Resin Exposure Test
Print your printer maker's exposure test with the resin you will use, starting from the resin's own profile for your printer. Under-exposed parts are soft or missing small features; over-exposed parts swell and fill in holes and gaps. Pick the exposure that forms the detail you need, set it as the normal (not bottom) exposure, and wear the gloves and eye protection the resin's SDS requires.
What the test measures
Exposure time is how long the light cures each layer. Anycubic explains both failure directions: too little exposure leaves the model under-cured, with soft surfaces, missing detail and visible layer lines; too much makes the model expand and lose dimensional accuracy, because resin is not fully transparent and light spreads into the surrounding resin. An exposure test prints a set of small features that show both effects, at several exposures or at one, so you can see where your resin sits.
The test is for the normal layer exposure. Bottom layers have their own, longer exposure for sticking to the build plate; see Resin Exposure Settings.
Read the safety data sheet for your resin before you open it. Formlabs' SDS for its Grey Resin, as one example, classes it as a skin sensitizer and eye irritant, calls for chemical-resistant gloves inspected before use and safety glasses or goggles, says to use it only with adequate ventilation and to wear a respirator if ventilation cannot keep vapor at an acceptable level, and says not to discharge it into public wastewater. Your resin's SDS may say more; follow it. Water-washable resin is never harmless, and never pour it or its wash water down a drain. See Resin PPE and Resin Waste and Disposal.
Prerequisites
- The resin maker's profile for your printer, if one exists. Use it as the starting exposure Starting point. There is no universal exposure value: it depends on the resin, the printer's light source and the layer height.
- The layer height you will print at. Test at the layer height you will print with; see Choosing a Layer Height for why exposure and layer height go together.
- A print that sticks. If prints fail at the plate or the film, fix that first: Resin Print Stuck to the Film.
- The test file made for your printer model. Anycubic says its R_E_R_F file is different for each printer model and must not be used on another.
How to run it
Anycubic: R_E_R_F (Resin Exposure Range Finder)
Anycubic printers recognize the file name R_E_R_F and switch on their exposure test mode, which prints eight numbered models at stepped exposures.
- Download the R_E_R_F file for your exact printer model from Anycubic's firmware and software page. Do not rename it, and do not give any other file that name.
- Copy it to a USB drive and insert it in the printer.
- Confirm or reset the exposure. Model 1 uses the normal exposure time you set, not the bottom exposure. Each following model adds a fixed increment that depends on the printer model (listed in its manual) and needs no setting.
- Print, then wash the parts and read the exposure from the number on each model.
Anycubic's example: with the starting exposure set to 1 s and a 0.25 s increment, the eight models run from 1 s to about 2.75 s, which brackets a recommended 2 s. Set model 1 below the resin maker's suggested value so the range brackets it.
Phrozen: XP Finder
Phrozen's XP Finder is a free test model with ten features. Open it in a slicer such as Chitubox or Lychee, select your resin and printer, slice and print. It prints at one exposure, so print it again at a different value to compare.
Other printers
Use the exposure test your printer or resin maker provides, and their instructions for reading it. Keep everything except the normal exposure the same between runs.
Reading the result
Wash the parts as your resin maker directs before judging them (see Washing and Curing). Anycubic's guidance: check whether every part formed and whether the details are clear. On curved surfaces, prefer the smoothest result; on holes and small pins, prefer the model with more holes open and more pins formed. Its own example shows the trade-off: one exposure keeps more holes open but risks failures, a longer one prints more reliably but bloats and loses detail.
| Feature on the XP Finder | Under-exposed | Over-exposed |
|---|---|---|
| Text | Parts of letters missing or faint | The dot of the "i" merges with its stroke |
| 13 pillars | Smaller pillars missing or barely raised | Pillars look bigger, gaps uneven |
| 14 side panels | Edge panels missing | Panels merge |
| Thin frame line | Line missing | Nearby boards merge |
| Logo | Thin lines, large blank center | Lines merge and fill the center hole |
If none of the exposures look right, Anycubic says to change the starting exposure and run the test again.
What to change
Set the chosen value as the normal layer exposure in your slicer's resin profile. Phrozen recommends going above the test result for real prints: at least 10 percent more for an actual model, and up to 20 percent more for models over 12 cm Rule of thumb, to help adhesion and full curing. Then print one real part before committing a full plate.
Leave these alone during the test
- Bottom exposure and bottom layer count. They affect sticking, not the detail you are judging.
- Layer height, lift and retract settings, and the resin's profile otherwise.
- The resin itself: shake or stir it as the maker says, and test with the bottle you will print from.
If layers split or peel apart after you change exposure, see Resin Layer Separation.
- Resin 3D Printer: Guide for testing optimal exposure time Anycubic
- 10 XP Finder Secrets That You Might've Missed Phrozen
- Safety Data Sheet: Grey Resin (FLGPGR04) Formlabs
Last reviewed 2026-11-05