USDA/AMS is the most general source for visual color standards for fruits and vegetables and offers a catalogue of color comparators and equipment they have available.
USDA Equipment Catalog for Fresh and Processed Products Inspections is available on the internet USDA fruit and vegetable color standards document and provided through:
Processed Products Branch
Fruit and Vegetable Division, AMS
U.S. Department of Agriculture
P.O. Box 96456, Rm. 0709, So. Bldg.
Washington, D.C. 20090-6456
www.ams.usda.gov
USDA Visual Color Standards and other equipment related to fruits and vegetables can be ordered from:
Equipment & Forms Depot
USDA, AMS, FVP, SCI
831 Mitten Road, Room 200
Burlingame, CA 94010 USA
+650-552-9073
FVSupplyDepot@ams.usda.gov