How is gold used in photography?

Answer 1

Many cameras, both film and digital contain at least some gold in their electronics. Gold is corrosion proof and highly conductive, making it fail safe for contact points. On the other hand, its high price will be reflected in the price of cameras using it.

Real metallic gold is used in solution as a black-and-white print toner. The process deposits real gold metal onto the silver image. Silver will tarnish over time but gold will not, so gold toning, especially if the image is printed on a well washed archival fiber paper, should result in an even longer lasting print. With resin coated papers we're not so sure about longevity since we don't know how long the resin coatings will last before they break down or separate from the substrate, but RC also responds well to gold toning.

Most gold toners are single solutions (no bleach-and-redevelop) which will yield a rich blue black image. They can also be used in combination with a sepia toner for a lush warm tone. Prints finished for gold toning should have a full normal range of tones and be normally developed, fixed and washed.