The other day I was yarn shopping and picked up some colors for a project, and was trying to decide on the whether the values were different enough to work well with the stranded pattern I had in mind.
In the past I’ve taken a digital photo of my yarn and converted it to black and white, which is the quick and dirty way to check out the relative values. By discarding color information you’re left solely with the relative light/dark values. Since I had neither my DSLR nor a Photoshop enabled computer on hand I was sort of stuck…. Until it hit me that my cell phone camera had a black and white shooting mode!
I took a color photo of the yarns, then a black and white photo of the same yarns, and voila! Instant value grading! Hope that helps you in your next colorwork dilemma!