If the lighting is poor and it is a critical color decision, collect a sample and look at it the next day under natural light. Get another personís opinion. Do not close the sample in an airtight bag, as color may change. In some soils (i.e., reduced matrix), colors may change upon exposure to air.
Moist soil colors are critical. All hydric indicators and color guidelines refer to moist colors. If the soil is dry use a squirt bottle to moisten it.