Practically speaking, if you make your own watercolor paints, you will be making half pans or whole pans which will eventually have dried pigment in them that needs to be rehydrated before using. Perhaps, some people will think dry pans are inferior to tubes, but Homer (and Sargent) and quite a few other artists seem to have used pans by choice. So let’s take a look at the problems.
Unlike the oil painter, the watercolorist adds medium (water) to his brush before he loads it with pigment. This is why a different kind of brush had to be developed for watercolor that could hold water. In fact, since the watercolor brush didn’t resemble the hog bristle brush of the oil painter (which would hardly hold any water), it was originally called a “pencil” — yes, a “pencil”! Probably because these “brushes” were used to draw thin lines with as well as lay down broad washes and anything you used to make a “drawing” was called a “pencil”. Today in a museum you can still see drawing made with “point of brush.” But how much water do we add to our brush/pencil? This depends upon whether the pigment is in a tube or in a dry pan.
Tubes for pigment were invented by an American portrait painter working in England in 1841 by the name of John Goffe Rand. Winsor & Newton bought the idea and was one of the major companies to develop it. Rand apparently never profited from his invention. For oil painters it was liberating because pigment could be easily taken into the field. This probably led to the idea of a “pochade”, a color study done in the field. For watercolorists pans of dried paint were already being used, and I think the watercolor tube did not catch on as quickly because pan were a very serviceable alternative.
The pigment in a tube or a pan is formulated by the manufacturer to be at its best for that particular pigment. This is only right since you don’t want to buy watered down pigments at the price they are charging. In the case of a tube the pigment is of the consistency you would only want to paint a very tight, bright passage, but it wont “wash” very easily if at all. With pans, of course, the paint is completely or almost dry and can’t be used without wetting.
Let’s start with the problem of tube paints first because it’s the easiest. For a wash, the pigment out of the tube needs more water, but therein lies the problem. There is a problem because water also tints the value lighter (or allows more paper to show and therefore lightens the pigment’s apparent value) and reduces the intensity or strength of the hue (by separating the pigment granules further apart). (In other words white paint is not used). With additional water a dark blue pigment out of the tube like ultramarine blue gets lighter and “faded”. Good for depicting jeans. If that’s what you want, then it’s OK. But suppose you want to keep your color as dark and intense as it can be and yet be used in a wash. It can be done. Adding water does not necessarily kill the intensity and tint the value. How do you calibrate the amount of water you need in your brush to do this the right way. Here’s my idea for tube paints.
If you dip a brush into water, before dipping it in pigment, and take it out, there will be a drop of water hanging from the tip.
Sometimes it is not a full, round drop but you can generally see some extra water beyond the end of the brush. If you give that brush a shake, a quick jerk of the wrist, you will shake that drop off. The brush still holds water in its “belly” if it’s a good wash brush for example one made from Kolinski hair or Russian squirrel hair. (If it doesn’t, you should get a better brush.) If you give your brush two such shakes, it will remove some of the water from the belly. So we could have a metric involving the number of shakes you give your brush: none, one, or two. It is also possible to wipe the brush on a paper towel. This would be the ultimate drying maneuver and not recommended unless you want the pigment at tube consistency to put down a “dry brush” stroke – although some artists have learned to use a towel to just take off the initial drop. Shaking seems easier to me.
Another way to test the paint and water mixture is to see how runny it is on paper or palette. Since you can tilt either one different degrees, you can see when it begins to run rather than “bead” at the edge of the puddle of paint. Generally one works at a tilt of about 30 degrees, so this might be a good tilt to judge the dilution of pigment with water. Certainly when on paper, you don’t want your wash to run down the (dry) paper.
In general I find that one shake leave the right amount of water in the brush for an intense colored wash. This works well for me with tube paint that is still at the manufacturer’s consistency. But then there is the question of the dried pigment in a cake or just pigment, formerly from a tube, that has dried in one of your palette’s wells. This seems to be how Homer began each painting (with dry cakes of pigment.) Here you have to reconstitute the pigment to the consistency you want.
What you are actually trying to do is re-hydrate the gum arabic in the cake. One of the unusual characteristics of dry gum arabic is that it can dissolve in the same volume of water . If we knew how much gum arabic there was in a cake of pigment, we could used the same amount of water to dissolve it. We would have to grind up the whole cake however. The fact that there is a lot of dry pigment sitting on top of each other would make it hard for water to penetrate to the bottom. What we actually want is to re-hydrate only some of the top gum arabic (with pigment and other additives), at the least the amount we want to hold in the brush. Many people spray the dry pans from a spray bottle before they start working and then delay a bit, for example have breakfast, and then come back to work. Another answer might be to add a brush-full of water to a cake without shaking it. We don’t want to add too much or we run into the same problems too much water causes with tube paints. However, if too much water is on the top of a cake, it will slowly dissolve more and more of the cake as it seeps in — probably too slowly for the painting we are doing however.
Bruce McEvoy (see his handprint website here) wrote in a comment to this post that he has “learned to judge the dilution of the paint I want just by looking at it as it dissolves, but it’s a knack I’ve only developed with experience.”, so that’s the ultimate aim. I keep a old piece of watercolor paper beside my current work on which to try out dilutions if I have a doubt. My personal problem is that I am likely not to add enough water, so I test my dilution on the extra paper.
One caveat: because you are likely to scrub the cake with your brush after adding water to hurry up the process, there is the possibility with some pigments of also “sandpapering” off the tips of your brushes hairs. Bruce McEvoy in his comment to this post suggests holding the brush horizontally to the pan and twirling the belly of the brush over the pigment to avoid point damage to the brush.
I think there is a practical difference between tube and cake paints that can’t be denied. To lay down a really big wash on a really big piece of paper tube paints are infinitely easier. In fact, pan paints suggest working on relatively small size paper and not having big washes which is, in fact, how Homer worked. I don’t think I have ever seen the classical uniform wash over a big area in any of Homer’s watercolors. In fact, that’s one of the things I like about his work. It is complex with multiple small washes.
