Hull paint

It varies.  Whose navy?

Tamiya makes a hull brown which is appropriate for the IJN

Titalic ship model

armor 2.0

Titalic ship model

Floquil is sadly gone but Testors, who owned them, has brought out many of the more popular colors in their Model Master acrylic line. They have bocxcar red flat #4881 and it's the same color as the old Floquil enamel. 

Titanic had, IIRC, more of a red lead paint scheme.  Which would probably want mixing Flat Red with Medium Gray--how much will be by eye.

Your references will be a better guide than some absolute formula.

And, there's "scale effect" to consider, as well.  So, your color needs to be a bit paler at 1/350 than at 1/144 or larger.

A person can be easily forgiven for just shooting a coat of Hull Red on--after all, no one is likely to pop up with digital photos of the launching to prove you wrong.

It's rather a bit like arguing over which black to paint the hull (me, I'd use NATO Black for scale effect, and to pe able to pick out details using "straight" black).

My 2¢; you local currency may differ.

CapnMac82

Titanic had, IIRC, more of a red lead paint scheme.  Which would probably want mixing Flat Red with Medium Gray--how much will be by eye.

Your references will be a better guide than some absolute formula.

And, there's "scale effect" to consider, as well.  So, your color needs to be a bit paler at 1/350 than at 1/144 or larger.

A person can be easily forgiven for just shooting a coat of Hull Red on--after all, no one is likely to pop up with digital photos of the launching to prove you wrong.

It's rather a bit like arguing over which black to paint the hull (me, I'd use NATO Black for scale effect, and to pe able to pick out details using "straight" black).

My 2¢; you local currency may differ.

 

I use Model Master British Crimson for most salties, red oxide (like Rustoleum red primer) for fresh water ships.

Since seeing the portion below waterline is not a realistic viewing situation, I don't worry about scale effect for full hull ships mounted above a base.