I recently used a liquid lake yellow color in my soap. After it was sitting in the sun a few hours, I noticed the color faded considerably. Does anyone use liquid lakes and if so, what has been your experience with them?
Technically, there's no such thing as a liquid lake. Lakes are dyes that have been converted to insoluble pigments. They could be sold as a powder or dispersed in a liquid, but it doesn't make a difference.
Dyes and lakes tend to be photosensitive. They will pretty much all fade in the sun, but some MUCH more than others. I don't think you can generalize about it past that, so if it's a concern you have to test the specific colorant.
Some people are using lakes without knowing it, because they are one of the many types of colorants that can be used to color mica.