OK, Don says USPCC don't print the proof and the print run in the same way. Fair enough. I am sure he knows better than I do how things are in their factory. But that rather defeats much of the point of the proof to my mind.
Creating a printing plate is a bit of an expense - it's why USPC doesn't use the same process for making proofs. They print proofs on a digital printer so you can have some idea as to what the project will look like - it's not 100% identical, but it's pretty close in terms of color and it's exact in terms of the line work, placement of objects, etc. So you might not see the precise shade of yellow you wanted on the clothes of the Queen of Hearts, but you will see if the Queen of Hearts has an index, one eye or two, the proper number of fingers on her hand, etc.
Thanks for your replies. Good to know a prototype is printed differently. If the Kickstarter goes through I guess I'll be a nervous Nelly until the final product shows up. I'll be using MPC to start and hopefully there is some give in the deck I'm creating. It is a marked deck using different shades of colors and some tricky optical illusions that are essentially invisible to the naked eye.... The colors being printed differently than designed might be the difference between the deck no longer being marked or even worse being obviously marked and unusable. Card faces aren't sensitive but the backs will all have slight color variances to identify the card.
I agree that printing the final run and proof differently kinda defeats the purpose. For the artwork it makes sense but I guess nobody imagined a project that would be so color sensitive.
If you use MPC, the "proof" is simply a one-deck print run (or more than one, if you choose). You can get it as an uncut sheet or as a cut deck, your choice. They're not perfect in their print work, but they've improved a lot and they're a good choice for a budget project. I saw one project that had a lot of sharp lines and right angles in monochrome scheme - the prototype didn't come out all that good for it because of the digital printing process; you could see print lines from where the ink heads made their passes over the sheet. But it was the nature of the project - a different design, something with more colors and perhaps some curves or something, might have better hid the rough edges that showed on this project. No matter how you slice it, MPC will give you the best shot of success because you can print the tiniest of print runs - higher per-deck costs, but much tinier budget overall, allowing you to get the project off the ground with just a handful of backers and careful budgeting.