Resin Printing Glossary: Terms Every Hobbyist Should Know

Resin printing has a vocabulary problem. Guides throw out terms like “FEP,” “suction cupping,” and “green state” on the assumption you already know what they mean. Forums are worse. If you’re new, you spend half your time chasing definitions instead of actually printing.

This page collects the terms that show up constantly across our guides and gives you plain-language definitions. Nothing Wikipedia-style here. These are the words the way someone who learned them the hard way would explain them to a friend.

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Printer Hardware

FEP Film

The thin, transparent film stretched across the bottom of the resin vat. When the UV screen cures a layer of resin, the FEP releases it from the vat floor so the build plate can lift. Think of it as a non-stick layer: except it’s not permanent. FEP degrades over time, scratches if you scrape it with a metal tool, and goes cloudy when it starts to fail. A cloudy or scratched FEP is behind more unexplained print failures than almost anything else. Replace it on a schedule, not just when things break.

MSLA (Masked Stereolithography Apparatus)

The printer type you almost certainly own if you’re printing miniatures. MSLA printers use a UV LCD screen to cure an entire layer of resin at once by projecting the layer pattern through a mask. Most consumer resin printers (Elegoo Saturn, Anycubic Photon, Phrozen Sonic) are MSLA. It’s why they print so much faster than older SLA printers, which cured resin point-by-point with a laser.

LCD Screen vs. MSLA

The terms get mixed up but they’re describing the same thing from different angles. The LCD is the actual component inside an MSLA printer: the screen that projects each layer pattern. When a printer is called “monochrome” or “mono,” that refers to its LCD type. Monochrome LCDs transmit more UV light than color LCDs did, which is why modern mono printers have shorter exposure times and longer screen lifespans. If your printer was made after 2020, it almost certainly has a monochrome LCD.

Build Plate

The metal plate your print attaches to. It lifts up layer by layer as the print builds from the bottom of the vat upward. Leveling it correctly before every print session is the most important maintenance task in resin printing. A build plate that’s even a fraction of a millimeter too far from the FEP means the first layers cure on the film instead of the plate, and nothing will stick. You will find a disc of cured resin at the bottom of your vat and nothing on the plate. That’s a leveling problem nine times out of ten.

Vat

The resin reservoir that sits between the build plate and the UV screen. It holds your liquid resin and has the FEP film stretched across its floor. The vat also collects debris from failed prints: always strain your resin back through a paint strainer when checking for fragments after a failure. Cured resin chunks sitting in the vat will scratch the FEP and ruin subsequent prints.

XY Resolution / Pixel Pitch

The size of each individual pixel on the UV screen, measured in microns (µm). A 4K printer like the original Elegoo Saturn has a 50µm pixel pitch, meaning each pixel is 50 microns wide. Smaller pixel pitch means finer detail capability. A printer with pixels in the 14–24µm range (9K to 16K) resolves significantly sharper surface detail than a 4K printer, especially on faces, scale mail, and fine scroll work. For 28-32mm miniatures, the difference is visible but not enormous. For 15mm scale or display pieces where you’re photographing at 2x, it matters more.

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Slicing and Print Settings

Slicer

The software that converts a 3D model file into print instructions the printer can execute. You import your STL or OBJ file, orient the model, add supports, configure settings, and the slicer outputs a file your printer reads. The two slicers most hobbyists use are Lychee and Chitubox. The slicer is where most print problems originate: wrong settings, missed support placement, or bad orientation. Getting comfortable in your slicer is more valuable than upgrading your printer.

Layer Height

How thick each individual layer of resin is, measured in millimeters. Thinner layers produce smoother surfaces and finer detail, but longer print times. For miniatures, 0.05mm (50 microns) is the standard for infantry and everyday work. Drop to 0.03mm for display pieces or named characters where you want the cleanest possible surface on faces and curved armor. Going thinner than 0.03mm is rarely practical for tabletop work: print time increases significantly without much visible benefit at typical viewing distance.

Exposure Time

How long the UV screen lights up to cure each layer, measured in seconds. Too short and layers don’t cure fully: you get weak prints, layer separation, and features that fall apart. Too long and adjacent geometry fuses together, faces look melted, and detail is lost. There is no universal correct exposure time. It varies by printer model, resin brand, resin age, room temperature, and FEP condition. Run a calibration print when you start a new bottle of resin, not just when prints start failing.

Bottom Exposure Time

The extended exposure time applied to the first several layers: the ones that fuse the print to the build plate. Usually 5-10x longer than normal exposure, often 30-60 seconds. These layers need more UV to create a strong adhesion bond with the plate surface. Too short and the raft pulls off the plate mid-print. Too long and the raft welds itself to the plate so hard you can damage the surface coating trying to remove it. Getting this number right is most of what “dialing in” a new resin means.

Anti-Aliasing (AA)

A setting that smooths the edges of each cured layer by partially exposing the pixels along the boundary. Without it, curved surfaces have a visible staircase pattern from layer to layer. With it, those edges blend more smoothly. The tradeoff is that aggressive anti-aliasing can soften very fine detail, so the right level depends on your printer’s native resolution. On 4K printers, AA makes a noticeable difference on curved faces and round armor. On 12K and higher, the native resolution is already fine enough that the difference is minimal.

Calibration Print

A small test file designed to tell you exactly where your exposure time needs to land for a specific printer-and-resin combination. The Ameralabs Town and Validation Matrix files are common ones. They print in 30-45 minutes and show you whether you’re over-exposed (features are merging), under-exposed (features are weak or missing), or dialed in. Run one when you open a new bottle of resin, switch resin brands, or start seeing unusual failures. It’s 30 minutes and a small amount of resin versus hours of failed prints and a ruined plate of miniatures.

Peel Force / Light-Off Delay

Every time a layer cures, the build plate lifts to peel the cured layer from the FEP. That lift creates a force: stronger on larger flat layers, weaker on small detailed ones. Light-off delay is a pause you can add between the cure cycle and the next layer lift. Even 0.5-1.0 seconds of delay lets the layer solidify more completely before the peel stress is applied. It’s a simple setting that reduces mid-print failures, especially on large terrain pieces, creature models, and anything with wide flat sections.

TSMC (Two-Stage Motion Control)

A peel movement pattern available on many modern MSLA printers. Instead of one continuous lift movement per layer, TSMC splits the lift into a slow initial peel (which reduces the force spike at the moment the FEP releases) followed by a faster continuation lift. For miniatures it’s almost purely upside: slower peel at the moment of release means less stress on supports and thin features. If your printer supports it, enable it and leave the default values alone until you have a reason to change them.

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Supports and Rafts

Raft

A flat printed base beneath your model and its supports. The raft is what actually bonds to the build plate surface: your model isn’t directly touching the plate. A properly sized raft distributes the peel force across a wider area and makes removal cleaner than printing directly on the plate. Set raft thickness to 1.5-2mm for most prints. Thinner and it tears during removal; thicker and you’re wasting resin without benefit.

Supports

Thin printed columns that hold parts of the model in place during printing. Because MSLA printers build from the bottom up, any part of the model that doesn’t have something below it will fail. Supports connect those floating sections to the raft or to other supported geometry. Support placement is where most miniature print failures actually originate, not exposure, not resin quality, not the printer. Too few supports in the wrong places and you’ll find a partial model or a failed plate every time.

Support Islands

Sections of the model that appear in the slicer layer preview without anything below them. An island means that layer of the model will attempt to cure in liquid resin with nothing to hold it. It will fail, or worse, it will partially adhere to the FEP and get dragged around for the rest of the print. Every slicer can detect islands. Your goal before slicing is zero detected islands. If the slicer flags any, add a support to that section before you print.

Pre-Supported STL

A model file that already has supports and orientation added by the creator before you download it. You import it into your slicer and it arrives ready to slice and print, though you should still review the slice preview. Pre-supported files save setup time but aren’t always optimized for your specific printer or resin. For subscription miniatures from professional creators, pre-supported files are standard. For free files, you usually support them yourself.

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Resin and Chemistry

Resin Shrinkage

Photopolymer resin shrinks slightly as it cures (the UV reaction causes the molecules to pull together. This is why warping happens on large flat prints: bottom layers cure first and shrink, pulling the part. Standard resins shrink more than ABS-like or flexible resins, which is why flat terrain and large bases warp more with standard resin. Tilting flat prints at an angle during printing is the most reliable way to manage shrinkage) no single layer becomes a large flat surface that can curl.

IPA Wash

Isopropyl alcohol used to clean uncured resin off a freshly printed model. After the print comes off the build plate, it’s coated in liquid resin. Submerging it in IPA (90% or higher) and agitating for 2-5 minutes dissolves and removes the uncured residue. The washed print is still fragile: this is the green state, before UV post-cure. Do not skip the wash. Do not use IPA with uncured resin particulate to wash food containers or drains. Cure the used IPA in sunlight first, then dispose.

VOCs (Volatile Organic Compounds)

The chemicals that off-gas from liquid resin during printing and from IPA during washing. You can smell them: that’s not the only sign they’re present, but it’s a consistent one. VOC exposure is manageable with ventilation: a window open and a fan drawing air out of the room handles the vast majority of hobbyist-level printing. Printing overnight in a sealed bedroom with no ventilation is not manageable. A carbon filter air purifier adds another layer of protection if you print frequently.

Cure Time

The amount of UV exposure needed after washing to harden the print fully. Post-cure happens after the IPA wash step, under a dedicated UV station or UV lamp. Most resins need 2-4 minutes under a cure station at 405nm. Over-cure makes the print brittle: you will snap thin features on removal. Under-cure leaves the surface tacky and the model chemically unstable. Check the resin manufacturer’s recommendation and start there. A properly cured print should be hard, matte, and not tacky to the touch.

Post-Cure

The UV curing step you run after washing, not during printing. The printer cures each layer enough to hold its shape, but the print that comes off the build plate is still partially polymerized: the green state. Post-cure completes the reaction, hardens the material to full strength, and stabilizes the surface chemistry. Remove all your supports before post-cure. In the green state, supports snap away cleanly. After post-cure, removing supports risks snapping the model surface off along with them.

Green State

What the print is between the wash and the post-cure. The resin is partially cured: hard enough to hold its shape, soft enough to be flexible. The green state is when you remove supports, fix any minor surface issues with a hobby knife, and make any small adjustments before the final cure locks everything in permanently. A useful window. Don’t rush through it by curing immediately off the plate.

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Print Failures

Delamination

When layers of the print separate from each other rather than bonding into a solid part. You’ll see it as visible gaps or horizontal cracks in the model. The cause is almost always under-exposure: adjacent layers didn’t cure enough to form strong bonds between them. The fix is increasing normal exposure time. A damaged or cloudy FEP can also cause delamination by scattering the UV light before it reaches the resin, reducing effective dose even with correct exposure settings.

Suction Cupping

A failure mode where a large flat section of the model creates a vacuum seal against the FEP during the peel cycle. Instead of peeling away progressively, the entire surface releases at once, generating a force spike that either pulls the print off the build plate or deforms the model. Terrain, large bases, and multi-model plates are most vulnerable. The fixes are: tilting large flat prints at an angle, enabling light-off delay, and using a perforated or anti-suction raft option if your slicer supports it.

Hollowing

The process of making a solid model into a shell to save resin. A solid 60mm monster might use 4-5x the resin of the same model hollowed to a 2mm shell. Most slicers have a hollow tool. The catch that trips up beginners: a hollowed model with no drain holes is a trap. Uncured liquid resin gets sealed inside. It cures slowly over months, expands as it does, and eventually cracks the shell open. Always add at least two drain holes, positioned so liquid can escape during the wash step.

Drainage Holes

Small holes cut into a hollowed model to let uncured resin flow out during washing. Without them, liquid resin is sealed inside the print. Position drain holes at the lowest points of the model when it’s oriented for printing: that way gravity works in your favor during the wash. Two holes minimum; three is better for complex shapes with multiple low points. The holes can usually be hidden on the underside of a base or inside a cloak or shield back where they won’t show on the finished piece.

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Painting and Finishing (Terms Referenced in Print Guides)

PPE (Personal Protective Equipment)

Nitrile gloves, safety glasses, and a respirator or active ventilation. These are not optional for resin printing. Uncured resin is a skin sensitizer: repeated exposure without protection doesn’t cause a reaction right away, but sensitization builds over time. Once you’re sensitized to resin, even small exposures cause reactions that worsen with each subsequent contact. There’s no unsensitizing. Prevention is the entire strategy. Gloves on before the session starts, every session.

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Most of these terms come up in the complete beginner’s guide to resin printing, the troubleshooting guide, and the supports guide. When a guide uses a term from this page, it will link back here on first use.

If you’re seeing a term in one of our guides or in a forum discussion that isn’t defined here, let us know via the contact page and we’ll add it.