You can use free open source software to design patterns. Create an image with a width of 200 pixels or less with indexed colors. For two color knitwork, make the image monochromatic: black and white (1 bit) with each pixel representing a stitch. Save it in the PNG file format. The following instructions show how to achieve this using GIMP and how to benefit from the vector graphics program Inkscape to create scalable patterns.
Using GIMP to create patterns and save as PNG file
- Download GIMP 2.10.10 (or newer) from the GIMP homepage and install it.
- Run GIMP.
- In GIMP, left-click File -> New.
- Select the desired hight and width in pixels (= number of rows and stitches per row, respectively), then left-click "OK". See below to learn how to compensate for elongation of the resulting fabric.
- In GIMP, left-click Image -> Modus -> Indexed. In the dialog that pops up, select "black/white (1bit)" for textiles with two colors.
- Select the pencil tool (hotkey: N).
- Set the pencil tool settings to Size = 1.00 (1x1 pixel), Hardness = 100, keep other tool options at default settings (Dynamics Off). Keep default foreground color (black) and background color (white).
- Optionally show grid: Left-click View -> Show Grid. Then, left-click Image -> Configure Grid. Set Spacing:Horizontal = 1.00 pixels and Spacing:Vertical = 1.00 pixels. Left-click "OK".
- Draw the pattern (Zoom in using View -> Zoom to see individual pixels):
so that background color is represented by white pixels and contrast color (foreground) is represented by black pixels.
- In GIMP, left-click File -> "Export as". In the "Export Image" dialog that pops up, type in a file name and select the target directory, then left-click "Select File Type (By Extension)" -> "PNG (.PNG)", then left-click "Export". In the "Export as PNG" dialog that pops up, you can keep Compression level = 9 and optionally deselect all other options, then left-click "Export" at the bottom of that dialog.
- You can close GIMP now.
How to determine your gauge and compensate for elongation
If you want to create fabrics with exact dimensions and compensate for the fact that stitches are usually higher than wide, you should determine your gauge first: Choose your yarn and make a gauge swatch with it on your knitting machine (a small test fabric produced with the same settings as used for the final product). Determine the gauge (x = number of stitches per mm, y = number of rows per mm).
If the desired width (W) and hight (H) of the fabric or shape you want to create is given, calculate the required number of stitches (s) according to formula 1):
s = x * W ,
and calculate the required number of rows (r) according to the following formula 2):
r = y * H .
Otherwise, if the desired number of stitches per row (s) and the desired resulting aspect ratio [W:H] of the fabric or shape is given, use the following formula 3):
r = s * y / (x * [W:H]) .
Creating scalable patterns with Inkscape
To create patterns that can be scaled with optimal quality, design them in a vector graphics program. The following instructions use Inkscape which is open source. A video tutorial that also explains how to fill shapes with a repetitive pattern and how to adjust the pattern fill according to your gauge can be found in a post on the blog by DerAndere. Here are the basic steps:
Inkscape step by step
- Download Inkscape 0.92 (or newer) for free from the Inkscape homepage and install it.
- Run Inkscape, left-click "View" and activate the option "page grid".
- Left-click File -> Document properties. In the dialog that pops up, Set user-defined hight and width of the document in mm, so that the document is about twice as big as the desired size of the textile to be designed. Left-click the tab "grid" and set grid units to mm. Then set "spacing X" = 1 and "spacing Y" = 1. Close the dialog.
- Left-click on the tool "Create rectangle and squares" tool (hotkey: F4) in the left toolbar and draw.
- Choose the select tool (hotkey: F1). Select your rectangle and adjust it using the tool controls that appear in the toolbar at the top. The width and hight in mm of that rectangle should equal exactly the desired width (W) and hight (H) of the fabric part you want to produce.
- Left-click "Fill and Stroke" ([Shift]+[Ctrl]+[F]) -> Fill -> "Solid color". Set the value RGBA = ffffffff (white). Left-click the tab "Stroke color" and set it to "No color".
- Left-click on one of the drawing tools in the left toolbar and draw a shape of the desired size inside the existing (invisible) rectangle from step 4-6. For Bézier-curves, the drawing mode has to be selected from the toolbar at the top before drawing and double-click or pressing the [enter] key ends drawing.
- Choose the select tool (hotkey: F1). Select your second shape and adjust it using the tool controls or by dragging the handles of the shape with the mouse.
- Left-click Object -> "Fill and Stroke" ([Shift]+[Ctrl]+[F]) and set stroke color and/or fill color to "No color", RGBA = ffffffff (white) or RGBA = 000000ff (black).
- Left-click File -> "Save as..." and choose a destination and file name. It is recommended to indicate the part size in the file name.
- Determine the gauge (x = number of stitches per mm, y = number of rows per mm) as described above.
- Use the select-tool, select all objects including the background rectangle.
Left-click Object -> Transform..... Left-click the tab "Scale".
Change % to mm, verify that the option "proportional scaling" is disabled
and set Hight to the new hight h:
h = H * y / x .
Here, H is the desired fabric hight in mm. Left-click Apply.
- Calculate the required stitches per row (s) for your textile using formula 1): s = x * W . Here, x is again the number of stitches per mm, W is the desired fabric width (see step 5) in mm.
- Select all objects, including the invisible background-rectangle and
left-click File -> "Export as PNG" ([Shift]+[Ctrl]+[E]).
Left-click the tab "Selection" and set unit to px. Set
Image size:Width to the value of s (required stitches per row). Left-click "Export as", set the target path, type in a file name that indicates the part size and gauge and left-click "Export".
- It is recommended to undo step 12 by going to Edit -> Undo ([Ctrl]+[Z]) before making further adjustments to the design inside Inkscape.
- Optionally, open the exported PNG in GIMP 2.10 (or newer) and increase contrast by left-clicking Colors -> Levels and adjusting the Input min and max value (black triangle: set black point, white triangle: set white point). Left-click OK. Left-click Image -> Mode -> Indexed -> black/white (1bit). Then edit the pattern using the pencil tool and export as PNG as described in the previous section.
Using Inkscape to scale patterns for creation of differently sized textiles
If you have a pattern saved as SVG file and you want to change the resulting fabric size, you can scale it using Inkscape:
Scaling step by step
- Open the SVG file in Inkscape.
- If you want to scale the width of contours and Bézier-curves with the rest of the shapes, select those objects and left-click Path -> "Convert object to path".
- Select all objects, including the invisible background-rectangle.
- Left-click Object -> Transform... ([Shift]+[Ctrl]+[M]). If you want to keep the aspect ratio, activate the option "Scale proportionally". Set the scaling factor in percent (or change % to mm and set the desired Width (and Hight) in mm). Then left-click Apply.
- Continue with steps 12-16 of the previous section.