CORRECTION: these extra warp ends are really called accidentals, not incidentals. 9.2.09
I am a member of Complex Weaver's and, as such, belong to their Crackle Exchange group. We have two exchanges, one in the spring and one in the fall. Last week I received the samples from the spring exchange. I found one sample of particular interest. It was produced by Susan Wilson. Her sample consisted of differently sized blocks. The warp threads were silver, but the incidental threads were adobe.
Now, in case you've forgotten what the incidental threads in crackle are, go to Threading 4-Shaft Crackle and you will see that they are the "extra" thread inserted as you move from one block to another. My first thought was, aha, for the crackle project after this one, where I want to incorporate some black threads in the warp, I could use them for those incidental threads. Whether I ultimately will, I do not know, but in the notes I have begun for that project, I have included that idea. It's an idea I don't want to lose.
But then another light went off as I looked at her sample. If I want to make warp blocks different colors and have the colors aligned with the blocks, those incidentals mark the division! I had not been able to understand just exactly where in the threading, one block became the next block. Now I understand why I have hesitated to make the blocks themselves different colors, why I could not figure out exactly where a new block began. And I now finally realize that, should I use two or more color warp blocks, I will have to make a kind of arbitrary decision as to which block each incidental belongs. Yes, I can be very slow. Thank you Susan!
Here are some very simple 4-shaft drawdowns illustrating this. On the left is a one-color warp (orange) with black threads for the incidentals. On the right, is a two-color warp (blue and orange) with no separate color for the incidentals. I have made arbitrary decisions about the colors of the incidentals. However, if and when I do design a warp with different color warp blocks, I will have to work on systematizing the arbitrariness of the decisions!