processing, we raise the kettle temperature to about four times a normal summer day, around 120°C, and at the same time use hydrogen to push the oxygen concentration inside the kettle up to almost 98%. By doing this, oxidation bonding accelerates rapidly, and based on the hypothesis that we can recreate about 5-10 years' worth of aging, we've taken on this challenge."

In just about 10 hours, it's possible to replicate the vintage look and feel. It's truly like a time machine for creating vintage wear.

Using Dyes Found in Clothing Made Before 1975

The key to getting those unique vintage tones lies in the dye.

"I personally love vintage wear from the 1930s up through the late 1960s, and after years of collecting and wearing them, I noticed something.

"Back then, sweatshirts and T-shirts mainly used direct dyes (dyes that dissolve in water and directly dye the fibers) and sulfur dyes (dyes containing sulfur atoms). However, around 1975, there was a distinct shift as if by agreement, and brands started switching to reactive dyes (dyes that chemically react with the fiber).

"That's because the newer reactive dyes were developed to keep pace with the mass production era of the 1970s and beyond. Direct dyes and sulfur dyes, on the other hand, are harder to manage—prone to fading and color transfer—so they aren't suitable for mass production."

Reactive dyes have several advantages: they barely fade in the wash and are highly colorfast. But Goto is especially captivated by the colors unique to direct and sulfur dyes.

"The reactive dyes widely used today are generally blended from three primary colors (red, green, blue) or four primaries (red, black, white, blue) to produce a range of shades. Each dye has its own dyeing property, or 'dye foot' (how fast or deep the dye penetrates the fiber). So with three primaries, you have three different dye feet; with four, four types.

"Because each dye foot bonds to fibers at a different strength, even under the same conditions, the speed at which each color fades can differ.

"This means vintage clothes dyed with reactive dyes from after 1975 often display significant color shifts as they age—reds stand out, blues emerge, and overall colors can shift dramatically due to differences in dye foot fading rates.

"On the other hand, pre-1975 vintage, what we call true vintage, used direct or sulfur dyes. Direct dyes also use three primary colors, but compared to the strong chemical bonds of reactive dyes, their dye feet are weaker, so multiple dyes tend to fade at the same rate.

"And since sulfur dyes are made from a single color, there's only one dye foot. This nature means that with vintage items dyed with direct or sulfur dyes, all the dye fades simultaneously, creating a natural contrast with the original fabric color.

"This is the crucial point—the fading looks cleaner and more refined."

To recreate Goto’s ideal vintage fade, sweatshirts and T-shirts are dyed with the same direct and sulfur dyes traditionally used in the past.

"SP Processing is a vintage treatment technique using a chemical reaction of heat and oxygen to fade old-style dyes. Unlike chemical or bio-processing, which dissolve the fabric, this method recreates more authentic, aged, vintage looks."

To achieve the ideal fade, REMI RELIEF established its own in-house factory.

"Usually, when applying vintage processing to clothing, most brands outsource it to specialized factories. But SP Processing requires long hours—about 10 to 12 hours in the kettle—and precise control over temperature and humidity. Outsourcing would make it too burdensome for the factory and costs would skyrocket.

"So, in 2008, we set up a factory in Kojima, Okayama Prefecture, where we handle everything from sewing to dyeing to processing in-house. For a brand our size to process vintage treatments in-house is almost unheard of."

"When I first showed our original sweatshirt to a buyer from BEAMS, they loved it and we went straight into production. After launch, the response exceeded even our expectations, so we decided to make T-shirts as well and launched the SP Processing Tee in spring/summer 2009."

They even prepared a new kettle specifically for T-shirt production.

"When clothing spins and drops down inside the kettle, the larger the kettle, the greater the damage to the garment. So we had a manufacturer custom-make a kettle just the right size for lightweight T-shirts."

There’s a reason why stones are placed inside the drum during processing.

"The use of stones makes it easier for the oxidized, carbonized dye to detach from the fabric. To prevent damaging the clothing, we use smooth, rounded stones. These are custom-made to specific sizes to match our needs.”

Jersey Fabric Knitted with American Cotton Open-end Yarn

Even for the main T-shirt body, materials that work well with SP processing are carefully chosen.

"We use fabric made from No. 30 count American cotton open-end yarn. Open-end yarn refers to fibers twisted together using air, which results in yarns with just the right amount of air between fibers—one of open-end yarn’s distinct features.”

The jersey fabric, knit densely with fine yarns, remains lightweight but has a firm structure, making it comfortable and breezy even in summer.

"I believe the unique texture also depends on the humidity where the yarn is spun. If spun in Japan, the yarn absorbs moisture and feels damp, but in America’s dry climate, it naturally develops a light, crisp touch.”

All the graphics are personally designed by Goto.

"The reason graphics on vintage T-shirts have such appeal is because most of the original designs are hand-drawn—there are rarely any perfectly straight lines. Nowadays, I use a computer, but I take my time to carefully recreate that hand-drawn look.”

Special pigments are also used for printing.

"We use pigments whose particles are purposely uneven. That way, after processing, the pigments flake off naturally, creating a look as if you’ve been wearing the shirt for about half a year.”

T-Shirts that Evolve With Their Owners

The golden rule for making SP processed T-shirts is “80% processing.”

"I honestly don’t think T-shirts are meant to be worn stiffly or with too much formality. The ones you’ll reach for every day have just the right amount of lived-in feel and great atmosphere—that’s what makes vintage T-shirts so charming.

"Plus, for adults seeking an easy-going look, it’s best not to overdo the processing.

"That’s why we keep the processing dialed to about 80%. I want the remaining 20% to develop as you wear it—letting each person finish the story of their own shirt.”

The name for the processing is derived from “Special.” As the name implies, the SP Processed Tee is a unique T-shirt that only REMI RELIEF can create.