Credits: Article and images by Martin Green @ Quill & Pad. See the original article here - https://quillandpad.com/2023/11/05/iwc-portofino-perpetual-calendar-reference-3541-an-oft-forgotten-eternal-gem-reprise/
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Modular madness
The great thing about developing modules is that they can often be applied to different base movements with only a few adjustments. IWC did this as well, and Klaus’ perpetual calendar module was also added to an ETA 2892-A2, turning it into Caliber 37582.
While some purists might complain that such a creation is not as noble as a purpose-developed manufacture movement with a perpetual calendar, the truth is that Caliber 37582 is a very good proposition.
The ETA 2892-A2 is known for its robust construction and precision and it is even relatively thin, making it the perfect engine for the perpetual calendar module.


IWC Portofino Perpetual Calendar Reference 3541
One of the watches in which IWC used this movement is the Portofino Perpetual Calendar Reference 3541, a timepiece that spends much of its time in the shadow of the Da Vinci but offers a cleaner look in a smaller package.
With a diameter of 35 mm it can’t hide its age, but one would be wise not to discard it simply based on this number. Using that 35 mm to its advantage, the Portofino Perpetual knows how to impress.
A case for perpetual beauty
The shape of the gold case is somewhat reminiscent of the Louis Vuitton Tambour, an impression amplified by the crown, which is placed more toward the case back as this is a modular movement. It actually suits the watch, and since the crown is modest in size it does not negatively affect the wearing comfort.


Engraved case back of the IWC Portofino Perpetual Calendar Reference 3541
While the Portofino Perpetual is a true dress watch, IWC doesn’t hide its hallmark technical approach, equipping it with a screw-down case back and crown.
The case is very smooth and remains that way as no calendar correctors had to be fitted. This elevates not only the beauty of the watch, but also makes it very easy to use. As long as you don’t fast forward too much, nothing can happen.


A close look at the dial of the IWC Portofino Perpetual Calendar Reference 3541
The Portofino Perpetual Calendar also offers a few surprises on the dial. IWC made the moon phase disk in aventurine, where its deep blue color and sparkles represent the night sky, while the moon is printed in gold.


IWC Portofino Perpetual Calendar Reference 3541
The dial has a milky shimmer, telling experienced watch collectors all they need to know: it is made of enamel. A closer examination also shows a different finish on the dial and the subdials, which are outlined in gold, providing a subtle difference in height and making the dial very pleasant to look at while enhancing legibility.
Blued hands ensure that there is no guessing what they are pointing to, and despite its smaller diameter the Portofino Perpetual is surprisingly easy to read.
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Credits: Article and images by Martin Green @ Quill & Pad. See the original article here - https://quillandpad.com/2023/11/05/iwc-portofino-perpetual-calendar-reference-3541-an-oft-forgotten-eternal-gem-reprise/