Anycubic Resin Exposure Time Settings Explained

A Photon profile is a handful of numbers the printer applies in a fixed order: a long bottom exposure for the first layers, an optional ramp of transition layers, then the normal exposure that runs for the remaining thousands. This is Anycubic resin exposure time settings explained in that order, from the definitions on Anycubic’s wiki, its per-printer resin tables, and the R_E_R_F test file. The short version: Anycubic resin on a mono-LCD Photon wants about 2 to 3 s per 0.05 mm layer, a bottom exposure roughly ten times that, and a retest whenever the resin, the room or the screen changes.

What each setting does, in the order the printer applies it

Layer thickness. The wiki’s range is 0.01 to 0.15 mm with a 0.05 mm default. Thinner layers cure with less exposure; thicker ones need more, which the wiki notes ages the LCD faster. Everything below assumes 0.05 mm unless stated.

Bottom exposure and bottom layers. The first layers cure against a metal plate, not cured resin, so they get a far longer exposure: around 40 s on a brushed (“wire drawing”) platform and around 25 s on a laser-engraved one, with about 6 bottom layers, adjusted for model size and contact area. Too long and the base swells into an elephant foot. Which side of that line a failure sits on is the first question in the resin sticking to the FEP guide.

Transition layers. The Photon Workshop manual defines the count as “the transition layers between the bottom layers and normal layers”; Chitubox ramps them linearly, the only transition type it supports. They remove the cliff between a 25 s layer and a 2.8 s layer, which is where a print splits just above its base.

Normal exposure. Generally 2 to 3 s for Anycubic resin, per the wiki. Too short and the model is soft, loses detail and shows layer lines. Too long and it expands, because the resin is not fully transparent and UV diffuses into the surrounding liquid. Dark resins block more light and need a little more.

Off time. The interval between the platform finishing its descent and the next exposure. The wiki recommends 1 to 3 s, longer for viscous or cold resin and large layer areas, though its own tables use 0.5 s for standard resin on most current machines.

Why the numbers land where they do

Exposure is a dose. A NIST-led interlaboratory study uses the standard working curve, cure depth = Dp ln(E0/Ec), where Dp is the resin’s light penetration depth and Ec the dose at which it gels. Cure depth grows with the logarithm of the dose, so the first second does most of the work and each extra second buys little depth while still spreading light sideways in XY and down into the resin under overhangs. That is where closed holes, filled text and blunted downward-facing detail come from. Dp and Ec belong to the formulation, so every bottle is its own curve; the resin types comparison covers them by family.

Temperature moves the curve too. The wiki puts the optimal resin temperature around 24 °C and says it will not cure properly below 10 °C. Its resin settings page is specific: below 20 °C, raise exposure by 30% and cut Z speeds by 30%. Its values also assume factory light energy, so a machine with adjustable UV power needs its own retest.

AmeraLabs’ calibration primer covers the rest: the rule of thumb “50% lower layer height = 25% lower exposure”, bottom exposure around ten times the normal layer, and a recalibration every 3 to 6 months because the light source decays.

Anycubic’s own numbers by printer

Standard Resin at 0.05 mm, from the wiki’s tables:

Bottom layer counts run from 1 to 6 across Anycubic’s own machines, so “about 6” is a starting point, not a rule. High Speed Resin is a different row, not a shorter exposure: on the Mono 4 Ultra it is 1.8 s at 0.1 mm layers, 15 s bottom and a 20 mm/s lift; on the M5s it is 1.7 s, 10 s bottom, 3 bottom layers and a 3 mm lift at 20 mm/s. Changing the resin without the rest of the row is how fast resin usually fails.

Anycubic RERF: how to use the R_E_R_F exposure test

Anycubic RERF means Resin Exposure Range Finder. Use the model-specific file from the supplied USB drive or the manufacturer’s downloads, as described in Anycubic’s RERF instructions. Keep the filename R_E_R_F; do not give that name to an ordinary print or reuse another printer’s test file. The increment is a printer-specific value, not a universal 0.25 s setting.

The Resin Exposure Range Finder prints eight numbered models in one job. Model 1 uses the normal exposure from the slice, not the bottom exposure, and each following model adds a fixed increment the wiki calls “Ts”, set per machine and printed in its manual. The file must keep the name R_E_R_F and is different for every printer model. Set model 1 below the value you expect so the answer lands mid-range: with a recommended 2 s and a 0.25 s step, start at 1 s and the eight models span 1 to 2.75 s.

Judge by Anycubic’s criteria. On curved parts the smoothest surface wins. On the hole and pin features, count both: many holes and few pins means the exposure sits between optimal and failure, more detail at more risk; few holes and many pins means bloat, reliable but blunt. If none of the eight is right, shift model 1 and run again.

The exposure for numbered model n is model 1 exposure + (n - 1) × Ts. In the 1 s / 0.25 s example above, models 1, 4 and 8 receive 1 s, 1.75 s and 2.75 s respectively. Record the winning model’s calculated exposure with the resin, layer height and printer profile; recording only its number loses the setting when the starting exposure changes.

Confirm the result with a separate calibration part

Confirm with a resin-agnostic part. The AmeraLabs Town prints at 50 µm in about 30 minutes: a weak antenna and fewer pillar rows mean under-exposure, narrow checkerboard gaps and an enlarged raised logo mean over-exposure. The UVtools resin time finder runs from the sliced file rather than the firmware and defines “just right” usefully: features match the preview, spacings hold, and the smallest single-pixel features are missing. It also advises raising bottom exposure for the test plate, from 30 s to 40 to 50 s, so a long row of parts stays put. The calibration walkthrough on resinprintguide.com reads these tests in more depth.

A worked profile and what to change when

Photon Mono M5s, Anycubic Standard Resin, 0.05 mm: 2.8 s exposure, 0.5 s off time, 25 s bottom, 5 bottom layers, 8 mm lift at 6 mm/s, 6 mm/s retract. In a room under 20 °C the wiki’s 30% rule gives 3.6 s, 32.5 s bottom and 4.2 mm/s. Then run R_E_R_F from 2 s and let the print pick the number.

Splits that survive these changes belong to peel force or temperature, which the layer separation guide on resinprintguide.com works through in test order.