Foil Stamping
This is one of the areas where a logo that is great for the web or traditional print may not look as good as you had anticipated. And since it can cost more than print, you certainly want the quality to be evident. There are several things to take into consideration.
1. Simple designs transfer to this medium better than a complex one with gradients and fine lines.
2. Companies that do foil-stamping (traditional one color) require that the design be submitted as strictly black and white artwork. No shades of gray. Either a high quality hard-copy with no jagged lines or edges or a digital copy with the same requirements. (Just because it is digital, doesn't necessarily mean it is going to be better.)
3. Small letters and details tend to ' fill in ' with foil when heated so sometimes the text must be enlarged to make it readable.
4. For the cleanest result, a minimum of 2 pt. lines are preferred.
What Makes Good Artwork for Foil Stamping?
To the left is shown a typical layout of a logo or perhaps a city seal. If it was developed in color from the beginning, the possibility of it not being appropriate for other uses is more likely to occur. Although, at first glance this logo appears to be a good candidate for foil stamping, a few things need to be changed to produce a good imprint. On the plus side, all the lines are at least 1 pt.;(2 pt. is better) and the artwork is simple without gradients,shadows and is not rendered in a pen and ink style with a multitude of fine lines. This is the standard for logos and seals destined for print also.
Black and White Sample

In this sample you can see that just changing the color elements to black doesn't produce an acceptable version. The boat disappears and the strange item sticking up between the trees cannot be easily identified. Keep in mind that everything white will be black and everything black will be gold (or silver or whatever foil color you choose.)
Black and Gold Sample-1

The best way to check whether your artwork is going to look good as a foil stamp is to turn all the elements yellow or gold and put a black (or whatever color your book is going to be) box behind it. Even when it looks good in black and white, this little trick will show more accurately what it will look like. Here's one solution. The sail and flag have been given a white stroke to give it a little more definition and breathing room. The letters are large enough and not too close together so they should come out pretty clean. You could do it this way, but I think the next example is much better.
Black and Gold Sample-2

In this second version, the trees have been outlined (black on a black and white piece of artwork) and the sail and boat would contain the largest amount of foil and be the focal point. The sample shown is a fairly typical 2 and 3/4 inch size. If the logo is to go on the spine as well as the front of a book, that has to be considered also. Some logos are just too complicated to be translated to a very small size and end up looking like a 'blob' of gold.
Final Tip
Round seals almost always have the round text in all uppercase.
Some cities have fallen into the bad habit of trying to get their logos designed 'on the cheap' by having contests, designing by committee, or asking non-graphics trained personnel design their city seals.
Unfortunately, the quality of work has declined significantly
