I'm new to oil painting with four paintings under my belt. Trying to paint one of my photo of sunset over the ocean. I want to paint a realistic sky that has a blue sky blend into the deep orange sunset over the horizon. My problem is that when the blue color blend with yellow it creates a "greenish" color, which is not the color of the sunset. The photo shows the sunset is a deep orange to light yellow blend to light blue and then to dark blue. No problem with mixing orange to yellow and light blue to dark blue. Base on the color wheel blue mix yellow is green but that is not what I see in nature. Any suggestions how to mix the yellow to blue transition and remain without a greenish color.