Prints and Printing

[noreturnphotos]

I decided to enter some of my stuff in the local county fair here where I live. Mostly because I wanted to get some "exposure " for the co-op gallery I joined, and to see how I would do in compairasion with the other artists in the valley.
I had a couple of photos I know would have done better if my prints would have been their best. I say this now because of a book I am reading on the subject. I see now that the print I am refering to didn't print the same as other times I have printed them out in a smaller format (8x12). I also have noticed that when producing in larger formats, the photos take on even different characteristics.
So my question to everyone in the know....
How many of you use working prints to make your final adjustments, do you use working prints, thoughts on the process?
royce