Why centimeters and not inch?
Judging by comments from beginners coming to the shop, inch is scary. Especially if the newbie is going to learn on their own, i.e. not living somewhere they can easily sign up for a class where they immediately are presented to inch measurements. The magazine class is first and foremost directed to the quilters who can’t attend an actual class, and Trine hopes those who don’t have personal support can be inspired and learn from the magazine pattern (I'm still not convinced it is good to teach centimeters to beginners knowing the bulk of patterns out there are in inch, but that is the reason for their decision).
Trine had drafted the blocks full size so those wishing to could measure for themselves and chose whether to use cm or inch, unfortunately the magazine opted against printing the blocks full figure. She says it is sometimes frustrating the editors making changes and cutting back on illustrations and explanations, but she is still confident beginner quilters will learn what they need to make the quilt from what the magazine has printed.
Block size and weird fractions
The original BOM from the shop had 9” blocks, the blocks in the magazine finish at 20 centimeters (just shy of 8"), so the patterns are not interchangeable. The blocks are constructed over grids of 2,4,5 and 7 units so no matter what there would be some weird fractions in some blocks, the change in size was to make the fractions less weird. So those who started out doing the first blocks in 9” size has to bare in mind that changing to centimeters for the more complex blocks will end up with two different sizes.
Why a whole centimeter seam allowance?
1 cm is marked on the needle plate on most sewing machines and easy to line up fabric to. I took another look at my Bernina – it has markings every 0.5 cm, but it also has 1/4” inch markings, so… And let me tell you, I'm not giving up my quarter inch presser foot for anything! I looove that little gadget!