Hi this is Andrew on behalf of Expert Village.com and in this next clip I am going to be describing how to determine the color of thread to use based off of the material you are hemming; in this case pants.
The two options that you have to be considerate of when hemming and deciding a color of thread is first you want it to be an inconspicuous color to hide the fact that it's hemmed so it doesn't take away from the outfit. The other option would be considering if you wanted it to be conspicuous and to show it off. In the case of slacks for instance, it is more typically more for casual attire you would want to use a black thread so that you would not see it with the hem. Another inconspicuous thread color for this kind of pants, which is like a cotton casual attire pants that are brown and orange, they are using an exact color match so that is something else to consider.
With blue jeans there is typically a standard color and it is like sort of a rusty kind of orange-ish colored thread and it just typically goes with that material more. Another option you have if you wanted the thread to stand out, you would just choose colors that are pretty much the exact opposite on the color wheel or something that would stand out as the material for backdrop. In this case, you can see that blue and red really stand out on a white material and if you have a blue background, white and red the exact inverse would stand out. Typically the most important thing you can do is if you are trying to fix a hem is just look at the color of the thread that is already on the material and go from there. That is the easiest way to approach it unless you are starting new in which case just use your best judgment.