A custom printed watercolor paint tin box is different from a conventional school pencil case. The metal case may need to organise solid pigment pans, pencils, short brushes and other art tools while also providing a practical opening layout for painting, travel and retail presentation. For art-supply brands, the important question is therefore not simply how large the tin should be. The internal depth, pigment-pan arrangement, palette area, pencil clearance and method of keeping each component in position all influence the usability of the finished product.