This may be common knowledge for you experts, but not for me.

I'll just use two examples.

A white color car's undercoat is black.

A black color car's undercoat is white.

Why is that?

Why not switch it around so when a black car with black undercoat gets a scratch, it's ok, and not an eyesore.

 

Are you talking about primer?

If so: Manufacturers use the same primer (or e-coat) on ever panel to streamline the process. More material would be needed to paint cars a tinted primer and little to no potential gain comes from this realistically.

Different plants and manufacturers use different colored primers.

 

In the bodyshops they do it because if you're painting a white car with white sealer on it, you can't see where you've already painted. It ensures propose coverage. As far as facory goes it probably has something to do with the colors being more true. Whites usually cover really well and black's are thin and watery.

 

in my experience, no one ever paints a white car, with a black undercoat... the black undercoat might come from a manufacture's primer/ecoat... but if its black and it needs to be painted white... it will be sealed with a light grey or white sealer first. Black covers well, not white... as far as anything thin or watery... that usually comes down to how much reducer is added... unless you're using a cheap paint product... the paint grade i usually use are urethane based. they are not "watery"

 

I use and mix ppg deltron basecoat on a daily basis. Whites are thick and rich and pretty much cover any other toner up and blacks are watery from the get go. There's a reason Pearl whites are all tricoats. Because white covers.

 

yeah deltron is crap lol

but to each his own lol