I know that a large proportion of the watercoloring community purchases their paints in tube form, as it seems to be a bit more economical than a whole set of pan paints or the single pans, themselves (there are always exceptions, though). I am also sure that most of us have had to deal with a tube that has hardened on us.
This can be a nightmare, and no one wants to throw out the remainder of the tube, because often we have spent some good money on the paints and chucking it out would be a real waste. Recently, I even purchased a discounted tube of Cadmium Orange from a supplier, and the contents were tough as a brick. So sometimes I get some old stock too, and I want to use what I paid for. Here are some options for making use of the paint in the hardened tubes that I have come across.
I know I used this option with the aforementioned tube of Cadmium Orange, and it worked to an extent. I got a tubular stick of the paint out, which I could reconstitute in my palette with some water. So just shoving it out of the tube is an option, though maybe not the best. There are times where this option is not possible, because the tube has hardened so much. Also, excessive force may split open the tube, itself.
Cut Open the Tube
I know of several individuals that have taken this approach to the problem. It works mainly because watercolors, unlike acrylic or oil paints, really have an almost infinite lifetime. It is as simple as adding water to bring it back to life. It is true that once dried it will be more difficult to achieve the depth of the hue as compared to the original soft paint, but it is still a good result and prevents waste of the color. It simply involves breaking up the contents and putting them in a palette well or some other receptacle before adding water.
Add Watercolor Medium or Water to the Tube
This is another option, but it may take some more effort than the others. You have to begin with a tube of watercolors with a neck empty of hardened paint, because you want the medium or water to enter the main portion of the tube’s contents. Then twist on the cap and massage the contents together, slowly. It may take some time, perhaps with breaks in between. However, the moisture in the tube should slowly soften the contents to a viscosity that will be able to be pressed from the tube.
Add Glycerin to the Tube
This one I just read about in Herb Olsen’s Guide to Watercolor Landscape, and it is similar to the above option. He mentions that to get the tube pliable again, add several drops of glycerin into the tube with an eyedropper. I assume that there needs to be an access cavity into the body of the tube, so there should be no hardened contents clotting up the hole. However, once added, just twist on the cap and massage contents together, or knead them, if you prefer to reserve massaging for spas. 🙂
If you are hesitant to use glycerin, rest assured that it is just a viscous, water-soluble liquid that will not have a significant difference on the properties of the reconstituted paint. The paint should be applied as normal, and its behavior will be nearly identical to that of the original soft contents.
I am sure that there are other methods out there that work as well, these are just a few that I came across that seem to work well. The purpose of most of these methods is just to reconstitute the dried paint with its pigment, binders and fillers. Some paints are resistant to the drying effects of aging – I believe M. Graham paints are one of these, as they use honey in their formula and claim that it prevents such desiccation and hardening. There are bound to be others.
Please share your own stories and experiences with a hardened tube of watercolor, as I am always eager to hear how other people go about solving a problem. It will help me and anyone else who stumbles upon this post, and maybe save them a few sighs and groans when they find that prized tube of Rose Madder in the bottom of a drawer, only to find that it has developed a bit of agoraphobia and prefers not to come outside. 🙂