Knitting a Picture – Photos to Color Charts Part 2

Where We Are –

The first tutorial covered some basics:  tool locations, opening an image, basic formatting, and how to get your chart onto paper.  This time we are going to go a little further and actually alter the image before we place a grid over the top and convert it to a chart.

A quick glance at the photo on the left shows some very subtle color gradation – each color gently blurring into the next.  While it makes a great looking picture, the problem with knitting it is that yarn doesn’t blur.  Yarn is a very definite size, shape, and color, and doesn’t mix colors easily.

Those familiar with Bauhaus knitting will know the solution to shading colors with yarn lies in many tiny stitches and many different colors of yarn.  If you are knitting with eight different colors of blue, and you knit with the colors in the order of darkest to lightest, then you will get a pretty good resemblance of those colors fading into each other.

When applying this to an image not originally intended for knitting, we need to know how many colors  we are dealing with, which is where GIMP comes in handy.

You Will Need the Following:

  • A high quality digital photo copy of the image you want to chart (don’t use the original in case something happens and the original is accidentally erased or permanently altered), preferably one that is very simple with two colors, similar to my example.  For two color images click here.  For photos with complicated shading, try here or here.
  • GIMP photo editing software – in theory another photo editor will work as well, but the instructions below are GIMP specific.  For those of you who don’t have GIMP, it is free photo editing software, Mac and Windows compatible, and very, very powerful (read tricky to use).  For those of you who are already thoroughly familiar with Gimp’s capabilities and are confident about what they are doing, I applaud you.
  • The ability to take a screen shot of just part of your computer screen (I use the Preview.app on my Mac)
  • A printer
  • Foreknowledge of the size chart you want, the gauge in which you will be knitting, and the number of different colored yarns you intend to use.  Note: if you use a small gauge with a large chart size, the resulting knit design will turn out better than if you use a large gauge with a small chart size.  The more different colors you decide to use, the more accurate the image will turn out.  

Some Introductory Explanation:

This is a high contrast image with only two main colors (blue and white), but several different shades of those colors.  To make this image into a color chart, I need to eliminate some of the shading and convert the ambiguous colors into one or more definable colors for knitting.

The more shades I eliminate, the more the design will change in appearance from this image to the final knitted object.  So why eliminate anything?  Because otherwise I would need to have a color of yarn to match every single shade, hue, and tone in the image – possibly dozens of different strands carried.  This makes for a messy back, lots of knotted yarn, and a memory teaser figuring out which blue is which.

Or I can just limit the number of blues.

The Instructions –

1. Read ALL of these instructions first.  Do not attempt to work along with the instructions.  Some prep work is mentioned in the middle because that is where it contextually made sense to put it.

2.  Open the GIMP program on your computer.  To download GIMP, and for help using it visit this site

3. Click File > Open Image and select the image you want to convert to a knitting chart.  The image should pop up in the editing window.

4. At the bottom of the image window next to the zoom display is a tab showing what measurement system the window is using to show the size of the image.  Change the tab to show inches.

5. Change the zoom to read 100%

6.  In the header bar, click Image > Scale Image and a new window should open

7. In the Scale Image window, change the width to the number of inches desired, and hit enter.  The height should change automatically.  Click the Scale button in the lower left corner to alter the image.  Make sure that the resulting size of the chart matches the desired size by looking at the editing window and making sure the edges of the image line up with the desired inch measurement.  Note:  If you are having trouble viewing the whole image now, in the header bar click View > Zoom > Fit Image in Window, and you should be able to see the whole image once again

 8. In the top header bar, click Image > Mode > Indexed and a new window should open.  Under the Colormap heading make sure that “Generate Optimum Palette” is selected.  In the “Maximum Number of Colors” field, enter the number of different colored yarns you have chosen to use.  For the example image, I chose four blues and one white for a total of five different yarns.  When you have entered the number, click the Convert butting in the lower left hand corner.  Your image should change pretty radically, flattening out the shaded colors into one tone.

9.  In the top header bar, click View > Show Grid and a grid should appear on top of your image.

10.  In the top header bar, click Image > Configure Grid and a new window will open.  Under “Appearance”, change the foreground color to black and the line style to solid.

11.  In the Configure Grid window under “Spacing”, you will need to enter numbers which reflect the gauge of your knitting project.  Most projects give the gauge in four-inch increments, for example: 17 stitches = 4″; 22 rows = 4″.  To convert our example measurement for use in GIMP, we need to dust off some third grade fractions.

First, divide the number of stitches by the gauge swatch measurement, and the number of rows by the gauge swatch measurement.  Using our example measurements:

17 sts ÷ 4 inches = 4.25 sts per inch

22 rows ÷ 4 inches = 5.5 rows per inch

Second, divide one by the new stitch number, and one by the new rows numbers.

1 inch ÷ 4.25 sts = 1 stitch 0.235 inches wide

1 inch ÷ 5.5 rows = 1 stitch 0.182 inches tall

Enter the resulting decimals into the width and height fields in the Configure Grid window.  Tip: If one field insists on changing with the other, try clicking the little link icon in the bracket beneath the width and height fields.  When the link looks ‘broken’, try re-entering the decimals. 

Click the OK button in the bottom left hand corner of the Configure Grid window.

10. Nearly Finished!  Because GIMP won’t export the image with the grid, now is the time to pull out your screen shot skills and put them to use.  Take a screen shot of the image inside the editing window and save it in a printable format somewhere on your computer you can find it, e.g. a .pdf on your desktop.

11.  Find your newly created .pdf and print it.  That’s it.  Your chart is done.  Each square is equal to one stitch.  If some of the lines are difficult to see, use a ruler to go back over the lines with a pencil.

 The next tutorial will deal with turning a still life photo into a chart.

Happy Knitting!

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