Double Jacquard and color separations: some previous posts, links, hints

A recent forum discussion on DBJ on Ravelry led to my looking back on some of my previous posts. Some of the features in both excel and numbers changed over the years, but most basics remain. Program specific or a “software” general search in previous posts touch on GIMP, other programs and other fabric design choices.

Color separations:
http://alessandrina.com/wp-content/uploads/2013/04/DBJtest.pdf
http://alessandrina.com/wp-content/uploads/2013/04/CCI08012016_2.pdf
http://alessandrina.com/2013/05/14/vertical-striper-backing-on-brother-km/
http://alessandrina.com/2015/04/18/a-simple-shape-an-exercise-in-dbj-brother-km/
http://alessandrina.com/2013/04/22/double-jacquard-2/
http://alessandrina.com/2013/11/01/color-separations-for-knits_-mac-numbers3-some-excel/
http://alessandrina.com/2013/05/04/double-jacquard-3-single-bed-multi-color-slip/
http://alessandrina.com/2013/06/19/double-jacquard-separations-4_-making-them-work/

Added points on separations: the post addressing how to color separate for use on punchcard machines helps illustrate the how tos involved in hand separations

Tubular Fair Isle 

Color changer:
http://alessandrina.com/2014/01/26/some-notes-on-machine-knitting-color-changers/

Ribber backing settings for DBJ http://alessandrina.com/2017/11/09/a-return-to-brother-ribber-and-dbj-settings/

Ladder back ribber settings illustrated (no actual pattern knitting involved), http://alessandrina.com/2018/02/09/ladder-back-double-jacquard-backing-variations/

Most color changers only accommodate 4 colors, so in creating separations for double jacquard, this tends to be the maximum number. The more colors one uses in a row of knitting , the more all the stitches on the face of the fabric must stretch in order to accommodate the colors laid behind in the backing fabric. The more the stitches on the front face of the fabric must stretch, the muddier the look of the design, and the more “bleed” or “grin” through  of the backing colors through the stretched stitches. 
A color separation is required. The best method for the separation depends on the knitting technique to be used , the knitting machine one owns and its capabilities, the desired look of the finished fabric, and the method for creating the separation. 
Method 1 (graph 1): always works. Knitting occurs for one design row at a time. The knit design row 1 is expanded into 8 on a graph = row 1 color 1, row 2 color 2, row 3 color 3, row 4 color 4. In order to knit the design, this separation would need to be elongated X 2 in order to make passes to and from the color changer . The result is likely to produce elongation in the image, regardless of backing method used. In Japanese machines one usually performs the first preselection row toward the color changer. Passap is a bit different. In addition to the 4 color changer being on its right, the first pass to the left aligns pushers and needles, the second pass to the right preselects pushers for the first row to be knit after the color change on the right. The  original design may have an even or odd number of rows, since each row will be knit twice
In Method 2 (graph 2): the first preselection row is performed moving away from the color changer, so that the ground color is knit first for one row, moving toward it. This should fill in the majority of the needles. When the last row is reached, the color is changed back to the ground color, Row 2, the carriage will be on the right, heading back to the color changer as the sequence is completed. The expectation is that the ground color, 1, will knit the majority of the needles. 
Method 3 (graph 3): is similar to Method 2, but the ground and background are not split in the first 2 rows of the graph. This is the hardest to achieve in terms of knitting without errors in patterning or dropped stitches. The main color knits for 2 rows before the other colors knit, may alter availability of needles required empty for placement of the stitches in next color row. 
In both methods 2 and 3 the design must have an even number of rows.
Method 4 is based on color layer separations. Machines such as the E 6000 allow the knitter to superimpose designs (rules for order may vary), and offers techniques for then performing the separation for the knitter, usually as seen in Method 1. The size of the motif for automatic color separation is dependent on available Ram and the knitting machine model. This is a copy of one of one of my handouts when teaching DBJ eons agoAnother former handout, intended for Passap knitters. Many of these fabric options could be emulated on the Brother machine, if separation method 1 were available, with a bit of interpretation. A machine knitting cross reference chart