Abstract: The present invention includes methods for forming an object in a volume including a photohardenable composition described herein that includes a photohardenable resin component and a photoswitchable photoinitiator comprising a P-type photochromic molecule. The present invention also includes photoswitchable photoinitiators comprising a P-type photochromic molecule, preferably comprising a P-type diarylethene molecule, and photohardenable compositions and methods including such photoswitchable photoinitiators.

Abstract: The present invention relates to the technical field of light sheet technology and related methods and apparatuses including light sheet technology for use in three-dimensional printing. The present invention includes methods and apparatuses including a combined light sheet including, for example, methods for improving light intensity uniformity of a light sheet including a first wavelength passing through a composition and methods of forming an object in a volume, which methods include a combined light sheet comprising a generated light sheet and reflected light sheet, and related apparatuses.

Abstract: Photohardenable compositions comprising a photohardenable component and a photoswitchable photoinitiator, wherein the photoswitchable photoinitiator is activatable by exposure to light having a first wavelength and light having a second wavelength to induce a crosslinking or polymerization reaction in the photohardenable component, and wherein the photohardenable composition displays non-Newtonian rheological behavior are disclosed. Methods including such photohardenable compositions for printing one or more objects are also disclosed.

Abstract: A stabilizer for inclusion in a photohardenable composition comprising a hardenable resin component and a photoinitiator, the stabilizer comprising a stable free radical functionalized polymer, wherein the stabilizer is dispersible or dissolvable in the hardenable resin component. A photohardenable composition including a hardenable resin component, a photoinitiator, and a stabilizer comprising a stable free radical functionalized polymer and methods including a photohardenable composition and products of the methods are also disclosed. A photohardenable composition can further include an upconverting component.

Abstract: Photoswitchable photoinitiators comprising a naphthopyran molecule including one or more substituents wherein at least one substituent comprises a substituted or unsubstituted diaryl ketone moiety are disclosed. Photohardenable compositions and methods for forming an object in a volume and products thereof, which photohardenable compositions and methods include such photoswitchable photoinitiator, are also disclosed.

Abstract: A method for printing a three-dimensional object in a volume of a photopolymerizable liquid by photopolymerization, the method comprising: (a) providing a digital representation of a three-dimensional object that has been sliced into a plurality of sequential two-dimensional image slices along the z-direction; (b) processing each of the two-dimensional slices of the three-dimensional object into a sequence of subsampled images, each subsampled image comprising an arrangement of pixels wherein each pixel has defined x and y dimensions; (c) sequentially exposing each of the sequence of subsampled images of a slice at a selected location along the z-direction in the volume using excitation light until the volume at the selected location along the z-direction has been exposed to all of the subsampled images of the slice, and (d) sequentially repeating step (c) for a previously unexposed sequential slice of the three-dimensional object, each at different selected location along the z-direction, until the three-dim