When it comes to choosing yarn color for weaving, it can come down to this central question: Is contrast important or not? In some weaves, color-and-weave for example, contrast is extremely important. In other applications, you may not want to highlight the differences between colors, but rather focus on highlighting one color or another. Contrast is created when two color values are different. For instance, a tinted yellow with a tonal purple
A quick way to determine if yarns have value contrast is to take a photo of the two yarns, using your smartphone. Use the edit feature on your camera to change the photo to grayscale. To do this on most smartphones, pull up the photo and select “edit.” Find the color setting and change the saturation to -100 by moving the slider all the way to the left. If you have the option, do the same for hue. You can also use one of the black and white filters, which will give you similar, but not always completely accurate, results.
If you can still see the two colors as distinct shades of gray, then you have decent value contrast. If you can’t see a distinction, then the yarns have low contrast.
Three yarns are shown above in color and with saturation removed. The image stripped of saturation shows how much value contrast each yarn has from the others. If you want to create a high value contrast, you might select the purple and yellow. If you wanted to create a medium value contrast you might choose the blue and pair it with either color. If you wanted low value contrast, none of these yarns would be appropriate as you would want to see very little distinction between them. Colors that have a similar hue can also have contrast from one another, for instance, a dark purple and light purple.
I have used this trick with yarn catalogs and even colors swatches from a screen. While not perfect, it still gets me decent information to help select colors that will stand apart from one another.
Value is just one aspect of color, but for weavers it can be a really important one if you need to make your yarn colors stand out from each other.
This information was adapted from A Weaver’s Guide to Yarn.