ORIGINAL: da Rock
When Monokote first came out there were a number of magazine articles that mentioned covering weight. (back when magazine articles were more than advertising copy for ARFs)
The writers were usually just modelers who had discovered that the new stuff looked lighter, and seemed like it had to be lighter than a full paint job, but had discovered their newly finished scratch/kit built airplane covered in the magic stuff wasn't lighter at all. Or not significantly lighter. So they did what real modelers do and did some simple tests. And reported what they'd done in their next construction article.
And the comparisons were eye opening for most. Because it really seems to most everyone that the plastic films HAVE TO BE lighter than paper or silk and dope.
So I wish his chart had given a bit more test results on the two lines that cover silk. Because silk and silkspan can easily be done such that you've got a decent finish, and the outcome is lighter than Monokote/Ultracote/etc.
The above is true. However, there is a cost associated with paint. In the case of some competition u-control models, I've heard numbers in the $125 to $150 for the materials! Their finishes are really super and usually very light!
Paul