1940's Book illustration

As the time frame of the book Carries war will be around the 1940's I have decided to look into book illustration of that time. Lithograph was a very popular method of printing illustrations back in the 1940's. When first looking at the illustrations I have noticed that they all use very similar bright colours and a simple but still slightly realistic look. they also have very limited colour palettes and the same subdued, mainly primary colours are used a lot. Some illustrations from the 40's use an even more limited colour palette of one colour along with black and white, this will have been to save money as there were a lot of money shortages because of world war 2. 
I think the style of 1940's book illustration is very iconic and cannot really be confused with any other style. The look and feel of 40's illustration is coming back into fashion now but I still think it is possible to tell the difference between the original 40's books and the modern ones because the original style is so unique to that time period.
Here are a few examples of 1940's illustrations.