Index separations can achieve amazing results, but the best examples of this process use upwards of 10 colours. This is not cost effective on smaller T-shirt screen printing orders, as screen, artwork and set up costs on say a 14 colour screenprint would make it impractical to print less than 1000 off. The Index method is also known for improving through the duration of a print run, this is a result of the ink deposits being side by side. With no overlapping/overlaying of inks there are less of the associated problems on press, where CMYK is often very problematic. It is these reasons which pigeon hole this technique for large orders only, as many screen printers opt for simulated process on smaller presses.

However, on the odd occasion it can produce great results using only 4 colours, as per photo. These index separations can be created in photoshop quite easily without any additional plugins.