Pad printing at TecaPrint, continued.

One of the largest challenges with ultra high quality pad printing is the tension between two important characteristics - clarity, and depth.  Both of these characteristics are technical challenges in and of themselves, and we tackled each in our training at TecaPrint last week. Clarity is driven primarily by three main factors, ink choice, silicone pad choice, and the "cliche", or in english, the template.  Depth, on the other hand is mainly driven by the ink choice, drying time, and the amount of reprints, or restrikes onto the dial. Earlier this week, we wrote about ink and pad selection, but today we will talk about the "cliche". The cliche is foundational to a good quality, clear print. A poorly made cliche, with errors in the graphic will always produce poor results, no matter how good the pad and the inks are. Alternatively, a high quality cliche will provide crisp text, thin lines, and will enable you to reproduce the finest details onto the dial - the foundation for clarity.

Depth in pad printing is incredibly desirable from a watchmakers perspective. It is a sign of true quality, as depth can only be achieved when all the parameters of pad printing are perfectly tuned. It is also a sign of restraint. Depth is slowly created by layering paint on top of itself by printing the same pattern multiple times. Obviously you can do this for eternity and have as much depth as you like! The trade off is clarity. At one point the print becomes messy, thick, floppy and fuzzy. All the clarity you gained by having a fantastic cliche, great inks and a perfect silicone pad is ruined by just printing one too many times! Sometimes the difference between clear, voluminous print, and a "bloated" print is just one hit. Knowing where that line is and sticking below it shows a mastery of the entire process.

One of my favourite stories from my time at TecaPrint came from my tour of their in-house cliche manufacturing lab. Cliches are usually made of hardened steel and have a pattern etched, engraved or lasered into them. The pattern is only 18-25um deep, and must be extremely tightly controlled so that the ink that is trapped in the relief is picked up by the pad without any distortion of the image.  TecaPrint uses a very special process to acid-etch steel plates with the image. Whether it be a simple cliche with just the name of a company, or a complex graphic, like the minute track of a watch dial, with many lines, shapes, dots, text and markers. Macedonian born Mite, the head of the cliche manufacturing department, is in charge of making these plates. First the plates are lapped to a mirror finish, and polished so they are totally scratch free and dead flat. The type of steel that is used is also critical to ensure a long life of the cliche, but understandably, I have to remain tight lipped about that! After lapping, the plates are coated with a photo-resistive film which is then exposed in a monochromatic light cabinet to reveal the image onto the film that covers the plate.

The film is then developed and "hardened" in a chemical bath. Once hardened the exposed areas of the film are washed away, revealing the raw surface of the plate.  The whole plate is then placed in an acid bath which slowly etches only those areas that do not have the protective film. This is tightly controlled so that the etched image is approximately 20um deep. Any deeper and the amount of ink that is pushed into the relief is too great, and any lighter and the pad will struggle to pick up enough ink to transfer properly. One extremely important step, and Mite's specialty, occurs after the hardening process, and before the etching process. This process is called the "retouching phase" and involves skilful hand work under a powerful microscope. The image that is about to be etched in the next stage often has small errors. Either areas that are not properly formed, or little dots that look like "noise" in the pad. Mite spends up to 3 hours under the microscope hand painting the errors out in the image. A flawless cliche is thanks to TecaPrint's stable and well tuned etching process, but equally Mite's steady hand and 19 years of experience hand-correcting cliches!

Mite was really lovely. He spent the better part of an hour explaining everything in the lab, and you could instantly see that he was truly passionate about his job. "I love this - seeing the image come to life, knowing that my hand had a little part to play in the process is so exciting". As I was leaving the lab I turn around and thank Mite for his time. I can't help but see something in the corner of my eye. I point to the wall, a Rolex calendar is hanging just above his microscope. "Lovely dials, don't you think?!" Mite shrugs, and with a smile on his face points to a batch of cliches that are waiting for his magic touch.  "Every year Rolex sends me a calendar. It's a small gesture, but it makes my job of working on all these new models so much more satisfying" My heart drops as I realise who is standing before me... Yes there are designers, and engineers, and technicians and watchmakers that make that crown-marked-watch, but Mite, a veteran of nearly two decades has been the final stage of QC for every single cliche for every single pad printed Rolex watch in the better part of the 21st century. And here, the same man that painted the minute-track pad printing cliche for the latest Submariner, hands me the MK2 pad printing cliche for our minute track... "Enjoy" he says, "Thank you for visiting my lab, and not just sending a calendar!" No, thank YOU, Mite!