Left: Pentel Pocket Brush Pen sketch on Gutenberg paper with acrylic paint over the sketch. Click on the image to view an enlargement.
Today I wanted to write a little bit about using wet media over your Pentel Pocket Brush Pen (PPBP) sketches.
I've written a ton of posts on this topic because I do this all the time so I have plenty of examples to show you. Some of the images I'm showing today (or giving links to) you've already seen, but I wanted to call your attention to them in the context of the current series of using the PPBP.
Why paint over the brush lines and obscure them once you have gone to the trouble (actually it's no trouble) of working with the brush pen to begin with?
First, some people like to work in pen and ink and I wanted you to know that with the PPBP you can work with wet media over it. You'll want to keep in mind that on various papers the sizing will float any ink for a little bit (and some for a very long time indeed) so if you are going to paint over your PPBP lines, whether or not you want them to still be visible, you need to take the paper you're working on into consideration.
If the concept of how sizing impacts your sketching and use of wet media with ink is new to you please read "It's Not Waterproof until It's Waterproof."
Because papers vary so much I suggested you do your initial PPBP experiments in a Fabriano Venezia journal. I use this brand of journal for my studio journal and it is a great surface to draw on with this pen, but it is also fun to paint on. The ink of the PPBP dries almost immediately on this paper and you're good to go to start painting in watercolor, gouache, or acrylic. I knew you would have the best chance for early experimental success on this paper—and not have to worry about what other factors might be getting in your way.
You can see partially finished gouache paintings that are built up on a base of PPBP lines at this link. My goal there was to use the gouache to completely cover the lines. The lines were only meant to be a "skeleton" or guide for my later painting.
Often when I set out to do this type of work I fall in love with the lines on the paper and don't want to cover them with paint. If this happens to you consider working in transparent watercolor and retaining your lines. Alternately you can simply take a photograph or scan of your original line art before you dive in with the paint.
Over time, I do encourage you to dive in with opaque wet media just because it is so much fun, but also because it's good to let go of our line drawings sometimes. We can always make more! It's a good way to get over being precious about your work.
Painting with opaque media over you brush pen lines will also free your sketching up. You will come to understand that you can "correct" or adjust even the most awkward of bold ink lines you might have placed on your page. You'll sketch more boldly knowing you can go to paint. It gives you more options.
Today's Project
For this weekend, or week if you can, I'd like you to keep making your sketches, but to keep in mind that you will be painting over the sketch when you are done. Do this with watercolor, gouache, or acrylic—whatever you are comfortable with.
Here are some questions to keep in mind as you work, and some exercises:
1. Think "Which lines can I leave out because I'm going to come back in and add painted areas?" Review my comments about the gargoyle sketch at the bottom of Part 3 in this series. In that image you'll see areas of watercolor which I repeatedly darkened to create shading, areas not enclosed by pen lines.
2. Review the image I painted of the angry woman in the first post of this series. You'll see that I'm not trying to add any shading lines (crosshatching or squiggles) in that sketch at all. I have some pen lines indicating segments of strands of hair, but all the other lines in this image are simply the edges of features I wanted to be hard. I have only the thinest suggestion of a partial ink line of the cheekline to the ear, because I knew I was going to add paint there in shading. I could have scaled back even more in my lines, omitting the lines under her eyes for instance, but I really wanted the hard edge there to accentuate that she was wrinkled. As you sketch, when you know you are going to use transparent washes, plan what you can leave out. One of the bits I think works best in this sketch is the left side (our left) of her nose, where there is no line down to the lip, but only color for shadows.
3. Experiment with simply stroking color over the pen lines as I did in this dog sketch, and then adding some additional shading with light washes. Note the lips on this dog, how I bring the shadow up around the lip. It would be too "strident" to have pen lines shading here, so instead, knowing that I'm going to paint, I omit any lines there and make the paint do the work. I am suggesting you broadly stroke color over your pen lines in random ways because it's fun and you can have the experience just playing with the paint and seeing how the lines stay put. You could of course work with the PPBP on a pre-painted page. The bold lines the pen makes totally hold their own on a variety of backgrounds.

Left: Here's a page in my blue paper journal where I worked in PPBP and then went over the image with some basic gouache layers, just to add a couple more layers of value and to test how white the white would appear (too white with this range of values, but that's why I experiment). The background was painted in to obscure a previous sketch that wasn't working and to isolate the head. Click on the image to view an enlargement.
4. Experiment with toned papers. You can pre-paint your pages first with acrylic inks or diluted acrylic paints (you want your paints diluted enough so that you don't have an acrylic film on your page which will repell the ink of your PPBP). As you've seen in recent posts from the blue-paper journal the PPBP can stand on its own on even a dark surface, but it's also really fun to paint over the lines and have the color cover the ink.
5. Make your line drawing simple and then add only shadows with transparent washes. This is a good way to get familiar with adding paint to your sketches. Do several sketches like this in rapid succession, pausing only to use a different color for shading. At the end of your session look over your pieces and decide which cool temperature color mixes you like for shadow work. From those colors you can work up an entire mini-palette of colors with which to do more finished pieces. You'll find triads and complementary pairs that you enjoy working in; color families you can't live without.
6. Experiment with other media such as watersoluble pastels. I do a lot of sketches with the PPBP which I then cover with StabiloTones or NeoColor IIs. You can find my method by looking under "StabiloTones" and "colored pencils" in the search engine for this blog. There are tons of examples of what I do with these items.

Left: A sketch of a bantam that you've seen on the blog before. I started with a PPBP sketch and then worked up layers of StabiloTone over the ink lines. Very few of the internal ink lines are left visible, but I do allow the black lines to appear at any edges where I need crisp contrast because I typically don't use black pigment. This is in a journal I made with Gutenberg paper. Click on the image to view an enlargement.
7. Experiment with a variety of brushes on a favorite wet media paper. You want to use a paper you enjoy working on with wet media. Then you want to make your sketch with your brain editing back the lines that you put down because you know you are going to add paint. Then when you go in with paint use brushes that you normally don't use. If you always use rounds, use a flat. If you never use a fan, pick one up. The idea is to do broad washes, not fussy ones. Mix your value on your palette and hit it with one line (see the first link example of the lab image in the next exercise). Broad bold brush strokes that define form and provide local color and shadow but don't necessarily "stay within the lines" work great with the boldness of the crisp ink line the PPBP provides.
8. Experiment on a variety of paper types. In this PPBP sketch of a lab on Stonehenge you can see I've added a little bit of color. While I enjoy painting on Stonehenge it is a printmaking paper and not a watercolor paper. It might not be a paper that suits every watercolorist. Gather a selection of papers on which you enjoy working. If you've already done the experiments suggested in Part 4 of this series you've already gathered and tested some papers with your PPBP. Now you'll be testing your favorite wet media on those papers, over the PPBP lines. Make a sketch and immediately go to paint over it. Do the lines bleed at all on the paper? A lot? A little? Only in certain areas? If the ink bleeds at all set the drawing aside for a couple minutes and keep coming back to it to test the lines with a clean wet brush every 2 minutes or so. In that way you'll discover how long it takes for the ink to dry on that paper. Two minutes? Ten minutes? Longer? What is acceptable to you? For me, because I sketch quickly and want to go to watercolor or gouache immediately I need papers that absorb the inks I use quickly. As you read in the "waterproof" post I provided a link to earlier, some of our favorite papers may change from batch to batch. And some may have idiocyncracies with which you can live. You'll only find this out by doing these experiments, working the way you want to work, in the conditions you typically work in (e.g., a dry environment, a humid environment, etc.).
That's quite a lot of experiments for a weekend or a week, so I know this will be something that you can come back to over time. What I would encourage you to do is to try your favorite wet media with the PPBP for several days in a row before switching to a different wet media (or watersoluble media). Spend a good hour or more each day for 5 or more days just focusing on how you can best use the PPBP with that favorite media before you go off to explore another wet media with it. You want to see what you can do with a medium before you move to the next one.
In this way you will develop a familiarity with your tools and media.
Have fun with the Pentel Pocket Brush Pen. I'm sure I'll have more to say about it.
I had hoped several weeks ago to make a video of me sketching with it doing some of the things I have been writing about. It just wasn't possible. But I still have plans to do that and will keep you posted. In the meantime keep working with that pen!