How to change PLA filament colors between prints

Black filament out, white filament in, and the first extrusion is an uninvited shade of gray. A color swap needs a little housekeeping. Clear the previous material, secure the old spool, and check a small sample before committing to the next model.

Unload with the printer's routine

Follow the load and unload instructions for your machine. Use its guided routine where available, including the specified temperature and any filament cutting step. Do not pull against a cold hotend or force filament through an obstruction.

As the old filament comes free, keep hold of the end and secure it through the spool's retaining hole or a suitable clip. Put the spool in its labeled storage container. This is easier to do immediately than after the loose end has slipped into the winding. Future you has enough unfinished prints to deal with.

Load and inspect the extrusion

Check that the new spool rotates freely and that the filament follows the intended path. Use the printer's purge or extrusion function until the output has changed to the new color. The amount needed varies with the hotend and color combination, so a fixed purge length is not a reliable rule for every printer.

Keep hands away from moving and heated components, and use the manufacturer's method to remove purge waste. Watch for interrupted extrusion or material collecting on the nozzle before starting a model.

Print a small color check

Use a sample with a flat face and any lettering the final part needs. This is particularly useful when moving to White or Natural after Black. Inspect it under the lighting where the finished part will be used.

Save a note with the old and new colors, profile, and result. If the color looks wrong only at the beginning, that record can help separate leftover material from a lighting or color-selection issue.

Changing color during a print

A mid-print swap is a separate workflow. Use a pause or color-change function supported by your printer and slicer, then inspect the layer preview before sending the file. Keep the materials compatible; a PLA-to-PETG swap is not the same as changing between PLA colors.

Reference: PrusaSlicer's color-change documentation. For selecting a pair of colors, see our PLA color guide; for storage, see putting an opened spool away.