To enhance the contrast of your engraved slate coasters, consider applying a tinted paint or a color-enhancing sealant specifically designed for stone surfaces. Choose a color that complements the slate while darkening the engraved areas for better visibility. Start by cleaning the coasters thoroughly to remove dust and debris. Then, use a fine brush to carefully apply the paint into the engravings, ensuring you don’t over-apply to the surrounding areas. Once the paint dries, wipe off any excess from the surface with a damp cloth.

To protect your coasters after enhancing them, apply a clear stone sealer. This will help guard against moisture and stains while preserving the newly enhanced contrast. Make sure to select a sealer that is safe for food contact if you’ll be using the coasters for beverages. Follow the manufacturer’s instructions for application; usually, it involves applying a thin coat and allowing it to dry completely before adding a second coat for optimal protection. Lastly, avoid exposing your coasters to excessive heat or direct sunlight, and clean them gently with a damp cloth to prolong their lifespan.