The Secret To Colouring Eco Resin

How to Colour Eco Resin, Jesmonite & Plaster with Pigments

Colour turns simple casts into eye-catching pieces. Whether you’re working with eco resin pigments, Jesmonite pigment, or traditional plaster pigment, the right colourants and ratios will help you achieve consistent, vibrant results. This guide covers eco resin (ARC), acrylic resin pigments, colouring Jesmonite, and pigments for plaster and gypsum-based mixes, plus pro tips for smooth, repeatable finishes. For more casting inspiration, visit our resin casting guide.

Colouring Eco Resin with Pigments

Eco resin, such as ARC water-based acrylic resin, is a low-VOC casting system that’s safe for indoor use and easy to clean up. Because ARC is mineral-based and naturally opaque, adding colour with an eco resin pigment or eco resin powder is the fastest way to introduce depth and personality.

• Go light first: Start with a small dose and build up. Highly concentrated pigments go a long way.

• Measure by weight: For consistent colour from batch to batch, weigh both mix and pigment.

• Target load: Keep total pigment at ≤ 2% of the mixed weight to protect cure strength and surface integrity.

• Blend well: Pre-disperse pigment before adding to your main batch to avoid streaks.

Tip: ARC Pigments are designed for water-based acrylic casting systems and are a reliable match for eco casting workflows.

Acrylic Resin Pigments & How They Work

With acrylic resin, your colour needs to disperse evenly before the mix begins to set. Use acrylic resin pigments (liquid dispersions) for fast, uniform colour, or try acrylic resin pigment powders for soft, matte tones and terrazzo effects. If you’re new, check out our guide on how to use acrylic resin.

• Shake liquids, sieve powders: Prevent clumps and ensure a uniform finish.

• Mind the clock: Work within the pot life; mix colour fully before pouring.

• Stay within ratio: As a rule of thumb, cap at ~2% pigment load.

Common uses include trays, coasters, planters, and decor where durable, fade-resistant colour is desired.

Colouring Jesmonite with Pigments

Jesmonite is a popular, water-mixable composite used for jewellery, homewares, and decor. For smooth, consistent tones, choose Jesmonite pigment or Jesmonite colour pigment specifically formulated for gypsum-acrylic systems.

• Test first: Make a small test to confirm hue and opacity before scaling.

• Build in layers: For marble, swirl, or terrazzo looks, pour in coloured sections or add coloured chips.

• Jewellery ready: For Jesmonite earrings and small pieces, use minimal pigment for crisp detail and faster sand-back.

If you’re colouring Jesmonite for statement hues, seal finished pieces to enhance depth and improve stain resistance.

Pigments for Plaster & Gypsum Resin

Plaster and gypsum-based mixes absorb colour differently than resin, often resulting in soft, chalky finishes unless sealed. Choose compatible pigments for plaster, gypsum plaster pigments, or plaster colour pigment to achieve even dispersion and predictable tones.

• Mix method: Pre-wet dry pigments or disperse in the liquid component before combining with powder.

• Surface sealing: A clear sealer boosts colour vibrancy and durability on plaster.

• Ratio discipline: Like resin systems, keep plaster pigment within sensible loading to maintain strength.

Tips for Mixing Pigments Successfully

• Weigh everything: Record total mix weight and pigment weight for repeatability.

• Start low, go slow: Add pigment gradually; it’s easier to deepen colour than to fix oversaturation.

• Disperse first: Blend pigment in a small portion of liquid, then reincorporate into the main batch.

• Defect control: Scrape cup walls and the mixing tool to prevent uncoloured streaks.

• Finish strong: Sand edges after cure; seal if you want higher colour pop and stain resistance—especially on plaster and gypsum composites.

Quick Workflow: Colouring ARC (Eco Resin)

1. Measure by weight: Prepare ARC at the recommended powder-to-liquid ratio.

2. Pre-tint: In a separate cup, disperse your eco resin pigment or eco resin powder into a small amount of liquid.

3. Combine & mix: Add tinted liquid to the main batch, keeping total pigment ≤ 2%.

4. Pour & cure: Degas by tapping the mould; allow to cure fully before demoulding and finishing. For best results, use high-quality silicone moulds for resin art.

   
   
   
   

Where to Find Compatible Pigments

For water-based acrylic casting systems, explore pigments designed for ARC and similar composites. They’re concentrated, easy to disperse, and formulated for stable colour across eco resin, Jesmonite, and plaster projects. Explore more resin art supplies at Just Resin.

Shop ARC Pigments and Casting Kits