Comparing monoazo yellow PY3 with diarylide yellow PY12 — chemistry, shade, applications, and selection guide.
PY3 and PY12 are both azo yellows but with distinct chemistry — PY3 is a monoazo (single -N=N- group), PY12 is diarylide (two coupled azo groups). The chemistry difference produces noticeable differences in shade, strength, and price.
Choose PY3 for cleaner, more greenish shades in inks, architectural paints (interior), textile printing, and rubber compounding where Blue Wool 5-6 lightfastness is sufficient. Cost-effective for high-volume applications.
Choose PY12 only when you need the higher tinctorial strength of diarylide for cost-effective high-color-depth inks (especially in low-cost packaging printing). Always verify the specific PY12 grade is certified free from the 24 banned amines — many traditional benzidine-derived PY12 grades are NOT REACH compliant.
Traditional PY12 was made from 3,3'-dichlorobenzidine which can release banned aromatic amines on cleavage. Modern certified PY12 grades use replacement chemistry that doesn't generate banned amines. Always request the 24-amines-free certificate per shipment from your supplier.
Yes — PY3 is inherently REACH compliant when sourced from a certified manufacturer. The shade is cleaner (more greenish) than PY12, so you may need to recalibrate color formulations. PY3 is commonly used as the safer alternative for textile and packaging applications.
Share your binder system, processing temperature, and required performance — we'll recommend the right grade and ship a free 50-100g sample for qualification.