How can 30LPI be the same thing as 300DPI?

If the full image resolution is 300DPI, then doesn’t that mean each inch of the design is composed of 300 “dots” and isn’t a “line” merely a line of “dots”, and wouldn’t that mean a halftone has a max resolution of at least 150 LPI ('cuz to render halftone “dots”, you need at least two lines of dots, one present and one missing)?

I don’t get the 30 LPI stipulation. Are the number of halftone “dots” per inch really limited to 30? Does it have something to do with being able to render the halftone dots at different angles (like 45 degrees, instead of 90 degrees)?

Hello Reverseemf, I found this site that helped me understand halftones and lpi a little better.

http://t-biznetwork.com/computergraphics/all-about-dpi-lpi-ppi-more/

We also have a nice blog post from 7 years ago that came in real handy for myself.

https://shirt.woot.com/blog/post/design-tips-i-have-become-halftone-destroyer-of-shirts-part-one

Awesome, Thanks!

So, what I’m gathering from reading these splendid documents is: the 30 LPI stipulation is for the Largest Dot Size in a Halftone, right? The Largest Dot is for the “Darkest” non-solid tone of that particular color. As the tone gets lighter (or more transparent), the dots get smaller, and, in fact, the printing resolution (ie. 300DPI) sets the lower limit on dot size for a Halftone. BUT, even when the dots are smaller, they are still spaced at 30 LPI (i.e. the spacing between dots doesn’t change). Or, actually, as I think of it, 30 LPI IS the spacing between dots, right? And, BTW, the dots are rendered at the printing resolution of 300 DPI, no…yes…maybe?!?

Does it sound like I’m getting the idea?

It sounds to me that you are getting the idea. I myself am pretty new to using halftones. I can tell you, with out printing, 30LPI in about the highest number that prints consistently.