Hi all, I've been looking a photographs of various tartans, and one thing stands out...unnatural color casts, due to the available light. There are several things you can do to get a more natural appearance.

Use your fill flash, or manual flash setting indoors, even though the overall lighting is sufficient, or the subject is in deep shade outdoors. Your camera (I assume most are using digital these days), should automatically render the correct amount of light.

Your flash will render a daylight exposure.

Or set the white balance for whatever light source you are using, daylight, outdoor shade, fluorescent, or incandescent lighting.

The best outdoor lighting is high, light overcast, with few shadows.