A dye lot is the batch the yarn was dyed in. All of the yarn in one batch will be the exact same color and will have the same dye lot number on the label. Yarn from a different batch may vary in color. The colors of two different dye lots may look the same under certain lights and VERY different under other lights or in daylight.
Unfortunately, we are not able to match dye lots. Yarn is packed in cartons by dye lot and shipped to stores across the country – before long, that dye lot will be sold out. For this reason, we write a statement on every yarn label that you should purchase whatever you need of a dye lot at one time.
If you cannot find the dye lot you were using, the best thing to do is to take some of what you have to the store and try to get the best match. Look at it in natural and artificial light if possible. Work alternating rows with the two different dye lots to lessen the effect of knitting with a second dye lot.