Ask Madelyn: Testing for Colorfastness

Hi Madelyn! In your opinion, can you get satisfactory results by mixing mercerized and unmercerized cotton in a warp? I had an unmercerized orange bleed all over my project when I washed it, so I’m wondering whether mercerized would work better. The orange cotton was from a yard sale - is there a way to test yarn for color fastness? Thank you! Lynn

Hi Lynn!

First, I have used pearl (mercerized) cotton with unmercerized cotton without ill effects. Unmercerized cottons tend to shrink a bit more than mercerized, but I haven’t had that be a problem. If you were to use warp or weft stripes of one alternating with stripes of the other, depending on their width, you might get a very slight seersucker effect.

Any cotton can bleed, however, whether mercerized or unmercerized; you were unlucky with your orange. Usually, when I wash any cotton handwoven fabric with a mix of colors (especially strong colors mixed with natural), I wash the item by hand in barely warm water, rinse very well, roll in towels to press out as much water as possible, and then press with the iron on a cotton setting until dry. Most color bleeding happens as the piece dries, the dyes running into adjacent areas (rather than being spread by the actual wash/rinse water).

I haven’t had any issues with bleeding since doing this, but many weavers recommend using color-catching sheets during the washing process (available in the laundry section). That might be especially important if you were going to put the pieces in the washing machine (leaving them in water longer than if you are washing by hand). I would still remove the piece from the washing machine and press until dry (not allowing it to sit wet for any length of time).

To see if a yarn is colorfast, wind a pretty substantial butterfly and soak in warm/hot water with a white rag/old handkerchief. If the dyes are likely to bleed, the water will show some of the color. Even if it doesn’t, take the rag out and squeeze the yarn into it and let dry.

Madelyn

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If you have a weaving question we would love to hear from you! Please email Madelyn! Pictured above: Summer Lace Placemats and Mug Rugs by Suzie Liles Handwoven May/June 2017. View related & recent "Ask Madelyn" posts! View related & recent "Ask Madelyn" posts!

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