Trying to compare vials to the color chart is a pain in the butt. I'm using the same kit, cycling, and have recently seen the colors you have. Saltyfilmfolks has given you a good reading IMO. But since there is more tests in your future here's my .02.
I found it helps to notice the full spectrum of each chart, and make a relative comparison. Since these hobby kits aren't lab-grade to start with, and for our purposes we are usually going for the 0 ppm reading, try to get a yellow hue vs an orange for nitrates, a blue vs a purple for nitrites. Ammonia is harder because that .50 ppm color seems like a non-linear step in the spectrum. Basically, we know we don't want Dark greens (NH3/NH4), Dark Purples (NO2), and (Reds, NO3). Get your vials as close to yellow-vomit-color, blue and yellow as possible and you should be in business. We'll never get exact matches to the color but we can gauge where we are in the spectrum.
