"Flat field" usually means "relatively flat within a certain range of magnification," and enlarging lenses are designed to fit that description for typical use (or sometimes special use in the case of lenses like the Rodagon G lenses for mural sized enlargements).
I guess we're hijacking the thread so I apologize but I also now have a question concerning glass carriers.
In my previous experience with Leitz enlargers , the negative carriers were open at the bottom with an ANR glass ring at the top and they held the negatives very flat. The universal LPL carrier (for 35mm thru 6x7) I just bought has glass on both the top and bottom. I'm wondering if the bottom piece of glass is necessary?
I guess we're hijacking the thread so I apologize but I also now have a question concerning glass carriers.
In my previous experience with Leitz enlargers , the negative carriers were open at the bottom with an ANR glass ring at the top and they held the negatives very flat. The universal LPL carrier (for 35mm thru 6x7) I just bought has glass on both the top and bottom. I'm wondering if the bottom piece of glass is necessary?
The glass negative carrier for Saunders LPL enlarger needs both pieces of glass to function properly. The maksing blades provide not support for the negative.
I presumed that while the top, AN glass was important for preventing Newton rings, the bottom glass (for sheet film) was important because for sheet film, sag is the problem, not curl. Is this correct?