PR48:2 vs PR57:1: Which Red Pigment for Your Ink System

PR48:2 vs PR57:1: Which Red Pigment for Your Ink System

Your offset ink for a high-speed web press just had a viscosity spike at 40°C because you substituted PR57:1 where PR48:2 was specified—wasting 2 hours of press time and 200 kg of substrate. That single mix-up costs approximately $1,200 in downtime alone, based on typical European gravure operations. These two reds are not interchangeable, and choosing wrong hits your bottom line directly.

Chemistry Difference: What Makes Them Distinct

PR48:2 (Pigment Red 48:2, CAS 7023-61-2, CI 15865:2) is a calcium salt of a monoazo dye. The calcium ion makes it much more resistant to solvents and heat than its sodium-based cousins. PR57:1 (Pigment Red 57:1, CAS 5281-04-9, CI 15850:1) is a calcium salt too, but of a different naphthol AS structure. The key difference? The molecular backbone. PR48:2 has a chlorinated aromatic ring that boosts its durability, while PR57:1 has a sulfonic acid group that enhances water solubility in the raw pigment state—but also makes it more prone to bleeding in polar solvents.

In practical terms: PR48:2 typically withstands 200 hours of solvent immersion (MEK at 23°C) with a color shift (dE) below 1.0. PR57:1 under identical conditions reaches dE > 4.0 after just 48 hours. That’s not a small difference—it’s the gap between a shelf-stable ink and a recall.

Performance Comparison Table

Data based on HONOR Pigment internal testing and published industry benchmarks. Your specific results may vary due to resin type and dispersion method.

Application-by-Application Guide

Gravure Printing (Solvent-Based Systems)

PR48:2 is the workhorse here. Its solvent fastness means you can run toluene, MEK, or ethyl acetate without pigment bleeding through subsequent layers. PR57:1 will bleed in any system with >10% polar solvent, producing a muddy undertone and staining downstream equipment. For gravure, always choose PR48:2 unless you need a very clean yellow shade—then consider PR53:1.

Offset Printing (Sheetfed or Web)

PR57:1 dominates offset because water-based dampening systems don’t attack it. PR57:1’s water bleed resistance is excellent (dE < 0.5 after 24h immersion), and its higher tinting strength (typically 10–15% more punch than PR48:2 per gram) saves costs. PR48:2 works in offset but costs more per kilogram—typically 15–20% premium—and offers no advantage unless heat resistance is needed (e.g., quick-set heatset offset at >180°C).

Water-Based Flexo

PR57:1 is the default choice for corrugated board, labels, and packaging. Its low solvent bleed ensures stable pH in the ink fountain. PR48:2 is usable but requires careful surfactant selection to avoid flocculation. If your water-based system runs at pH above 8.5, PR57:1 is safer. Below pH 7.0, PR48:2 may offer better transparency for overprint varnishes.

Solvent-Based Flexo or Screen

PR48:2 wins. Solvent flexo uses alcohols, esters, or glycol ethers—all of which swell PR57:1 particles, causing poor transfer and pinholing. PR48:2 retains its particle size distribution (PSD) within ±0.1 micron after 30 days in n-propanol. PR57:1 may grow by 0.5–0.8 microns in the same period, altering viscosity dramatically.

Pricing: What You Actually Pay

As of Q2 2025 market data (source: ICIS, industry estimates):

• PR57:1 (standard grade, bulk): approximately $12–16/kg
• PR48:2 (standard grade, bulk): approximately $18–24/kg

The premium for PR48:2 (about 40–50% higher) is justified by its heat and solvent resistance. But if you are mixing it into water-based inks for paper, you are overpaying by $6–10/kg for a property you don’t use. Conversely, using PR57:1 in a solvent system to save $6/kg risks a $1,200 production stoppage—do the math.

FAQ: 3 Questions Procurement Managers Ask

Still deciding? Read more about our full pigment portfolio or talk to a technical specialist. For a quick overview, our team can also send a one-page cheat sheet that matches each CI number to your press type.