Portuguese researchers have successfully recreated a mysterious blue ink used in medieval manuscripts, following a 15th-century recipe. This breakthrough, announced in September 2025, revives a long-lost natural pigment called folium, offering new ways to preserve ancient texts and understand historical art.

The Ancient Recipe Rediscovered

Scientists at NOVA University in Lisbon uncovered the secret behind folium, a purplish-blue dye from the Middle Ages. They followed instructions from a 15th-century Portuguese manual written by a text illuminator.

The team spent years testing the recipe, which involves extracting color from the Chrozophora tinctoria plant, native to the Mediterranean region. This plant produces tiny fruits that yield the vibrant blue shade when processed correctly.

Their work builds on earlier studies from 2020, but recent advances in chemical analysis allowed a more precise recreation in 2025. Researchers confirmed the pigment’s structure, which had puzzled experts for centuries.

This discovery ties into ongoing efforts to revive forgotten natural dyes, amid growing interest in sustainable materials today.

How to Make Medieval Blue Ink

The recipe starts with harvesting fruits from the Chrozophora tinctoria plant, also known as the giradol or turnsole. Workers crush the fruits and extract the juice, then mix it with other natural ingredients to stabilize the color.

Experts describe the process as simple yet precise, requiring specific timing and conditions to achieve the right hue. Unlike modern synthetic inks, this version relies entirely on plant-based elements.

Here are the key steps in the recreation process:

• Gather ripe fruits from the plant during late summer.
• Crush and soak the fruits in water to release the dye.
• Filter the mixture and add stabilizers like cloth or mild acids.
• Dry the extract to form a usable pigment for writing or painting.

Researchers tested the ink on paper, finding it matches samples from medieval books in color and durability.

Why This Pigment Vanished

Folium fell out of use by the 19th century as brighter, mineral-based blues like ultramarine became popular. These new colors were easier to produce and more stable, leading artists to abandon plant dyes.

Historians note that knowledge of natural inks faded during the Industrial Revolution, when factories prioritized synthetic options. Climate changes also made some source plants harder to find.

In recent years, events like the 2024 global push for eco-friendly materials have sparked renewed interest. This recreation aligns with trends in sustainable art supplies, seen in workshops and exhibitions worldwide.

The pigment’s unique properties set it apart. It changes shade slightly under different lights, adding a magical quality to illuminated manuscripts.

Impact on Art Conservation

Conservators now have a tool to identify and restore folium in old documents. This helps prevent fading and damage in priceless artifacts housed in museums.

The recreated ink allows for accurate repairs, ensuring colors stay true to the original. Experts predict this will aid in preserving texts from Europe, the Middle East, and beyond.

To show the differences, consider this comparison:

This table highlights why reviving folium matters for both history and modern use.

Teams are already applying the knowledge to projects, like restoring a 14th-century Bible in Portugal.

Broader Implications for Today

This breakthrough opens doors for artists and scientists alike. Modern creators can experiment with natural inks in paintings, textiles, and even food coloring.

It also inspires education programs, with schools teaching medieval techniques in art classes. In 2025, amid climate concerns, such revivals promote sustainable practices over synthetic alternatives.

Researchers plan further studies on other lost colors, potentially uncovering more recipes from ancient texts.

What do you think about bringing back these ancient techniques? Share your thoughts in the comments and spread the word to fellow history buffs.