Turning lace patterns upside down

This post isn't news to the knitting world, but since there seems to be quite a bit of confusion about it on forums when you google "knit lace pattern upside down" or somesuch, I thought it was worth a post.

Lets say (like me) you want to knit a seamless cardigan from the top down, but you want to include an all-over lace pattern.  Most lace charts are written bottom-up, at least in the stitch-dictionary on my shelf.  Maybe instead you are knitting a lace scarf and don't want to knit two shorter ones with a graft in the middle.  What to do?

Some A lot of posts on forums breezily suggest "just turn the chart upside down and replace decreases by increases!"  Don't listen to them, my friends.  While this may work for some lace patterns, it won't work for all.  And it may well look different from the lace knitted right-way-up, so I wouldn't try to match the two.

It is true you can expend a lot of brainpower and swatching time to devise an upside-down chart that retains most of the design features of the original pattern, but it might well not look the same in some key features.  There's a reason to graft your scarf in the middle!

Here comes an example:

This cute pattern of three holes is called "little flowers" in my stitch dictionary, or perhaps it's really little hearts.  Either way, it's cuter this way up than inverted ("little stack of bowling balls"?)  The chart is thusly:

Knitted bottom-up, you make the middle yarn-over (yo) on row 1, then the two yo on the next knit row 3.

Now turn the chart upside down.  You will make the two yo as your first pattern row - you can either make the decreases outside them, or switch to one centred double decrease in the middle.  By the issue comes when it's time to stack that last yo symmetrically on top of and between the lower pair.  There's a single stitch where we want our yo to go.  Where to put it?

The most obvious is to k2tog before the yo, or else yo then ssk.  Both these options lead to a "fat" bit between two of the holes, one side or the other, depending on which side you "got rid" of that central stitch to.  For clearer diagrams of this effect and how you can use it to make deliberate lace patterns, see here.

Here's my swatch:

Looking at the swatch above, the lowest motif is the original lace pattern worked from bottom up.  The next one up is the chart knitted upside down with a centred double decrease between the two yarn-overs.  Note that the pattern is no longer symmetrical - there's a fat bit between the bottom right hole and the central hole on top, due to the ssk before the last yo on row 3.

How do we get rid of the fat bit?  I tried two options.  The top motif in my swatch is the following chart:

I make one extra stitch on the purl row 2 by purling into the front and back of the central stitch, then I get rid of it again by doing symmetrical decreases around my top yo on row 3.  Symmetry is restored, but the pattern is less delicate - instead of a little yarn twist between the holes, there are fat bits on both sides where stitches have been knitted together leaning in both directions.

The second motif down is a bizarre non-standard variation on this theme, where the top hole is created by making the central stitch on the purl row very loose*, then on row 3 knitting into both sides and the top to pull it open.  I don't recommend it, and it looks much the same as my other symmetrical option which is easier to describe and execute.

* Insert needle into stitch to be knitted, yarn round needle twice, pull through stitch.  Like making a yo part way through the stitch.

The essential difference is that stitches are shifted by 1/2 stitch knitting top-down relative to bottom-up.  Think about the shift in the peaks vs troughs in a wave, or the number of fingers on your hand vs. gaps between them.  So, there's no easy way I can think of to exactly replicate the effect of knitting bottom-up while knitting top down.

In summary, I will be knitting my lace cardigan bottom-up with the original chart.