Look at the number after the file name at the top of the screen.

16.7 million color image

If this figure is 256 or 16.7M your image is grayscale or color, even if it looks black and white!

If you try to vectorize a grayscale or color image there are three likely outcomes:

The vectors look like crazy paving.
OR
There are no vectors at all.
OR
There are just a few straight horizontal and vertical vectors around the drawing edge.

A technical explanation

By default, Scan2CAD vectorizes every non-white pixel it sees on a white background. It does not vectorize white pixels.

Sometimes a background that looks white is in fact very slightly non-white. Maybe it's criss-crossed by non-white areas leading to crazy paving vectors, or maybe it's completely non-white leading to no vectors at all.

In a 256 color image 255 of the colors are non-white. Now imagine an image with 16.7 million colors where only one is white! You can see how easy it is to end up with a non-white background!

The problem is particularly likely if you are converting JPEG files because JPEG is a color only raster file format.

Solutions

  • Use Thresholding to reduce the colors on the image to black and white:

    1. Click to do a Simple Threshold or to do an Adaptive Threshold. If a Threshold Information dialog appears, click Yes to continue.

    2. Move the slider(s) to a position where the lines on your image are as solid as possible and the background is as clean as possible.

      Click the Help button in the Simple or Adaptive Threshold dialog for more information on how to use the sliders.

  • Whiten the image background:

    1. Go to Palette > View/Edit Palette.
    2. Click on the colors that look white so they become selected. (To select a row of colors, click at the right hand end of the row.)
    3. Click on Change To White.
    4. Click on OK.

  • Rescan the drawing using our Scanning Checklist so that the drawing is scanned as black and white (2 colors) not grayscale (256 colors) or color (16.7 million colors).

    After scanning be sure not to save your drawing as GIF or JPEG as these formats will turn your black and white scan back into a color image!

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