Reddit post:
https://www.reddit.com/r/magicTCG/comments/6tbiv7/differences_between_4th_and_5th_edition_using/
Here is 5th Edition.
As the quality of counterfeits increase, it will become more and more important for collectors of early Magic cards to understand the details of what the genuine cards look like. This is a brief exercise in training the eye to memorize the rosette patterns. It is important to understand the variability that exists in the genuine cards printed. All of these cards were printed with four color plates, and using the exact same printing method: CMYK. That means that for each sheet, there are four separate color plates: Cyan-or Blue, Magenta-or Red, Yellow, and Key-Black.
Here is a link to the Wikipedia article on CMYK printing:
https://en.wikipedia.org/wiki/CMYK_color_model
I think knowledge about the genuine cards can be collected from all of the early cards, including the reprint core sets.
The frame makes the artwork seem larger in the 4th Edition printing.
The frame makes the artwork seem smaller in the 5th Edition printing.
Here they are side-by-side.
I don't see much of a difference in the artwork in the way of retouches or color variation besides the obvious darker print for 5th Edition when compared to 4th Edition.
The text frame in 4th Edition...
...is somewhat different. The font is slightly smaller for 5th Edition, and the flavor text is spaced out downwards.
Even though every other feature is wider in 4th Edition, the text box is smaller than the 5th Edition text box.
The background of the text box is darker in 4th Edition.
Here is the top of both cards. Notice that these two cards are completely different from the ground up even if they have the same text and artwork. Look at the placement of the title and the size of the casting cost number. Notice that the 4th Edition card is slightly wider.
Same with the bottom. The 4th Edition card has an additional dark line drawn along the bottom edge.
Here are the rosettes from the bottom and to the right of the text (top is 4th Edition).
Here are the left edges turned sideways, with 4th Edition now on the top. Notice how much taller the 4th Edition card is.
Here are rosettes from the left edge. Right is 4th Edition.
Here is the right edge turned sideways, with 4th Edition on the top.
Here are the rosettes from the right edge. 4th Edition is on the right.