Watercolor Tubes Vs. Pans: Which is Better?

Watercolors in tubes, cakes, and pans have a lot in common, but there are some important differences, too. Each kind of watercolor has its own special advantages and limitations, and understanding these is key to selecting the right paint for your work.

Early watercolors were mixed by the artist in-studio or prepared in small batches by pigment dealers called “colourmen” until manufactured colors were introduced, first as solid cakes, then later in tubes. Ready-to-use watercolors in collapsible metal tubes were introduced by Winsor & Newton in 1846, and today they are available from many brands in a huge range of highly concentrated colors, including unusual pigments that are rare in other types of paint.

The most exciting advantage to using tube watercolor is the ability to instantly flood a page with huge volumes of liquid color. Since tube colors have a fluid consistency straight from the container, they mix with water instantly, and you can prepare a large amount quickly for the broadest applications. They offer an excellent variety of paint body and handling, from thin washes to thick, sticky highlights– something that’s not as easy with cakes and pans.

Tube watercolors generally travel well, but caps have to be kept clean and replaced securely. That’s never a problem with semi-moist cakes and pans. There’s no worry about paint drying out, because pans and cakes are made to be stored dry, and they can be reconstituted and dried repeatedly without diminishing paint quality. Travel kits designed to hold solid refills can make carrying a full palette of paint easy, convenient, and safe, and it’s easy to reconfigure your color assortment for the needs of the day by switching up the cakes or pans.

Image (right): “In the Generalife” by John Singer Sargent, watercolor, crayon, and graphite on paper, 1912

Early solid watercolors were not very soluble, so they had to be ground with water to prepare them for use. That changed in the second half of the 18th century, when William Reeves of London developed cakes that liquified readily with water without the need for grinding. Semi-moist watercolor cakes start out with a dough-like consistency and are pressed into their familiar tablet form. Pan colors, introduced in the early 19th century, are condensed and dehydrated from a thick fluid formulated for minimal shrinkage with no cracking.

Image (left): Antique set of William Reeves watercolor cakes, collection Joseph Allen Skinner Museum

Cakes and pans also include two special ingredients: plasticizers and humectants. Plasticizers keep the paint flexible and prevent it from cracking or crumbling. Humectants retain moisture in the paint and draw humidity from the air, so color wets quickly at the touch of a brush. Some manufacturers use natural honey as both plasticizer and humectant in one.

Semi-moist cakes and pans in their dry state have low water activity, and they retain their anti-microbial protection throughout the solid portion of the paint, even with repeated uses. That means leftover cakes are resistant to mold for a long time. If colors get stained from paint on the brush, a damp paper towel can remove the dirty portion and reveal the clean paint beneath.

Can you let tube watercolor dry and use it like semi-moist cakes? Absolutely. Artists have always used leftover watercolor, though results vary from brand to brand, and from color to color. Selecting tube colors based on how they perform when dry on the palette is a growing trend. Some dried colors may not re-wet as readily as cakes, taking longer to achieve saturation, while others come close to the consistency of pan colors. However, tube watercolors may lose some of their peak appearance and handling, and their antimicrobial protection, through repeated drying and re-wetting. Dried tube colors are not made to be as plastic and flexible as semi-moist cakes, so they can crack and split when they dry on the palette. Gum arabic and glycerine can be added to improve re-wetting and to reduce cracking.

Image (right): Etchr Lab Travel Mini Porcelain Palettes

Watercolors in one form or another are often memorable milestones in our development as artists. Watercolor cakes and pans are among the first paints we use in school, and a set of tube colors is often our first experience with professional-grade paint. For all the advantages of tube watercolors, however, don’t forget the professional-grade solid watercolors that rival the quality of any tubes. Not only are they beautiful paint, they also help you recapture the feeling of your very first time with a watercolor set!

Image (left): “Two Girls on a Lawn” by John Singer Sargent, watercolor on paper, 1889