Sacred Stone Logomark
Every logo I create is always initially done in one colour and there's two main reasons why:
1. Colour can strongly influence our emotional response. When you strip it away, the logo should still reflect the style and mood of your brand. Colour should never be a crutch in design.
2. There once was this commonly used thing called a fax machine and it made everything look ugly. If your logo was anything other than high-contrast black and white, it came out a barely recognizable blob of fax toner. While the fax machine for the most part is now defunct, there are still many opportunities when the only option is black and white. This could be an ad in a newspaper, your logo printed on receipts, and often promotional merchandise can be expensive if you're running more than one colour. If you don't have solid one-colour version of your logo, you will get the same ugly fax toner blob result because a logo needs to have high contrast in these situations.
While it may seem like a small detail, it's the details that make all the difference in a visual identity being effective across all media.