Since I saw there were a few people asking about this i thought i would explain.
the number is the difference in rank between the produced item and the lowest rank of any of the components.
for instance, if you compound a rank 6 and a rank 8 item to product a rank 10 item...this would be +4 (hence 10 - 6) since the result gained 4 ranks up.
for primary alchemy, +4 is the most ranks a compound can gain without alchemy books, thus making it the hardest to produce. compounds with lower or negative numbers are more common than items with +3/+4 or higher.
Last edited Fri, 19 Dec 2008, 9:54pm by scott