I use the infused oils for color mainly, though comfrey has a lot of healing qualities as does calendula. I haven't been able to get a real scent to come through from the infused oils.
I use olive oil and just use it as part of my olive oil from my recipe. For the Yellow Dock Root I used it as 12% of my total oils. So say you your recipe uses 100 grams of olive oil, I would use 50grams of infused olive oil and the rest plain olive oil. It depends on what you are infusing and what color you want. I used the comfrey nettle infused OO as all my olive.
Here is a picture of the soap made with olive oil infused with yellow dock root.
You don't really have to measure (I don't really) Just use enough oil to cove whatever herb you are using. I have some arnica and calendula infusing I'll get some pictures of it for you later.
I use olive oil and just use it as part of my olive oil from my recipe. For the Yellow Dock Root I used it as 12% of my total oils. So say you your recipe uses 100 grams of olive oil, I would use 50grams of infused olive oil and the rest plain olive oil. It depends on what you are infusing and what color you want. I used the comfrey nettle infused OO as all my olive.
Here is a picture of the soap made with olive oil infused with yellow dock root.

You don't really have to measure (I don't really) Just use enough oil to cove whatever herb you are using. I have some arnica and calendula infusing I'll get some pictures of it for you later.
I have another question what is the diference between essential oils and scented oils? how would you used them in a recipe? how would you calculate them into the recipe?
This should help. http://candleandsoap.about.com/od/fragrancesandaromatherapy/a/fragranceoils.htm
As far as usage, that varies from oil to oil. Most fragrance oils you can use between 1/2-1 ounce per pound of oils in your recipe. So if you have a 4 pound recipe, you would use between 2-4 ounces of FO. Eo's are something that are even harder because some you have to be very careful with because some can be sensitizers. Look around on www.thesage.com for more info.
This should help. http://candleandsoap.about.com/od/fragrancesandaromatherapy/a/fragranceoils.htm
As far as usage, that varies from oil to oil. Most fragrance oils you can use between 1/2-1 ounce per pound of oils in your recipe. So if you have a 4 pound recipe, you would use between 2-4 ounces of FO. Eo's are something that are even harder because some you have to be very careful with because some can be sensitizers. Look around on www.thesage.com for more info.