The IWC Portofino Automatic 46 is a 46 mm dress watch, and counterfeit examples fail on three points before anything else: case diameter, case thickness, and dial printing. Put calipers on the case and a 10x loupe on the dial before you discuss price. Most replicas sold as 1:1 sit 0.5 mm to 1.5 mm off on size, run thicker through the midcase, and show soft or doubled lettering at magnification.
Prerequisites
- Digital calipers readable to 0.01 mm
- A 10x loupe or a phone macro lens
- Diffused daylight or a 5000K desk lamp
- The published reference data for the exact model number you are holding
- A watchmaker or boutique for a second opinion on the movement
Inspection Steps
- Measure the case diameter across the 9 o'clock to 3 o'clock line, with the crown left out of the reading.
- Measure total thickness from the caseback to the highest point of the crystal.
- Weigh the bare head on a digital scale and compare the number against published specs for that reference.
- Place the watch beside a reference photo shot at the same angle, then compare the bezel slope and lug curve.
- Study the dial text under 10x. Genuine printing has clean edges, even stroke weight, and no ink halo.
- Check each applied index for a polished bevel and level lume fill with no overflow onto the dial.
- Inspect the hands for burrs, uneven plating, and paint that crosses the edge of the leaf shape.
- Advance the date through several days and confirm each numeral sits centered in the window.
- Turn the crown and feel for grit. Check that the crown head carries the correct engraving.
- Read the caseback engraving. Depth should be consistent, the font should match the reference, and spacing should be even.
- Match the serial number and reference number on the caseback against the warranty card and box label.
- Tilt the crystal under a bright light and look for the blue or violet anti-reflective tint that genuine sapphire shows.
Movement and Grade Notes
An open caseback makes the call easier. Genuine IWC automatic calibers beat at 28,800 vibrations per hour, which is 4 Hz. Many replica movements run at 21,600 vph, or 3 Hz, and that difference shows in the sweep of the seconds hand. Check the rotor engraving, the finish on the bridges, and the shape of the balance cock. Clones often use a decorated Asian movement with stamped text that fades under a loupe.
Run a power reserve check. Wind the watch fully, set it down, and note the time it stops. A clone with a short mainspring dies well before the rated figure for the caliber it copies.
Red Flags That End the Deal
- Seller refuses a caliper measurement or a movement photo
- Reference number does not resolve to a 46 mm Portofino case
- Serial and reference mismatch between the caseback and the papers
- Price far under market for a steel or gold model
- Caseback screws that sit proud or show stripped heads
Final Word
Measure first, magnify second, open the caseback third. Those three steps settle most questions about a Portofino Automatic 46 without guesswork.