Six Questions for Frank Rettenbacher

1. What were your initial ideas and goals when you started the collaboration with Thonet?

For me, working with Thonet meant immersing myself in an extraordinary design tradition. I realised from the beginning that the opportunity to work with Thonet was something special and a chance to create something timeless.

My aim was to design a modern, distinctive chair that would fit into Thonet's DNA without appearing nostalgic – and ideally remain in the portfolio for a long time as that is, in my opinion, the best proof of good design.

2. Which aspects of the design brief were most important for you?

The brief was clear: A timeless, functional all-rounder was needed - a stackable four-legged chair that captivates with its simplicity and versatility. A piece of furniture that integrates effortlessly into different living and working environments without being obtrusive. The design had to reflect Thonet’s heritage, but at the same time radiate modernity. 

I was immediately enthusiastic about the task. Ultimately, it was about designing the epitome of a chair, so to speak - a simple chair with moulded wood, 4 tubular steel legs and well thought-out details... a chair with a clear, self-explanatory construction that embodies its function... precisely everything that Thonet stands for as a brand. You rarely get a better brief...

3. How would you describe the feeling of sitting on the S 243 to someone who hasn’t had the chance to try it for themselves? 

I would say that the chair feels exactly as you would expect from a Thonet chair: comfortable and ergonomically designed, ideal for everyday use, whether eating at home, in a restaurant or in a waiting room.

In its simplest form (a version without upholstery), the chair already offers maximum seating comfort. The moulded plywood parts for the seat and backrest are shaped to fit the body: The seat, for example, is slightly wider at the front and tapers off gently at the bottom to avoid pressing into the hollow of the knee. Or the flush-fitting rivets on the backrest, which which cannot be felt when leaning against the chair. In contrast, the frame of the chair conveys stability and lightness. Thanks to its construction with differently sized steel tubes, the S 243 is extremely robust without appearing heavy and ensures visual clarity.

I believe my many years of experience as a designer for Philips TV and audio, where detailing takes place on a much smaller scale, helped me to design the chair with the same precision.

4. Rome wasn’t built in a day – did this saying also ring true for the S 243 design?

The development of the S 243 was an intensive process lasting several years. In dialogue with Thonet, we developed the chair concept with today's flexible living and working environments in mind. As part of the process, we tested countless variations of the tubular steel frame, optimised the ergonomics and perfected the stackability.

One crucial point was the construction: Jean Prouvé had already realised that the greatest load on a chair is on its back legs, as this is where the weight of the upper body rests. That's why I designed the back legs with 25 mm tubular steel - a dimension that can be found throughout the entire Thonet portfolio. The S 43 by Mart Stam served as a reference here, which is also reflected in the name. The front legs, on the other hand, have a slimmer appearance to give the chair an elegant lightness and its own identity.

The colour scheme in combination with the materials was also very important to me: I wanted to create a harmonious palette - classic colours such as black and white, but with a matt lacquer finish and, in contrast, nuanced accent colours such as olive green and tomato red in high gloss. This allows the chair to be either discreetly integrated into the room or used to make a statement. In addition, all colours were chosen to complement each other when stacked.

5. Where would you most like to see the S 243 used in the future?

I think we have succeeded in creating a versatile chair, which can be used in a wide variety of settings. On the one hand, the S 243 has a very homely appearance, a chair that can be used as a classic dining chair or as a colourful individual piece in the bedroom. At the same time, its robustness makes it ideal for public areas: as a café chair, in waiting rooms or in restaurants, where its stackability is a great advantage.

We are currently in the process of expanding the chair family further to cover an even wider range of applications.

6. To what extent did sustainability and longevity play a role in your design process?

For me, sustainability primarily means longevity. A chair is sustainable when it doesn't have to be replaced after a few years, but is used for generations. This is precisely one of Thonet's core values - and something that I really wanted to emphasise in the design of the S 243. Modularity is a key factor here: all components are designed in such a way that they can be easily replaced or repaired. This not only extends the life of the chair, but also underscores Thonet's philosophy of creating furniture for eternity...