DMC 3683 to Madeira: Thread Conversion

Madeira 0606 is a close match that some stitchers report runs slightly lighter in value than the DMC original. On low-count fabrics like 11-count Aida, where individual stitches are clearly visible, a value shift can affect how the shading reads; on higher-count work where threads blend optically from a viewing distance, it usually disappears. Worth noting for careful gradient placement decisions.