I am making figures for a report that require stacking a few scans on top of each other. The program that processes data allows you to export the spectra as a bitmap file. I have been placing them into a word doc to move them off of the computer attached to the instrument (not connected to internet). I then put them on my computer, save each image as a pdf and export them into ai. The scans look like this:enter image description here

I want to extract just the line and place several on one image to compare but I can't figure out how to do that. Trace ends up somewhat lumpy and I can't change the color of the line or isolate it as a single object. Is there another way I should be exporting the scans? Or another tool in illustrator?

  • Can you export the numeric data? – joojaa Jan 23 at 17:53

There are several related questions on this site: 1, 2, 3.

The problem is that such a low res image can't easily be autotraced to vector. If you need it to be vector, you might as well trace it manually point by point, but it takes some time and it might be impossible to see the individual points.

Ideally you should export in a vector format if possible or export the data points and create the graph from them in another program like Illustrator. That would make it possible to isolate the line as a single object and choose a color for it.

If a raster format is the only possibility and scalability doesn't matter, you should try to export an image at the highest possible resolution. Don't place it in a Word document as it compresses and scales the image. Just save it as a file.

Illustrator isn't really the best tool for editing raster images. Instead use Photoshop. For example, using the inverted image as a Layer Mask on a Solid Color layer makes it possible to colorize the graph as you like, like this:

(There are many questions about coloring grayscale images on this site if you need help to get started.)

Unwanted lines and labels must be edited away manually with a brush.

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