This disclosure describes hydrogel three-dimensional printing kits, methods of three-dimensional printing hydrogels, and hydrogel three-dimensional printing systems. In one example, a hydrogel three-dimensional printing kit can include a particulate build material, a crosslinking agent, a whitening agent, and a coloring agent. The particulate build material can include a polyhydroxylated swellable polymer. The crosslinking agent can include water and a crosslinker that is reactive with hydroxyl groups of the polyhydroxylated swellable polymer to crosslink the polyhydroxylated swellable polymer. The whitening agent can include water and a dispersed white pigment. The coloring agent can include water and a colorant.

This disclosure describes hydrogel three-dimensional printing kits, methods of three-dimensional printing hydrogels, and hydrogel three-dimensional printing systems. In one example, a hydrogel three-dimensional printing kit can include a particulate build material, a crosslinking agent, a whitening agent, and a coloring agent. The particulate build material can include a polyhydroxylated swellable polymer. The crosslinking agent can include water and a crosslinker that is reactive with hydroxyl groups of the polyhydroxylated swellable polymer to crosslink the polyhydroxylated swellable polymer. The whitening agent can include water and a dispersed white pigment. The coloring agent can include water and a colorant.

There are provided a compound represented by general formula (1), a photopolymerization initiator comprising this compound, a photocurable composition having this photopolymerization initiator and a photocurable compound as essential components, and a cured product formed by curing this photocurable composition, wherein in formula (1), R.sup.1 and R.sup.2 each independently represents an alkyl group or the like; R.sup.3 to R.sup.5 each independently represent a hydrogen atom, an alkyl group or the like; X.sup.1 represents a single bond or an alkylene group; and X.sup.2 represents a bonding group represented by general formulas (2) to (4), and wherein n represents an integer of 1 to 6, when n is an integer of 1, Y represents an alkyl group, an aryl group or the like.

There are provided a compound represented by general formula (1), a photopolymerization initiator comprising this compound, a photocurable composition having this photopolymerization initiator and a photocurable compound as essential components, and a cured product formed by curing this photocurable composition, wherein in formula (1), R.sup.1 and R.sup.2 each independently represents an alkyl group or the like; R.sup.3 to R.sup.5 each independently represent a hydrogen atom, an alkyl group or the like; X.sup.1 represents a single bond or an alkylene group; and X.sup.2 represents a bonding group represented by general formulas (2) to (4), and wherein n represents an integer of 1 to 6, when n is an integer of 1, Y represents an alkyl group, an aryl group or the like.

A recording method includes: recording a first image on a recording medium; reading the first image to determine whether the first image is correctly recorded; and when the first image is determined as not being correctly recorded, recording a second image over the first image. The water-based recording ink includes a water-soluble organic solvent which is at least one selected from the group consisting of a glycol ether and a diol compound having six to eight carbon atoms and two hydroxyl groups, at least one of the two hydroxyl groups not being bonded to a terminal of a carbon chain of the diol compound. A content of substances having a vapor pressure of 0.03 hPa or less at 20° C. in the water-based recording ink is 10 mass % or less and a surface tension of the water-based recording ink is 30 mN/m or less.

A display panel and a display apparatus are provided. A display region of the display panel includes a first display region and a second display region located between the first display region and the non-display region. The light-emitting device layer includes light-emitting devices which includes a first light-emitting device and a second light-emitting device. Light-blocking structures are located on a side of the light-emitting device layer away from the substrate and include a first light-blocking structure and a second light-blocking structure. The first light-blocking structure is adjacent to the first light-emitting device, and the second light-blocking structure is adjacent to the second light-emitting device. The first light-blocking structure has a greater thickness or height than the second light-blocking structure. The present disclosure can balance the brightness difference caused by different viewing angles at different display regions, improving visually uneven brightness and visual effect.

A cleaning liquid contains water, a surfactant, and glycol ether. The surfactant includes both a silicone surfactant and a betaine surfactant. The glycol ether has a percentage content of at least 5.0% by mass and no greater than 15.0% by mass relative to the mass of the cleaning liquid. The cleaning liquid has a viscosity at 25° C. of 10.0 mPa.Math.s.

A cleaning liquid contains water, a surfactant, and glycol ether. The surfactant includes both a silicone surfactant and a betaine surfactant. The glycol ether has a percentage content of at least 5.0% by mass and no greater than 15.0% by mass relative to the mass of the cleaning liquid. The cleaning liquid has a viscosity at 25° C. of 10.0 mPa.Math.s.

An ink jet ink composition includes water, a phospholipid that forms a fine particle, and a coloring material that is incorporated in the fine particle.

An ink jet ink composition includes water, a phospholipid that forms a fine particle, and a coloring material that is incorporated in the fine particle.