We provide some illustrations below on photographing art pieces. All the photographs you see here was color corrected with the white/grey/black strips. X-Rite/Pantone color chart is included for reference.
Here I am using a lightbox with 5000K (as advertised, but actually it is about 5300K) LED lights. The art is a piece of quilted fabric, measuring 17" square.
Here I show how to place the grey strip and/or the color chart to include in submitted photos. The color strip I made isn't perfect, but it is close enough for this purpose, and I know what the color bias is on each patch to make appropriate adjustments in Lightroom.
This is the actual digital capture that will eventually make it onto print. This was photographed from directly above the art (light box has a top opening also).
Cropped with enough margin to add matting on top. This is the actual print file. I scaled it down to print 8"x8".
This is the digital reproduction, printed onto a photo rag matte paper, matted and framed. The frame opening is 12"x12".