Default to chumra (stringency) if it’s ambiguous, but ask a rabbi. Many shades of brown are considered tahor unless they clearly tend toward red.
Here’s a draft for a blog post that explains the clearly and sensitively. Title: Understanding the Niddah Color Chart: A Guide to Halachic Color Discernment
The Niddah color chart is not about finding loopholes. It’s a halachic tool rooted in kindness, removing doubt so a couple can live peacefully ( shalom bayit ) within the framework of Torah law. When in doubt, reach out to a rabbi who is both knowledgeable and sensitive — no question is too small when it comes to preserving the sanctity of this mitzvah. Disclaimer: This post is for educational purposes. Always consult your rabbi for practical halachic decisions.