It is not easy to frame your own watercolors. For one thing, unless you are an expert carpenter, you not only have the labor of cutting the molding, but you have to cut the glass and the mount as well. Instead, it is better to go to a competent frame maker. If he is a good one he will know just what moulding and mount to suggest, but if you are doubtful of his judgment, these are the points to remember:
1. The moulding must be neat and simple. Any fancy carving will detract from your picture. The moulding should be natural wood, or, if colored, neutral in tone. If the coloring becomes dirty, it should clean off easily if the moulding has been well treated. Fancy moulding is difficult to keep clean.
2. The mount should be off-white, or colored only if it does not clash with your watercolor. A bold gouache or tempera may be enhanced by a colored mount, but not a delicate watercolor. Unprimed, unbleached canvas makes a good neutral surround to a watercolor, but the frame maker must be skilled at fixing it on to the mount. A badly mounted canvas surround will ruin your picture. The mount should be generous in proportion. A thin mount looks mean and won't show off the picture to its best advantage.
It used to be fashionable to put lines round the mount, making a frame within a frame. But this I find fussy and distracting and entirely unnecessary.
Again, unless you are a good carpenter, it is better to go to a good frame maker for your frames. And, like water color frames, they should be simple. A highly decorated frame is often expensive and hard to keep clean. A simply designed frame will suit nearly all types of paintings, whereas only a few can stand up to masses of curls and squiggles. They are heavy to handle and difficult to hang. Unless you have the good fortune to live in a mansion, they will look out of place in a modern house.
Gold in small proportions enhances an oil painting but it must be gold leaf which is expensive. Other kinds of gold paint or leaf tend to tarnish and look shoddy after a while. So if you cannot afford pure gold leaf, it is better to leave the substitutes alone entirely and have them colored in a simple neutral tone to go with the scheme of your painting.
No painting, whether large or small, looks well in a mean frame. Have a generously proportioned frame. If you have painted on canvas, instead of a frame a strip of wood neatly tacked round flush with the surface will stop the painting from looking raw. However this method won't work with board. Board should go into a proper frame.