I believe you are supposed to use olive oil, but im not 100%!
What are you substituting the oil with? What kind of recipe? You couldn't use butter for the oil in salad dressing. Sometimes it does matter what kind of shortening you use.
it usually is a mixture of oil and vinegar.
The most popular salad dressing to make with oil and vinegar is a simple vinaigrette. The ratio of oil to vinegar is around 3 to 1, although this can vary, particularly if a low fat dressing is required.
Oil and vinegar dressing is a heterogeneous mixture.
A dressing of that kind will not easily go bad. If the Olive oil and Vinegar separate, just shake it to reconstitute. Both Olive oil and Vinegar have an unrefrigerated shelf life of years. Although vinegar is in itself a natural preservative (all acids are), if you introduce high protein items like anchovies into the dressing, they will go off more quickly.
French dressing is made primarily from vinegar and oil. Ketchup is usually part of the mix, lending the dressing its signature red color.
Oil and vinegar dressing is a temporary emulsion. When the dressing sits for a while the oil and vinegar separate from each other. If you were to put this on the salad it would taste pretty disgusting because it would be entirely oil. So to avoid this, you shake the dressing and then add it to the salad so that the oil and vinegar is combined and it creates a good flavour.
Well, its not so much a matter of the thickness of the cooking oil for a salad dressing, but the taste it will impart to it. Extra virgin olive oil might have too strong a flavor, depending on what you are using as your herbs and spices and your vinegar. If you wanted a fairly bland oil, I would look to canola oil or peanut oil.
Vinaigrette
no
Oil and vinegar are the perfect combination to make a vinaigrette salad dressing and apple cider vinegar and Olive oil is part of a recipe for damaged dry hair.
Basic European dressing is 3 parts oil.