I used to have a client with a product that had deep, low-reflective black shelves and brushed chrome uprights. The customer wanted these on a white background for catalog use.

Using a 1600 watt-second four light set-up shooting through 4' x 8' diffusion panels and a Minolta IV flashmeter in incident mode, I created a nightmare in the darkroom as I blasted the reflected light off of the brushed chrome blocking up the brushed chrome look or, alternatively dumped the white background into blotchy shadow that required tough up to print pure white.

I solved this problem by going to a light-yellow seamless paper, using the 5 degree spotmeter attachment and metering off of the deepest blacks and adjusting development to hit the right level for the chrome. I then shot these using a #12 yellow filter (1.3 stop adjustment) which cleaned up the background. The negatives were an absolute dream to print!

For me, this is the difference between incident light meters and reflective. An incident light meter will give you the "correct" exposure provided your subject is of "normal" contrast. Reflective light meters will tell you about your subject so you can chose an appropriate exposure and adjust your development (in the case of color transparencies) add or subtract light to hit the sweet-spot for contrast.