one painting tip and one question

[Allan]

I've read that mixing yellow with black produces a nice faded black color

that's my tip

and now for the question

How would you produce the lower surface buff color found on British WW1 fighters?

I have some tan and white and will try them, but please tell me if you have another way

[Dizzyfugu]

Depending on the model, mixing other colors like a bit of red or blue also work wonders and bring black literally to life. Pure black, just like pure white, simply do not look good on a model.

The lower "paint" is AFAIK actually bare linen, covered with a clear lacquer varnish. Consequently, there's hardly a definitve tone for that - Revell 16 (Sand) has been popular, there's a Humbrol "Linen" tone (#74), which is very yellow-ish, too, but I think that any sand or beige tone will do.
Depending on the scale, I'd just add some sheen to the finish the bigger the scale becomes, and worrying about a textile structure makes also only sense at large scales.

[NARSES2]

The lower "paint" is AFAIK actually bare linen, covered with a clear lacquer varnish. Consequently, there's hardly a definitve tone for that - Revell 16 (Sand) has been popular, there's a Humbrol "Linen" tone (#74), which is very yellow-ish, too, but I think that any sand or beige tone will do.

Absolutely Dizzy. It's "colour" depended on the dope used, and the dope who applied it I suppose ?  , each manufacturer was free to use what they felt suitable despite official doctrine. It also darkened with age, although the service life of most WWI aircraft was very short and not many aged unless home based or held in reserve. So as Dizzy says any pale buff/beige colour is fine. I tend to add white to Humbrol's Linen (a very old tin) to tone it down a bit especially in 1/72.

[Allan]

then I'll whip up a mix of yellow and white and see how it goes
Allan

[NARSES2]

Add the faintest touch of brown as well Al.

[Allan]

will try it out Chris