Rose_P

These cards can be helpful for the general idea, but be aware that the dye lots change, sometimes quite radically. I found a forest green Kona in one local store, but not enough for my project. I went to another store in the same chain and found the same fabric, but luckily I brought a swatch because it was different enough that it wouldn't work in the same quilt with the other. I went 20 miles out of my way to a third store, and found a third shade of the same one. Nobody had enough on a bolt so I had to order online to get the quantity I needed all matching. This is not intended as a slam of Kona. Anything that is dyed in lots may have variations.

Online, as you have indicated, it is the differences in monitors that make the fabrics look different as well as the difference in lighting where the pictures were taken. If you have ever checked out the paint displays at Home Depot or Lowes (probably many others), they have a box that has three different lighting types showing the same paint, which looks dramatically different under each light. There are too many variables to know for sure about fabric, and in fact what matches in a brick and mortar store under their fluorescent lights might not match in your light at home.

If you look up into the corner of a painted room you will see that the color on the left will not be the same as the color on the right, even though you know they match exactly. It's because each wall catches more or less light depending on where the windows are or what lamps are on. This is what you're up against not only with a picture but in person. Just as you have never lost sleep over the walls looking unmatched in the corners, you probably will not have too much trouble finding acceptable matches for your fabric, wherever you buy it.