Smile or no smile?

According to the Standardized Textbook of Barbering, a properly honed razaor should have a slight smile -- the blade's cutting edge should curve up slightly from the center toward the point and the heel. However, most honemeisters hone their cutting edges to be straigiht across, parallell to the spine. So why the discrepancy?

Straight is alright but I like a slight smile. I can't speak for why some design their blades to be perfectly straight. I shave with both types and they work well. The important thing, as the barber manual says, is to avoid a frown.

I think the short answer is time.

A honemeister might hone a particular razor once or twice. To put a smile on a straight blade, by that I mean a blade that was made without a smile by the factory, requires quite a few honing sessions using slightly heaver pressure at the beginning and end of the stroke to transform the straight blade to one with a smile.

I can't speak for others, but, in general, when I hone, I try to put the least amount of wear on the razor as possible, so I try to maintain the edge in whatever shape it is in. This is because I want to get good shaves, but I also want to preserve my razors.

I don't know, but I'd assume the barber books are from a time when more straights were still in production and they were cheaper/easier to get. If I could get say 10 of the same razor for not too much, they were tools for my trade, and all that mattered was giving the customer the best shave, I would have no problem honing a smile into whatever razor I was using for customers to do my job better.

I think the barber books have to be read with context in mind, and that is my understanding (thought it may be wrong) of the context. Also, I'm not familiar with the book you're referring to, but I'm assuming it's old and all my other assumptions follow from that.

I read that some barbers would mute the point on their razor as a precaution for customers. Could a smile be a similar issue, not necessarily for safety but to give better shaves or make shaving different faces easier?