How to color with an even darkness?
The issue is half medium, half technique.

First, your medium. You need something with high opacity. In wet media, we're talking black ink, and probably a wet one. Examples of Black inks which can be easily manipulated to produce an even distribution are sharpie markers, India ink, the proprietary uni-ball brand's ink pens, and Copic markers of the darkest black. For dry media, you want something soft and easily blended, with a really dark color. You want charcoal, or the softest B graphite you can find. I have found that eyeliner pens also work, as weird as that sounds. I'll talk about watercolor pencils at the very end. In either case, even the best tool is not enough. A mark which shows no hand in its production is a very difficult thing to create in traditional drawing media. My own college level instructors told me it was so difficult, it wasn't even worth chasing. (I disagree with them. Mastery of material and technique is always worth pursuing.) It is much easier in painting and printmaking techniques. Doing it with drawing media just takes practice and patience, but using the right tools for the task will make it easier. Black is always the best choice in this regard, as it is usually the most opaque pigment on any palette. The more translucent the pigment is, the harder this becomes.

The technique:

Keep in mind, this technique takes a long time to practice and master. It requires a ton of patience and endurance. It is a meditative task, in that it is slow, repetitive, boring, and more than a little uncomfortable. It is a trial of tolerance, and demanding of a quieted but focused mind. I would not do this in a place where you are likely to be distracted. Learning this technique is how I learned what it means to meditate.

1. Be gentle:
Press just hard enough to apply the pigment, and absolutely no harder. The weight of the tool alone should be more than enough. Most of an artist's hand is exposed by the damage it does to the paper. By preserving the finish of the paper, you hide your mark. Love your paper: that original finish is why you are doing this in the first place, after all!

2. Go slow:
This is especially important with inks, but just as important with dry media. Go just fast enough to leave your mark. Going too fast will pull at the texture of the paper laterally, changing the way light reflects off of it. With ink, you still need to keep a decent pace; the slower you go, the more ink soaks into the page, and the more it bleeds outward. If you're using ink, draw from where you know your bled edge will be, not where the edge of your nib is. Having a really tightly packed paper, something machine-pressed, with poor absorption, is a good thing here, as more ink will sit on the surface, making the mark take longer to dry, and getting you a darker result. For dry media, you'll want something stiff and toothy, something that can carve out your marking tool like sand paper. You won't always get to choose the best paper for the job, but if you have the choice to use the best, then you should make the choice to use the best.

3. Full length strokes:
In even, straight lines, at a constant pace, scan from one edge of the shape to the other. Do not break this line until you arrive at the opposite edge. Be careful to make the ends of each mark flush with the edges of your shape. The ends of a mark have subtle differences due to minute changes in pressure and timing as your physical hand changes direction. You want to "hide" these subtle marks by putting them in the edges of your shape. If you make the mistake of coloring a large shape in "blocks", then the mark ends line up and the series of subtle marks become a visible line of their own. If you color at random, the many marks form a texture which telegraphs your hand to the audience. So, while it is painfully slow, color it one line at a time, scanning back and forth like a computer printer. Your hand will cramp. Adjust your grip slightly with each mark to delay and reduce discomfort. If you are using dry media, you can rest your hand every few marks, but ink is far, far less forgiving.

4. Overlap:
Each mark you make, make sure you overlap the previous mark by slightly more than 50%. The thicker your mark, the easier this is to do. This is especially important with ink, as the repeated overlap ensures maximum deposition of ink at the surface, helping to hide the effects of drying time differences from one mark to the next. This is why ink is so much less forgiving. You want to finish each mark before the previous one has finished drying. The faster the ink dries, the harder this becomes without damaging the paper. Slower drying inks, like dip inks, are often preferred. This urgency imposed by the drying time for inks makes this technique rather stressful if you are not comfortable with the ink and paper yet. Reactivating inks, (like copics) which begin bleeding again when exposed to their wet medium, are a very good option, because the overlapping marks will bleed together somewhat, reducing the need of good mark timing.

5. Two coats:
Go over the work a second time, angling the strokes of the second coat by about 30°. Be even more gentle than the first pass, as you have already weakened the paper's finish. Ink will have significantly altered the absorption rate of the paper, as the dried ink will have infused its binding agent into the fibers, and your technique will need to adjust accordingly. If you are working in a gloss-finishing medium, like metal point or graphite, the smooth deposit of material is effectively a new finish for the page, and it will change how the next layer is deposited, no matter how soft your pencil is. The main purpose of this step is to get maximum color at the surface. In dry media, because you are being so gentle, you likely won't produce a very dark surface. You'll need to go over it several times, possibly many, many times if the paper is very soft or thin, depositing pigment in many thin, even layers, until the surface is completely coated, blotting out the paper fully. In ink, you always lose some color to absorption. After the initial coat, the fibers are generally clogged with dried binding agent, so the second coat is usually almost perfectly the same color as the dry pigment alone, as most of the ink will dry on the surface, rather than as a stain in the paper. In both cases, with media which blend easily, (charcoal and copics) the second layer allows loose material to blend, obscuring your mark.


Why not some other angle, like 90°? You want a slight angle for one purpose only: crushing any subtle damage your initial marks made. Provided your second coat is just as gentle, the slight angle will maximally wipe out variance from the first coat. Think of it as polishing the finish, only much more gentle. At the commonly proposed 90° angle, your second coat would create the same kind of damage as your first coat, but will intersect with the initial damage in highly concentrated points, arranged in an even pattern, forming a checkered texture. Using a slight angle spreads out the intersections, and creates a broader, less even pattern, making it much harder to see.


6. Blend it if you can: This only applies to media which can be blended and worked after application. (So, pretty much just dry media, with the special inclusion of Copic markers) Using a tortillion, makeup brush, finger, or other blending tool, gently swirl the pigment in a soft, "fluffing" gesture. This moves any loose material around, allowing you to carefully even out its distribution. (With copics, you need a 0 ink pen, that's the one containing nothing but binder and medium. Just make quick, feathery full-length strokes back and forth across the area at a slight angle to your last coat. After quite a bit of work, the marks will begin to bleed together even more. Not all reactivating inks are available in an unpigmented form- in fact, Copic is the only brand I've seen that does it.)

Dry Media: The Other Method

One of my classmates called it cottonballing. I think she just made that up herself, but it's appropriate. That's what it feels like while you're doing it: soft and fluffy. Using a soft, dark, dry material, such as charcoal, begin coloring in your shape with a very light, gentle mark. Be careful to preserve the finish. Do not lift your tool. Color the whole shape in one long, slow, gentle, ponderously meandering mark. It is, in essence, the most delicate form that scribbling can take. Make no sharp angles or straight paths, always be curving, and do not stop moving. Keep your whole shape in sight, watching for an even distribution, and take whatever arbitrary path leads you through the uneven spots most frequently. Don't watch your tool tip, allow your subconscious take care of that while you focus on the work as a whole. To quote Bob Ross, "Think like water. Let it flow." Eventually, you will have applied a thick enough layer that the surface is completely coated, and cannot possibly get any darker. As long as you avoided patterns like the plague, and preserved the paper's surface, no discernible hand will be visible. Head to an edge and feather it off, following the contour.

Watercolor Pencils

If you plan to use this tool, use appropriate paper that can stand up to localized moisture.

These tools are kind of a gray-area hybrid between watercolor painting and traditional drawing. They are pencils containing dried, brick-form watercolor paint as a lead, plus some additional ingredients to make them less brittle and a little stronger so they draw smoothly. Unfortunately, there is considerable variation in WC pencil hardness, and manufacturers have not thought to advertise their relative pencil hardness. Some brands actually have different hardness from one pencil to another depending on the pigment! Find a set with a very soft black. (Actually, in general, find a set with the softest pencils you can find; they react to water activation better, as they apply as a loose dust rather than a dense accretion.) Use one of the methods from above for dry media to color normally, as though it were just a pencil. Now get out the water and use a damp brush to carefully soak the surface. You want to activate the medium and take up as little as possible. A shorter-bristled brush with a wide surface works best here, as they have less of a belly for pigment. Work the surface until all of the paint has been evenly activated and blended while wet. Let it dry.

If this sounds like it sucks: You could always do what my teachers suggested: take up printmaking. I wasn't satisfied with that answer. Other artists have their own techniques for hiding their hand. It's something of a technical mastery "magic trick" in the arts. These techniques are mostly found among hyper-realists and photo reproduction artists. If you know any of them, or meet one, and notice that they do a good job of obliterating their hand from the finished work, ask them how they do it in a polite way. Most artists are pretty down to chat about technique- especially if you buy a commission off of them.