Watercolour half pans vs tubes: which format suits how you work

The half pans vs tubes question comes up early for most painters, and it tends to attract more opinion than it deserves. The answer is not about what kind of painter you are. It is about what you are doing on a given day, at a given scale, in a given place.

Both formats use the same pigments. Both are available in artist grade from the major manufacturers. The decision is almost entirely practical.

What the format difference actually means in practice

A half pan holds approximately 2.5ml of dried paint. A whole pan holds around 5ml. A 15ml tube, by contrast, contains enough paint to fill eight to ten half pans. The economics are straightforward: tubes offer more paint per pound, particularly at the 14ml and 15ml sizes.

What the pan gives you in return is convenience of a different kind. The paint is already in the box. There is no squeezing, no palette to carry separately, no risk of a tube cap failing in your bag. You open the lid and paint.

The practical friction with pans is activation time. A dry pan needs water to soften before the brush loads properly. Drop a little water onto each pan at the start of a session and leave it for a minute or two, and the difference is significant. Skip that step and you will be scrubbing at hard surfaces, which does not help your brushes.

Tubes eliminate that friction entirely. The paint is moist and mixes with water immediately. At speed, and at scale, that matters.

When half pans are clearly the better choice

If you paint outdoors regularly, or carry your kit on public transport, or work in locations where spills and leaks are a real concern, pans are the obvious answer. A metal pan box closes securely, fits in a coat pocket, and does not care about cabin pressure changes on a flight.

Pans also suit painters who work small: sketchbook pages, A5 studies, detailed botanical work. At that scale, you rarely need more than a small loaded brush, and the pan provides it. The mixing area in a compact pan box is limited, but for small quantities it is enough.

There is also a maintenance argument. A pan palette, once set up, is ready without preparation. Many painters find that keeping a filled pan box by the desk means they actually paint more, because the barrier to starting is lower.

When tubes make more sense

The clearest case for tubes is scale. If you are working at A3 or larger, or laying in broad wet-in-wet washes, you need generous quantities of pre-mixed paint. A half pan, loaded repeatedly with a large brush, is slow. You may run out of mixed colour mid-wash, which is a problem that does not recover well.

Tubes also suit painters who mix colours extensively before applying them. If your practice involves mixing pools of colour on a large palette, then adjusting and working from those pools, a tube is faster and more controllable. You squeeze what you need, mix it, and have a usable volume immediately.

There is a cost consideration at the top end of the range. A 14ml Winsor and Newton Professional tube at around £11 to £13 works out considerably cheaper per millilitre than the equivalent half pans, particularly for colours you use in large quantities, such as a sky blue or a neutral wash.

Do the same paints behave differently between formats

For most colours and most brands, the pigment and binder are the same whether the paint comes in a pan or a tube. The pan is simply the dried version of the tube paint.

There are exceptions worth knowing about. Winsor and Newton manufactures its Professional pans with a slightly different formula that includes wetting agents, making them easier to reactivate than tube paint that has been squeezed into a pan and allowed to dry. If you fill empty pans from W&N tubes, the result may be harder to work than a pan bought as a pan.

Some pigments also behave differently after drying and reconstitution. Certain granulating pigments, for instance, may granulate slightly differently depending on how much water was involved in the original mixing. This is a minor consideration for most painters, but if you are working with specific effects that depend on granulation, it is worth testing your actual paint rather than assuming equivalence.

Climate and humidity also affect pans. In very dry conditions, pans harden faster and take longer to reactivate. In high humidity, pans may stay slightly tacky, which can attract dust. These are practical variables worth noting if you paint in extreme conditions.

Daniel Smith’s tube-only colours are worth a separate mention. A number of their most distinctive pigments, including several of the PrimaTek mineral colours, are not available in pan format. If those pigments are part of your palette, tubes are the only option. You can browse the full materials section for more on pigment selection.

How to fill a pan from a tube and why you might want to

Filling empty half pans from tubes is a genuinely useful approach for painters who want the portability of a pan setup but prefer to buy tubes for economy. The process is simple: squeeze paint into an empty pan, allow it to skin over for a few minutes, then cap it lightly and leave it to dry. Most paints take several days to dry fully in this format, and they will shrink slightly as they do.

The one caveat is that tube paint, once dried in a pan, may not reactivate as easily as factory-produced pans. With Winsor and Newton Professional, this is a noticeable difference. With Daniel Smith, the gap is smaller. For other brands, it depends on the specific formulation. Pre-wetting the filled pan before each session compensates for much of this.

For UK suppliers stocking empty pans and compatible metal boxes, Jackson’s Art Supplies carries a good range. Cass Art stocks both formats of the major brands.

The practical verdict

Buy pans if you paint outdoors, travel with your kit, or work at A5 and below. Buy tubes if you paint in a fixed studio space, work at A3 or above, or use paint in large quantities. Use both if your practice covers both contexts, which for many painters it does.

The mistake is treating the decision as a statement about how seriously you take the craft. It is not. It is a logistics question. Answer it practically and move on to the things that actually affect your painting.