The TC1617 is a collection of CMYK patches commonly used in profiling CMYK devices like printing presses. It contains a good sampling of the entire printable gamut, as well as the neutrals that are commonly used to calculate gray balance using the G7 method.
TC1617 is a common name for this target. The proper name for this chart is IT8.7/5.
This patch collection was created by removing the duplicate patches from the 1617-patch IT8.7/4 target, and replacing them with the K-only patches and the CMY-gray patches of the P2P51 target, resulting in a chart size that remained at 1617 patches.
While the IT8.7/4 chart was very popular in the industry as a profiling target, it lacked a good sampling of neutrals. The TC1617 resolves this issue and is highly recommended as a good CMYK profiling option in a compact size.