3D printing with resin allows for incredibly detailed and smooth prints, but getting the colors just right can be tricky. Unlike filament printing where you simply change the spool, coloring resin requires adding pigments or dyes to the clear photopolymer resin. There are a few different methods for coloring resin and achieving vibrant, accurate colors for your 3D printed objects.
Choosing Colored Resin
The easiest way to get colored 3D prints from resin is to purchase pre-colored or pigmented resin. Many resin manufacturers like Anycubic, SirayaTech, and Elegoo carry a range of colored resins to choose from. The pigments are mixed directly into the resin so all you need to do is pour the resin into the vat and print as normal. Pre-colored resins allow for consistent, predictable colors and require no extra steps, but the selection is limited to what colors are pre-mixed.
Coloring Resin with Pigment
For a wider range of color options, you can tint regular clear photocuring resin yourself with pigments. Pigments are concentrated powdered color additives that permanently color the resin. A little bit of pigment goes a long way in coloring resin. This method allows you to mix custom colors.
Here are some tips for coloring resin with pigments:
- Use a very small amount of pigment starting around 1% ratio by weight. Too much can inhibit curing.
- Mix the pigment into a small amount of resin first to make a concentrated colorant, then add to the larger resin volume.
- Thoroughly mix the pigment concentrate into the resin to disperse the color evenly.
- matching Pantone colors, use artist grade pigments for the truest color representations.
- Test colors on a print prior to a full print. It may take some trial and error to achieve the exact desired shade.
- Allow for potentially longer print times as pigments can slow curing speed.
Pigment concentrates made specifically for resin 3D printing take the guesswork out of ratios and mixing. Brands like Jacquard Pigment, Let’s Resin, and Pro Marine Supplies sell pigment mixes that you simply add by the drop into clear resins.
Using Resin Dyes
Another option for coloring resin is to use liquid dye concentrates. These work similarly to pigments but are less concentrated and require more volume to achieve rich colors. However, dyes mix easily into resins and are less likely to inhibit curing.
Good resin dyes to try are alcohol inks, resin tints, and food coloring dyes without citric acid. Start with a few drops per ounce of resin. Stir well to fully dissolve and distribute the dye. Unlike pigments, dyes will remain transparent for a stained glass effect.
Painting 3D Printed Resin
For small details, accents, or color corrections, you can paint cured resin prints. Thin layers of acrylic paint work well for adding color. Make sure to seal painted prints so the paint doesn’t chip or rub off over time. Some good sealants are matte varnish, epoxy resin, or a clear coat spray paint.
When painting 3D prints:
- Lightly sand the surfaces first to help paint adhere better.
- Apply paint in thin layers, allowing it to dry between coats.
- Use an art paintbrush and acrylic paints.
- Look for dedicated miniatures or model paints for small details.
- Seal when done painting for a protective finish.
Achieving Optical Clarity
One of the advantages of resin printing is achieving optically clear prints that look like glass. This works best with transparent colorless resin. Any additives will reduce clarity to some degree. For maximum clarity:
- Use the clearest photopolymer resin formulation you can find.
- Ensure the resin is mixed thoroughly to prevent any bubbles or haziness.
- Allow the print to fully cure in UV light for the recommended time.
- Let prints soak in isopropyl alcohol to remove any remaining sticky resin.
- Rinse well and let dry fully before polishing or sealing.
Considerations for Multicolor Prints
Making full color models requires either painting by hand or splitting the model into separate pieces to print in different colors. Plan multicolor prints in advance:
- Design the 3D model in segments that align to color divides.
- Print each segment in a different colored resin.
- Glue assembled segments together using acrylic resin.
- Sand and prime before painting to help bond segments.
- Consider using a dual extrusion mixing nozzle for gradient blends.
Cleaning Colored Resin Prints
Removing leftover wet resin after printing requires extra care with pigmented or dyed resins. The color may bleed when washed in isopropyl alcohol leaving prints tinted. To avoid color transfer:
- Submerge prints in clean IPA wash and do not reuse it.
- Agitate gently to prevent rubbing color off prints.
- Change the IPA bath frequently to limit color contamination.
- Rinse thoroughly with clean IPA until water runs clear.
- Allow prints to air dry fully before further handling or curing.
Curing Colored Prints
Pigments and dyes can slow down the photopolymer curing time. To ensure full curing:
- Cure resin prints 5-10% longer than the resin manufacturer recommends.
- Rotate the print frequently under UV light to hit all surfaces.
- Check prints for any tackiness that indicates additional curing is needed.
- Use a higher power UV curing lamp for faster curing.
Achieving Consistent Color
Getting consistent colors across multiple resin prints requires controlling variability in the coloring process. Here are some tips for color consistency:
- Thoroughly mix resin colorants each time and use precise measuring tools.
- Shake or stir pigment concentrates before each use.
- Store unused colored resin in opaque containers out of light.
- Maintain a consistent print environment and resin curing time.
- Use the same ratio of colorant to resin for multiple batches.
Test new resin colors extensively before committing to a full print. Environmental factors and print settings impact final color.
Troubleshooting Resin Print Colors
| Issue | Potential Causes | Solutions |
|---|---|---|
| Faded or dull colors | Insufficient pigment or dye ratio, Resin not fully cured, Resin expired | Increase amount of colorant, Cure longer under UV, Use fresh resin |
| Bleeding or muddy colors | Too much dye or pigment ratio, Incomplete wash and rinse | Reduce amount of colorant, Change IPA wash frequently, Rinse thoroughly |
| Inconsistent colors | Uneven mixing of pigment/dye, Resin curing issues, Environment changes | Mix thoroughly before each print, Control curing conditions, Maintain stable environment |
Conclusion
Coloring resin for 3D printing takes some experimentation but opens up exciting possibilities for vibrant models and miniatures. Pre-mixed pigmented resin provides the easiest option while dyes and pigments allow for custom color mixing. Maintain strict control over the coloring process and curing conditions to achieve consistent, reliable colors. With a little practice, you can master achieving any desired shade and optical clarity on your printed resin objects.
