The two main issues one confronts when determining what to use to sign a matte or semi-gloss print are longevity and ability to hold onto the surface of a particular paper. For matte prints, such as pigment inkjet prints on rag watercolor papers, I prefer to use mechanical pencils (usually with a .7mm point) because like most graphite pencils, they offer great fade-resistance, as well as a consistently sharp and easy to control point. One in particular, the PaperMate ComfortMate Ultra .7mm mechanical pencil, is a favorite because of the way the pencil lead sits securely inside the barrel and because of the soft rubber hourglass-shaped bottom section.
There is a technical term called “Pencil Lead Degree,” which denotes the hardness of the lead (which is not lead at all-it’s actually graphite mixed with clay). (#2) is a very common pencil lead degree (also called “tone”) widely used in the United States, and a classic #2 pencil is a good example of what you can expect from mechanical pencils with the (#2) rating. If you search for a mechanical pencil online or on the manufacturer’s site, you should be able to determine what the tone of it is from reading its specs. A (#1) pencil has a darker tone than a (#2), and a (#3) pencil is lighter in tone than a (#2).
In most parts of the world outside the United States, a different system is used. For example, HB is equivalent to the US (#2) lead degree. That’s why you will often see “2-HB” or “HB #2” as the tone when looking at pencil specs (it’s denoting the US and international systems). A very good history and overview of pencils (including grading charts) –can be found here: (some of the information here was sourced from this page).
For glossy and semi-gloss papers such as traditional C-prints and fiber-gloss inkjet papers, I spent a lot of time searching for just the right pen because pencil graphite just won’t hold onto the vast majority of these surfaces. My current favorite is the Sakura Pigma Micron Pen (Black). There are many different point sizes available, from ultra-thin (005 = 0.20mm) to quite thick (08 = 0.50mm). These pens have an outstanding reputation for permanence, and another great feature is that they dry quickly on most surfaces, which is especially good for left-handed people, as well as authors and others who sign books. It’s nice to know that there won’t be rub-off on the opposite page, especially if you wait just a few seconds before closing the book.
See the photo above for examples of how 5 different Sakura Pigma Micron Pens look on a fiber semi-gloss inkjet paper (Ilford Galerie Gold Fibre Silk). For most prints, I’m currently using the (01 = .25 Sakura Pigma Micron), and for book signings, I generally use the (03 = .35) or (04 = .45) because those pens produce a stronger, thicker line, and they hold up better in heavy use because they have a stronger tip. That being said, thinner point sizes will appear less dark in situations when you want to emulate the look of thin pencil.
To find the pens online, just search for “Sakura Pigma Micron.” They are also sold at many arts and crafts stores in the United States, including Michaels. They come in a range of colors, and though I’ve only used their black pens to date, if I needed fade-resistant color pens, I would strongly consider using theirs.