Can anyone advise me on how to mix my own sepia paint - ideally for oil washes. My local art store does not carry it. Many thanks in advance.

Hi bomber,
Basically, mix any brown with some black and you have sepia.I'd probably suggest using Van Dyke Brown as it's already good a dark brown shade.
The only manufacturer I found that makes sepia is Rembrandt. I bought mine online thru Cheap Joes Art supplies. They're an excellent source for Winson Newton Series 7 brushes as well.

Hey Mongo, you aren't looking hard enough. Holbein, Sennelier, Dan Smith, and Old Holland series also carry a Sepia color.

Also Sepia is not just brown and black. It's a mix of Mars Yellow, English Red Oxide and Mars Black.

This is from the old Historical Modelers Forum.

PH