A double coating, comprising: a substrate; a first layer comprising a first low-temperature cure coating composition, which is a polar composition comprising: a first hydroxy-functional resin, an aminoplast resin low-temperature crosslinking agent, at least one non-polar catalyst, and a solvent and a second layer comprising a second low-temperature cure coating composition, which is a non-polar composition comprising: a second hydroxy-functional resin, a second low-temperature crosslinking agent, which is an optionally-blocked isocyanate resin, at least one polar catalyst, and an organic solvent, wherein the first layer and the second layer are in direct contact with each other, wherein the at least one non-polar catalyst catalyzes a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, wherein the at least one polar catalyst catalyzes a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent. a substrate; a first layer comprising a first low-temperature cure coating composition, which is a polar composition comprising: a first hydroxy-functional resin, an aminoplast resin low-temperature crosslinking agent, at least one non-polar catalyst, and a solvent and a second layer comprising a second low-temperature cure coating composition, which is a non-polar composition comprising: a second hydroxy-functional resin, a second low-temperature crosslinking agent, which is an optionally-blocked isocyanate resin, at least one polar catalyst, and an organic solvent, wherein the first layer and the second layer are in direct contact with each other, wherein the at least one non-polar catalyst catalyzes a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, wherein the at least one polar catalyst catalyzes a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent. a first hydroxy-functional resin, an aminoplast resin low-temperature crosslinking agent, at least one non-polar catalyst, and a solvent and a second layer comprising a second low-temperature cure coating composition, which is a non-polar composition comprising: a second hydroxy-functional resin, a second low-temperature crosslinking agent, which is an optionally-blocked isocyanate resin, at least one polar catalyst, and an organic solvent, wherein the first layer and the second layer are in direct contact with each other, wherein the at least one non-polar catalyst catalyzes a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, wherein the at least one polar catalyst catalyzes a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent. a second hydroxy-functional resin, a second low-temperature crosslinking agent, which is an optionally-blocked isocyanate resin, at least one polar catalyst, and an organic solvent, wherein the first layer and the second layer are in direct contact with each other, wherein the at least one non-polar catalyst catalyzes a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, wherein the at least one polar catalyst catalyzes a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent. wherein the first layer and the second layer are in direct contact with each other, wherein the at least one non-polar catalyst catalyzes a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, wherein the at least one polar catalyst catalyzes a crosslinking reaction between the first hydroxy-functional resin and the aminoplast resin low-temperature crosslinking agent, and does not catalyze a crosslinking reaction between the second hydroxy-functional resin and the second low-temperature crosslinking agent.