After the grayscale preshading It was the critical stage to be made : the base painting.
The first layer was done with Lifecolor UA-259 (4BO ground shade) very diluted (in fact it was more colored thinner). several very light coats were made but I didn't very happy with the result because one base color did not made really the zenithal painting result I would like. (sorry I forget to take a picture of this stage). I have decided to add two others colors (4BO deep shade LC UA-260 and 4BO flashed shade LC UA-258) to add more intense zenithal effect.
Due to further processes, the effects will be a bit obvious otherwise with one single color I think it will be too subtle to see after all further weathering stages.
In my opinion, the grayscale (B/W) preshading will be done with only pure black and pure white. The several gray tones are too subtle to be see after the base painting.
All kinds of comments or discussions will be welcome.