Geometric shapes on ribber fabrics with tuck stitches

The previous post elicited a facebook query as to whether it might be possible to create solid shapes within the field of brioche vertical stripes. The inspiration for the query was a hand knit pattern published in ravelry 

https://www.ravelry.com/patterns/library/pariss-brioche-scarf 

Many terms are used in instruction manuals and published directions. In my notes I will refer to fabric with tucking on both beds as  full fisherman rib, tucking on one bed only as half fisherman.  These were my first attempts at exploring the inspiration idea, the fabric has inherent differences as it requires both slip and tuck stitch settings, so technically it is neither fisherman. Knitting happened on a random drop stitch day, which explains the patterning interruption errors. When attempting to knit isolated geometric areas on a field of frequently tucking stitches, automating the task when possible makes the process easier and faster. This was my first “diamond” pattern repeat, suitable for a punchcard machine as well. The design is illustrated on the left, converted to punched holes/black squares/pixels on the rightThe knit carriage is set to tuck throughout. The programmed repeat will alternate the knit/ tuck functions across the bed based on black squares, punched holes, or pixels. For full fisherman rib (top swatch) the ribber needs to tuck in one direction only, opposite to the action taking place on the main bed. A choice needs to be made on either of these 2 setting directions based on needle selection on the main bed, and stays fixed throughout knitting.  The ribber is set to knit on even numbered design rows on the card, to tuck on odd. Row count numbers may be different than design row ones depending on row counter settings by the operator or built KM ones. Below are tuck settings for to the right on top, to the left on the bottom.

For half fisherman rib (middle swatch), the ribber is set to knit with every pass.

Note the half fisherman fabric is narrower than the full. Also, I am not used to my 930, overlooked that the machine was set for isolation, so its bottom diamond shaped repeats are incomplete. 

In the bottom swatch I tried to produce a more distinct shape on tubular tuck created with only knit stitches on both sides of the fabric. Hand selection on the alternate beds on all tuck rows produced knit stitches in the desired area. A needle out of work made it easy for me to find proper location on needle bed .

Getting back to automating at least part of the process for such shapes: the repeat needs to be alteredThe main bed will be knitting the black squares in the chart on the right on every row, tucking the white ones. When the ribber carriage is on the side appropriate for it to tuck the following row and no needles are selected in design segments on the top bed (odd numbered design rows, ones with majority of black squares, tuck <— —>  may not be used in those locations because then the resulting stitches would be tucking on both beds with nothing holding the tuck loops down. 

bring all needles between selected main bed needles up to hold on the ribber so that they will knit while the remaining needles tuck on the next pass of the carriages. 

In my sampling the ribber was set to tuck when moving from right to left. Below is the resulting swatch, shown on both sides. Part of one diamond shape is missing due to the fact I was concentrating on moving needles around and missed the change in selection on one side of the machine.Back to the original the method used in the previous post where ribber settings are changed from knit to tuck <– –> every 2 rows along with color changes. I chose a design that would  make it easy to identify location of non selected needles on the main bed on rows where ribber will be set to tuck in both directions. The result is interesting, but the “solid” areas, narrower than the remaining knit, are in the opposite color to the dominant one on each side, the reverse of the inspiration fabric.
When needles are not selected on the main bed, interrupting the every needle selection bring all needles on the ribber between selected needles up to hold on each of the 2 passes from left to right, and right to left. Stitches on those needles will knit rather than tuckresulting in this fabric The first swatch at the top of this post was achieved going a very different route. Two knit carriages were used to select and knit from opposite sides of the machine. Each carried one of the two colors. When working with the first color and  coupled carriages  the main bed is  set to tuck <– –>, and the ribber to knit <– –>. The second color is knit using the main bed knit carriage only, set to slip <– –>.  A knit sinker plate may be altered  and  used on knit on main bed only rows, adjustments to it are shown in post http://alessandrina.com/2018/04/15/ribber-fabrics-produced-with-2-knit-carriages-selecting-needles/. The chart for my working repeat with a multiple of 4 rows in each pattern segment, color changes every 2 rows indicated on rightIn trying to produce a diamond shape using this technique, my first repeat had arbitrarily placed pixels: the cam settings on the right of the swatch images correspond to those used in each swatch segment. Colors were changed every 2 rows throughout. First 2 rows in pattern were knit in tuck setting, followed by 2 rows knit in slip. In segment B when no needles were selected on the top bed, all those needles were brought out to hold before knitting to the opposite side. Because every row is now knitting in corresponding color changes the result is a striped pattern. Segment C is knit with both carriages set for 2 rows as in C1 alternating with knit carriage only set as in C2.  At that point the color being carried knits only on the ribber, skipping non selected needles on the top bed, avoiding the striped result. A float is created between the beds in areas where no needles are selected that will be “hidden” as one returns to knitting in rib with 2 carriages.  The arrow in the chart points to an area where two colors were picked up with the color swap rather than one. The resulting swatch samples 

Analyzing the result in section C: the diamond is the same color on both sides, whereas the initial rectangular shape experiment reverses the colors. Reworking the diamond repeat in segments that are each a multiple of 4 rows:Other considerations in DIY designs. The background repeat for this pattern is actually composed of units 2 wide by 4 rows high. If the pattern is intended to be repeated across a larger number of stitches on the machine bed than that in the chart, it is always worth tiling the image to pick up any errors (sometimes happy design features).  Tiling in width readily shows the error, tiling in height as well proofs row intersections as welltiling the corrected width repeat, now 42 stitches wide by 72 rows highI sometimes tend not to keep immediate notes when I test ideas, which often comes with a price. I knit my first swatch using this repeat beginning the pattern with 2 rows of tuck, resulting in this fabric (and some randomly dropped stitches once more) with the same color diamond on both sides:Beginning the pattern with 2 rows of slip stitch on the main bed only mirrors the swatch at the start of this post. Where no needles are selected on the main bed, with passes of the combined carriages, two rows of tuck will now be produced, resulting in the wider geometric shapes and the increased bleed throughThe tuck loops created by the white in this instance have the elongated slip stitches in the alternate color (blue) partially covering them, creating the darker geometric shape in the top detail photo. The blue is thinner than the white, the effect will vary depending on yarn weight and tension used for the main bed yarn. One can begin to observe the change in width in areas with more stitches tucking. 

If the aim is to have a tighter, more clearly defined diamond, after the swatches rested, the swatch that began in slip stitch setting appeared to “work” better to my eye, even with the single color geometric shape on both sides taken into account. Ultimately the choice is a personal one.  The wider vertical stripes created in the white yarn in the slip combination fabric happen because of the 2 stitch wide repeat on the top bed as opposed to a single needle one in a true fisherman knit. Because of the slip setting the results will be narrower in width from it as well.

Ayab knitters will need to program any repeat across the width of the intended number of stitches, and use the single setting. Electronic knitters can enlarge the background pattern field easily, or create brickwork, extended repeats.

Arah-paint offers a free program that allows drawing repeats in different orientations with a few mouse clicks. Shifting the this pattern must also be in pairs of pixels/black squares in this instance because of the 2X4 stitch background unit. The 21 (half) pixel shift shows an error in its continuity a 22 stitch shift results in a “correct” all over repeat