: How to make blue color transparent on the heatmap in inkscape? I would like to remove the blue color and make it transparent, sort of removing the background. The heatmap looks like this:

@Connie430

Is it really a vector graphic?

There are two types of images, vector and raster. Inkscape is a vector graphic editor. If it's a raster graphic, Inkscape is not the appropriate tool to use.

Vector graphics have extensions like SVG, EPS, and PDF. But extension alone isn't helpful since most vector formats can also link or embed a raster graphic.

Check to see if it's a vector image

A quick test is to try to un-group the image. Select the image in Inkscape and press Ctrl + Shift + G repeatedly. If it breaks apart into separate pieces that you can drag and move around, it's a vector image. If it doesn't break apart into separate objects, it's a raster image. You can also see this by selecting your image and pressing F2 to view the object's nodes.

If it is a vector image, un-group everything, select the blue, and delete it.

Use GIMP instead

Don't use a screw driver to chisel wood and don't use Inkscape to edit raster images. GIMP is the most ubiquitous open source image edit. On the commercial side, there's the popular GIMP alternative called Photoshop.

There are a variety of ways to select and delete things in GIMP. The Select By Color tool or the Fuzzy Select tool are good options here. The GIMP User Manual has a tutorial for removing backgrounds that would also be good reading.

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@Reiling762

If generated with a reasonable plotting program, the heat map itself is almost certainly an embedded pixel graphic – because that’s one of the things pixel graphics are good for. However, Inkscape is not good for editing pixel graphics.

Hence, the best way to deal with this would be to extract the pixel graphics and load it in a pixel-graphics program of your choice (e.g., by copying and pasting), which hopefully has resources to manipulate colours the way you like. Changing colours in the way you describe is also something that can easily be done with a small script in any programming language with a reasonable interface to handle pixel graphics (e.g., Python).

Once you did this, you can replace the heatmap in Inkscape.

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@Sarah814

If the image is integrated with all the elements (one element, JPEG or PNG), you can only manage their general opacity. However if the elements as the left scale, can replace the background and you can manipulate the opacity.

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