Not in Finnish today, sorry!
You can find lots of very valuable hints of continuing the yarn and working the ends as you go in the TECHknitting-blog. I started discussing about a method of thinning the back join, but the answer grew and grew and I might include some pictures afterwards so I ended here. Sounds almost like I'm excusing for blogging again (I'm not! :)
I'm a big fan of the back join to continue yarn, not matter whether the color is changing or not. Mostly the extra bulk does not matter, but sometimes I want to avoid any bulk at all. Like: I happened to be in the middle of the front of a sweater I knitted for G a while a go as the yarn just, well, ended there, with no warning! OK, so I was not paying attention, and I would have preferred to continue the yarn on the side of the sweater, but didn't want to rip half a row either... call me lazy. It worked pretty well.
You can "thin out" the back join or the overlap join to avoid bulk by splicing a multi-plied yarn,
i.e., cutting off 2 plies of a (say) 4-ply yarn for the last 3-4 inches (I use usually some 4-5 sts length) and keeping the other 2 plies.
Then make a (say) back join with the remaining 3-4 inches of half-the-yarn.
Allow little overlap between the cut (short) end and the long end, depending whether you want to sew in the ends afterwards.
Knit a couple of stitches, depending on the size of your loop, to make joining the new end easier.
Do the same with the new yarn end, cutting half of the plies (in this case 1 of 3 in a 3-ply yarn)
and making a loop of the remaining ones.
You will have no bulk whatsoever in your join, but the yarn will always have the original thickness.
The problem with this method is that there is a change of getting wisps of the remaining threads sticking out of the fabric, also in the right side.
I'm discussing two cases of avoiding these wisps, unfortunately both of them are imperfect:
*If I'm lazy and the back side is not going to show, I separate the short and long end for an extra inch, do not overlap the ends but only make the loop on the long end (back join) allowing also the long end some 1 inch extra at the point in which the short and long end are separated. Now I have 1 inch (or as long as you wish) of both long and short ends coming of the fabric at the same spot. After the blocking I can handle them like I would for a normal back join except that the threads of the yarn are separated. Usually I just cut the ends leaving some 1/4-1/2 inch extra on the back side (like the inside of a sock).
*If the back side is going to show,
1) I separate the long and short ends for at least ca 1 inch.
2) I make a loop of the long end and overlap the long end with the "whole" yarn at the point where the short and long end are separated, leaving at least 1 inch extra for the short end to be weaved in later, as well as 1 inch of the long end beyond the overlapped part.
3) If possible, I spit-felt the long end together with the "whole" yarn for the first sts that I'm using to knit i.e., the point where the back join starts (however adding bulk again, but not as much as in a normal back join).
4) As previously, I leave the ends to be cut after blocking. However, this leaves you with the doubled amount of ends, since the short and long ends are not coming out of the fabric at the same spot. That, is in my book, means a doubled probability of wisps.. so it might be necessary weave the spliced ends, or maybe use the overcast-method.
Now this is G's sweater, showing two wisps where I joined the yarn.
In the case of the G's sweater the yarn, despite of being merino, was not felting but rather cotton-y, so I left pretty long ends hanging in the join (maybe 3 inches each) and after "back join with 1 sts overlap of the whole yarn and the long end" did something similar to the overcast-method to weave in the thinned-out ends as I went (for a couple of stitches per end and row), and also weaved in the remaining ends after blocking.
The wisps were not visible first, but after some weeks use they popped up in the front. Since the inside of the sweater is not showing I just thucked them in
- problem solved! I the picture of the purl side you can slightly see that some ends have been woven in, but this does not show in the knit side.
I don't think the ends are going to pop up in the front again, but even if, I'm just going to keep thucking them in, I think.