One of the first things I learned in Home Ec Garment Sewing was that you always picked a sewing thread that was just slightly darker than the fabric you were sewing on. The reason is that when you get down to a single thread, the color of a single thread will seem much, much lighter than the spool of color altogether. This is also true for stitching. I'm sure Crescent Colours 12 Grain seen in a hank seemed dark enough for a sand color, but in actually using it to stitch 1 over 2 on 36 count fabric, it is much lighter than the hank of thread on the card. This is why I changed this thread for Weeks Dye Works Oak. I was at first worried that it was too dark. I am already using Crescent Colours Old Oak Tree for the palm tree trunks and the starfish in the picture below. But you can see when I pull out a single thread from the hank, it is actually not a dark tan at all.
I also used this technique for changing out Crescent Colours Frosted Sage for a darker grey to use to stitch a sea shell. In this case I substituted Weeks Dye Works Tin Roof. I did look at several Weeks and several Gentle Art threads, but this is the one I decided on.
You can see the result in the castle (Weeks Dye Works Oak) and the sea shell (Weeks Dye Works Tin Roof). I also like the fact that Tin Roof has a tiny bit of green in it, much as a natural shell would. I still have some stitching to do in each of these boxes, but I wanted to show the change in colors without the backstitching getting in the way. So the next time you do a floss toss and find that you really don't like the colors once they are stitched, don't beat yourself up. Just consider that the thinner the thread and the lower the fabric count, the lighter the thread will seem when you stitch it on the fabric, especially white fabrics.