A quick example of making the Material that Sam had created on Photoshop. This is not the painting used as a material but, simple colour so, Sam could break down the scene and see how the layering would look like on Ue4

Please refer to his blog for more in depth explanation.

Sam’s Blog: https://samsgamesdesign.wordpress.com/blog/?fbclid=IwAR07QoCC7QOc5kZMN3Ayba-JNSGsE6_M7SYiPrxgP9aB0Jpdk4ByCIFtbug