10w40 synthetic, or whatever the manufacturer recommends.
Oops, wrong forum...
As for a pre-wash, the answer is "it depends". Sometimes it's necessary, sometimes not, sometimes helpful and other times not. It's not a recommendation of most of the film manufacturers. But it may or may not be a good idea depending on your particular combination of technique, equipment, film, film format, and developer.
In most cases it's not needed, especially for roll films in manual processing tanks.
For crud on the film, the most common source is airborne dust. Sometimes water is the culprit, and it can get there at at any point. Using distilled to mix and dilute your chemicals may help, and a short rinse in distilled at the end of your wash step also helps, especially if you have very hard water. If it's a chronic issue you may want to add filtration to your water supply, especially if you are using well water.
For air, make sure that the wet film isn't hanging in the airflow of AC or furnace vents. If you're processing in a bathroom running the shower on hot for a short time may help to increase the humidity and capture dust in the air.
For extreme cases you can buy/build/cobble up a drying cabinet. One easy and cheap solution is to get one of those hanging closet bags for long-term clothes storage. Hang the bag up wherever, put the film in (hanging from the bar inside) and zip it shut.
Scanners are another dust-spot source, usually it's on the optics rather than on the film, and unless it's very bad the easiest way to deal with it is spotting the image with the software of your choice.
Oops, wrong forum...
As for a pre-wash, the answer is "it depends". Sometimes it's necessary, sometimes not, sometimes helpful and other times not. It's not a recommendation of most of the film manufacturers. But it may or may not be a good idea depending on your particular combination of technique, equipment, film, film format, and developer.
In most cases it's not needed, especially for roll films in manual processing tanks.
For crud on the film, the most common source is airborne dust. Sometimes water is the culprit, and it can get there at at any point. Using distilled to mix and dilute your chemicals may help, and a short rinse in distilled at the end of your wash step also helps, especially if you have very hard water. If it's a chronic issue you may want to add filtration to your water supply, especially if you are using well water.
For air, make sure that the wet film isn't hanging in the airflow of AC or furnace vents. If you're processing in a bathroom running the shower on hot for a short time may help to increase the humidity and capture dust in the air.
For extreme cases you can buy/build/cobble up a drying cabinet. One easy and cheap solution is to get one of those hanging closet bags for long-term clothes storage. Hang the bag up wherever, put the film in (hanging from the bar inside) and zip it shut.
Scanners are another dust-spot source, usually it's on the optics rather than on the film, and unless it's very bad the easiest way to deal with it is spotting the image with the software of your choice.