You can also find a photo of the prototype in the Measure or scheme intended, approximately the same size as the model.
For 1/700, this is often easy as many photos reproduced in books are more or less kinda 1/700.
For larger scales (e.g. 1/350), find a photo of part of the ship.
B&W photos are often quite indicative of the intensity of the colours based on the available light (when the photo was taken and quality of the developing and printing).
While it will not show the actual "colour-scale-effect," photos will often show how bright or dark a known prototype hue is "at a known scale distance."
Personal preference is to cut all prototype colours with the same "reducer," USN Light Gull Grey.
As said so well above, this subject is a metaphorical minefield or walk, barefoot in a cow pasture.
Best of fortune.
These rules are useful (if not complicated), but are only applicable assuming the color used is correct to begin with. Paint a piece of scrap plastic with the desired paint, and when dry, hold it next to the model and judge if the color looks "right" or needs fading for that particular scale. Same thing for military vehicles, tanks, etc.
Yes, many of us on this forum apply scale effect on our 1:700 models.
As far as I'm concerned I stick to a rule I found on SteelNavy years ago (don't know its origin): I add a percentage of white equal to the square root of the scale denominator.
for 1:700 : square root of 700 is around 26, so I add circa 25% of white.
Two exceptions :
- Light and transparent colors (white, yellow, buff, red, green): I add 5-10% of neutral gray (Tamiya XF-19). This gives a very realistic effect on whit IMHO, taking away the "toy effect".
- Navy Blue (5-N) : I add 30-40% of white as this shade is particularly efficient in masking details.
I do apply the same rule on my aircraft.
I know others have different rules but do use a scale effect too.
Some modelers prefere to apply a light heavily diluted gray coat on the whole model when finished.