My Outdoor Painting Palette

My plein air painting palette 

Life Needs Art follower Mike Blake recently asked the following question: 

"What would you say the core ABSOLUTELY necessary colors are when painting outside?  I have a hard time getting vibrant natural colors...thanks." 

I am not an expert in outdoor painting, since I have have really only been seriously pursuing it for about a year, but I'll give you my opinion. My choice of colors has shifted slightly as I learn which colors work the best for me outdoors and in general. I have tried slight variations of this palette during each painting excursion, so it's never exactly the same. Color selection is not absolute and will change according to preference. You'll keep going back to the colors that seem to give you the best results.

My Palette in the field prior to wiping it down. 

Here is the selection I am currently using and I am pretty happy with the results I am getting at the moment. From the bottom left going up and around, the colors are as follows:

Titanium White; Cadmium Yellow Light; Cadmium Orange; Raw Sienna; Napthol Red; Quinacridone Red; Burnt Sienna; Viridian; Ultramarine Blue Deep; Cobalt Blue; Cerulean Blue.

I like to have a warm and a cool version of each color and sometimes a dark version as well. I also from time to time will use Alizarin Crimson, and Black, though I have increasingly gone away from Alizarin because I find it's tinting strength to be relatively weak. It tends to gray down pretty quickly and become muted with any mixture so it is very hard to get a clean purple with it. I use black if I feel the subject has a lot of strong darks that I need to mix, though I never use it straight from the tube. I always tint it with another color to shift the hue and liven it up. I got writing and found that there is more to this subject than I want to cram in today, so I'll do another post tomorrow to continue this.