A Bit Redder

I got more red on the Midi this week, and I'm kind of confused by Martina's choice to use two reds on this. They both look to be essentially the same color to me. Both are in the red area I've completed. Can you tell the difference? One is from Thread Gatherer and the other is from Gloriana. I'm sure she has a reason. I feel like I'm going to finish this part soon, unlike how I felt for so long with part two. Since this picture, I've even put some pictures on the other arch too!