Most brands of watercolour paint come in a choice of two formats: dried pans or moist tubes. Watercolour painters often ask how to choose which to use – what are the benefits of using watercolour in pans versus in tubes. To help you decide which will work better with how you paint, here are the advantages and disadvantages you can expect from each format.
Sizes – Pans
Watercolour pans come in two rectangular sizes: a full pan and a half pan. (A full pan is sometimes called a whole pan.) Across brands the sizes of pans are nearly the same standard size but not quite, so that’s why many watercolour boxes have bendable compartments that allow for slight adjustments to hold the pans. Travel watercolour boxes that do not have adjustable compartments will not work with all brands of pans because even a part of a millimetre difference means that they won’t fit in the slot. In the Holbein half pan sets the plastic pans come with a magnet on the bottom of each pan to hold it in place in the box.
A few brands do other sizes than the two common ones: Blockx do a Giant Pan (a generous 3.5 by 2.5 inches), Gansai Tambi are much larger than standard and Coliro do two sizes of round pans. Daler-Rowney does a delightful miniature set of 1/4 pans. To refill it you purchase extruded half pans and gently cut them in half with a craft knife.
Pans also vary in their formula and method of manufacture. Some pans are extruded like dough, cut into cubes, let dry, and then placed into pans as a hard cake. These can often be seen sticking up above the rim of the pan. Those that are poured also vary. Some are poured once and allowed to shrink so the pan is only partially full, while other brands top up the pour a second or third time for a fuller pan. And of course the actual formula of the paint differs, with some paints adding some honey, some having different amounts of gum arabic binder, some adding wetting/flow agents and some not. Some with honey are not as soft because they are extruded, while the poured honey paints can be only semi-hard. These differences in formula are more readily visible in a pan than a tube, as a shiny/matt, sticky/smooth, or soft/hard surface.
Sizes – Tubes
Most brands of watercolour make two sizes of tubes, their small and their large. The most common sizes are 5 ml, 10 ml, 14 ml, 15 ml, or 21 ml. In addition to their two regular sizes, Winsor & Newton also do a very large 37 ml tube. Some of the brands that only do one size of tube often do it in an unusual size such as 7 ml, 9 ml, 11 ml and 24 ml.
Occasionally you may find a favourite paint and not have a choice of format. There are some brands that are only available in one format – some that only come in tubes and some that only come in pans.
Comparing the Benefits of Watercolour Paint in Pans Versus Tubes
*Note: One of the main reasons people buy tubes is as bulk refills for their pans. If you do this and let the paint dry, then you have changed your moist tubes into hard pans and the characteristics on this list that apply to pans will also apply to your home-filled pans as they are no longer moist tube paints.
Convenience – Portability and Speed of Set-up
Pans are more convenient and so are the usual choice for portable paint boxes. Opening and squeezing out all the tubes each time you paint is not as convenient. You can also get more colours in a smaller space with half pans than with tubes, which means a lighter, smaller box. Some tube colours do not completely dry on the palette so if you are travelling and you have used tubes, your palette can remain sticky or even wet so all the colours may mix or spill, especially in hot weather.
When travelling tubes can be a problem on an aeroplane. The unpressurised hold can cause the paints to expand in the tube and they may spurt out excessively when opened later.
Convenience – Faster Wetting
Tubes are moist paint so they are already soft. Because pans are dried hard, they usually take longer for the paint to soften with water. You can alleviate this somewhat by spraying water over your palette five minutes before you begin painting to let them soak up some water to soften them up. You can also use an eye dropper or small plastic bottle that lets you squeeze a few drops on to pre-wet them. Also, some brands of pans are softer than others. Be aware that although some painters love the more moist pans, some find the semi-hard nature a problem both because they can be ‘sticky’ and it can mean that if the box is left on its side, then the paint very slowly responds to gravity and can sag into the next colour.
Customise Your Palettes or Your Pans
If you want something other than half or full pans you can squeeze paint into a wide variety of ceramic palettes, or special travel boxes. If you want a special mix you can fill an empty pan from two tubes and stir it with a toothpick or pin. If you like your pans only half filled so that there is room for water and a brush without overflowing, you can fill them only half way.
To fill a pan from a tube: squeeze paint around the inside bottom edge of the pan and then into the centre, tap the pan on the table to settle the first layer, repeat for a second layer, then stir in a circle around the pan with a pin for a minute to get rid of gaps and bubbles and evenly distribute the paint. Let the pan dry for one to two days. It will shrink by up to 50%, which is how some poured pans come anyway. Extruded pans can come partially or very full.
Large Paintings, Large Areas of Paint, and Large Brushes
Anything A3 or larger can be considered a large watercolour painting. With tubes you can mix up a large amount of colour on a palette quickly, dip into it with a large brush and paint large areas quickly. If you squeeze more paint into your palette wells than you ended up using, you haven’t necessarily wasted it, you can rewet it in the future, just like a pan. Half pans are so tiny that it is hard to get paint out with anything but a smaller brush.
After you take the wrapper off of a pan of watercolour you may not be able to tell what it is anymore. Some brands have a number printed on the bottom or the brand logo, but most do not. Most dried colours are very dark because they are concentrated, transparent colour and even bright yellow can look like dark brown. So it is a good idea to arrange your pans in your box in an orderly way and not move them, so you know where the colours are – because the cool reds, violets, cool greens, transparent browns, and blues can all look like black in a pan. Unless you make a colour chart to refer to with brand and colour number, and use a Sharpie marker pen to write the number on the bottom of the pan, you may not even be able to replace the exact colour because you don’t know what brand or colour it was.
On the other hand, you always know what is in a tube, because the name remains on it.
Wear and Tear on Brushes
Using pans generally causes slightly more wear of watercolour brushes because you have to scrub a bit in the pan to pick the colour up. A well-known watercolourist prefers pans and says she accepts that she will go through a lot more brushes. If you like pans and know that you go through a lot of brushes you may wish to choose more economical brushes. Again, though, you can minimise this by wetting your colours and letting them soften before you start with your brush. I have found that some brands of tube colour dried on a palette can be quite hard to re-activate and in that situation, the dried tube colour will be the one that is harder on your brush.
Tubes are more economical than pans, and you can also think of a tube as a bulk refill for a pan. You can buy the extra large 24 ml or 37 ml tubes for even bigger savings. Because the tube paint contains water that will evaporate from the wet paint it will shrink in the pan and you will have to top it up a second time if you want to completely fill the pan. But I like a half filled pan, it gives room for water and the brush to swirl. But not everyone wants to squeeze tubes into pans as you are losing the main benefit of the tube, that it is already wet and ready to go. So some painters don’t think of a tube as a pan refill, but as a moist form of watercolour and they use it from the tube on a palette.
But even though they cost less per volume of paint, somehow tubes don’t seem to last as long. Many painters have told me that their pan paints have lasted for years but they go through a tube really quickly. I have also experienced this and it can be quite surprising. It is easy to use a lot of paint from a tube but a bit harder to use a lot from a pan. And pans are more concentrated because some of the volume in a tube is water.
My rough estimation is that a 15 ml tube of Horadam will make about eight to 10 half pans if you are using the tube as a refill. But the pans are not quite as full as those filled by Horadam because they top up their pans after the first shrinkage. See the ‘Customise’ paragraph above for a good way to fill your pans.
There is also a bit more wastage in several ways with tube paint than pan paint (see below). And in an effort to avoid wastage sometimes you can be stingy with the amount of paint you squeeze onto the palette, which may hold back your painting as you scrimp.
Another thing to consider when squeezing tube paint into a pan is that the formula for the paint in the pan and and the paint in the tube is different for some brands – for example Winsor & Newton extrude the paint like clay for the pans and place it into the pan as a dried cube. (I was lucky enough to visit their factory in London before they moved their production, and got to see the process – it was fascinating.) They say that these two different formulas mean that their pans are easier to re-wet than the paint from their tubes after it has dried on the palette, because they’ve added wetting agents to help get the dried paint in the pan to activate. For other brands the paint is the same for both – for example Schmincke fill their pans with the same paint as their tubes and it takes three cycles of filling and drying for a pan to become full. So, for some brands the dried tube paint is not supposed to revive as well as the ready-made pan paint does, though some people have done tests and found that any difference is not really noticeable.
Old Holland say that their paint in tubes and pans is the same, even though they extrude the paint for their pans, just that the pan paint has been left to dry and so the artist must re-hydrate the paint.
*Note: Fixed cost per unit
Small tubes (5 ml – 11 ml) are much more expensive per volume than large tubes (14 ml – 24 ml) and half pans are much more expensive per volume than full pans. In some paints the price for the small tube is almost the same as the large tube. This was explained to me as being caused by a fixed per unit cost- each item has to be handled multiple times (mixed, filled, labelled, packaged, inventoried, stored, shipped, marketed, etc.) and all those costs are the same per item whether it’s 5 ml or 15 ml.
There will probably be some wastage in the lid and the threads of a tube, though you can wet it and scrub your brush over it to use it up a bit. Another small wastage is that it can be hard to get all of the paint out of a tube without cutting the tube open, whereas you can reach all of the paint in a pan.
You may squeeze out more paint onto your palette than you will use, either intentionally or because tubes are often filled very full and when you unscrew the cap for the first time the paint acts like it is under pressure and a little or a lot can shoot out. You can help prevent this by holding your tube upright and tapping the folded end lightly against the table top to encourage the paint to go to the bottom and any air bubbles to go to the top. If you take off the lid and more paint squeezes out than you want, you can encourage it back inside by slightly squeezing the sizes while holding it upright and it will usually retreat enough to get the lid back on. If you can’t get it back inside, remember that the dried paint on your palette isn’t necessarily wasted if you can rewet it in the future. You can also just squeeze that excess into an empty pan to use later.
Tubes Can Dry Up
It is not uncommon for tubes of watercolour to dry out, especially if they are more than a few years old or it is a little tube. Some painters find this a huge drawback to using tubes.
If a tube of paint dries up and you can’t get any out, you can quite easily slice open the side of the soft metal tube and peel it open. Then just use it like it were a dried pan. But you can’t make the paint moist in the tube again.
Sometimes when you open a new tube you can squeeze out far more than you needed just trying to get to the pigment because at first all that comes out is the gum arabic binder. This separation of pigment and binder can’t happen with a dried pan. Fortunately, if you are using the tube as a refill for a pan you can just continue squeezing it into the pan and stir with a pin as described above. If you are using it as moist paint then you can stop squeezing and try stirring inside the tube with a pin to mix the binder back in.
I know that in the factory they rotate tubes of oil paint every few weeks to try to keep the binder from separating from the pigment during storage so you may wish to try that in your studio with watercolours, if you have a big problem with that. Some colours seem to be more prone to separation than others. Cerulean, for example, will often separate, perhaps because the pigment is often ground quite coarsely, you can see it is grittier, so it must be harder to suspend in the binder.
Colour Strength and Brightness
Some painters believe that tube colours have more pigment. Others say that pans are more concentrated. As mentioned previously, for many brands it’s the exact same paint, the tube just already has water added and with pans you have to add the water. So after you have added some water to the pan paint to rehydrate it they should be quite similar. I think the feeling that the colour is stronger with a tube is simply that it mixes so easily without much water that you are actually picking up more paint on the brush. So if you want your pan colour to be as strong as your tube colour, you need to dampen it in advance, and scrub up a good amount of paint into a wet mixture that isn’t mostly water, so you also get a good amount of paint on the brush. Then you will find that both formats are very similar in strength.
If you want strong, vibrant colour and large pools of colour for even washes then you may prefer the moist tube paint and I have heard many artists say that their painting improved considerably when they switched from using dried pans to moist tubes.
On the other hand, many fans of pans don’t want strong colour, they don’t want to get too much paint on the brush, because they like to layer more transparent, diluted paint, not apply a brushful of saturated colour. So they don’t activate the paint as much and they use more water on their brush so the colour is more diluted. These painters feel that a pan is more easily controlled, especially if you measure the water that you add by drops, so you are consistent with your dilution.
Cleaning Contaminated Colours
Dampen the surface of a pan and you can wipe just the top layer off and the paint underneath will be clean again. Tube paint on a palette can be quite muddy by the time you are finished painting and it can be hard to salvage the little bits left on the palette. Although if you have larger lumps, you may be able to spray water on them and pour off any mud.
With a tube you get to choose how you want to use it, it is more versatile.
Do You Have a Preference of Format?
Well, those are all the positive and negative attributes I could think of. If you can add other reasons that you prefer a pan or a tube, please let me know in the comments below.
To add to your choices there are a few more formats, though they are not available in as many brands. In addition to tubes and pans, watercolour comes in liquid, stick, and pencil form. Liquid watercolours can be a creamy fluid or very fluid like ink, but are all concentrated colour and are made with a gum arabic binder so can be re-wetted and lifted from your paper. The sticks are similar in consistency to pans, they are extruded paint left to dry. You can draw with them on wet paper or you can wet parts of your drawing afterwards. Viarco make a stick shaped like a tailors chalk. Use the pencils to draw with and then run a wet brush over to make parts of the drawing flow.
A few readers have suggested that watercolour sticks make great refills for pans. I have not done this but it sounds like a good idea. You would just need to break the stick into smaller peices.
In the end, many watercolour painters use a combination of tubes and pans, perhaps with a few sticks or pencils for fine lines. Those who prefer pans might have French Ultramarine or Cerulean Blue in a large tube for quick, large sky washes. But there are some painters who are loyal to painting with just one format. Knowing the benefits of each will help you decide which you want to use.
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