Create high-res (300dpi) images from Excel charts and plots

By |

If you need to create a high resolution image of your Excel chart for a manuscript/journal then the usual cut & paste approach generally only leads to a poor quality 72dpi image often with a bad case of the jaggies.

A Solution

Here is one, relatively straightforward way around this problem. It uses a graphics program called IrfanView (IV) which can be downloaded here . Other imaging programs such as Gimp and Imagemagick can also be used but I’ve found that IrfanView is the easiest for this process.

Once IrfanView is installed you need to configure an option as follows (this only needs doing once)
From the menu: Options:: Properties/Settings :: Select Plugins in lef-thand list :: ‘PDF Options button :: In loading options, select Use(new).. and ‘set DPI’ change from 96 to 300

  1. Now generate your chart/plot in Excel and resize as desired.
  2. Open a new blank presentation in Powerpoint
  3. Copy the desired chart(s) in Excel
  4. Paste-Special the plot(s) into Powerpoint, one to a slide. The key this here is that you paste it as an Office or Excel chart/image object
    1. File/Save-As PDF
  5. Run IrfanView and open the PDF file created above (dragging it into the open IV window is easiest)
    1. Now repeat the following steps for each page/image:
      1. File/Save As and select JPG
      2. A pop-up options window will appear – use the ‘slider’ to set the quality to good then click save

To check that this has worked, find your newly created jpg file in Windows Explorer and right-click on it. Select Properties and then select the Details tab. Scroll down a bit and check that both the horrizontal and vertical DPI setting is 300.

Background

BMP, JPG, PNG & GIF are all RASTOR image file formats which is a grid of pixels – (x,y) coordinates each describing the colour of a dot at a particular location. These are commonly used for storing & displaying photos. The problem is that when they are over enlarged the quality can deteriorate and straight lines can become jagged.
VECTOR image files on the other hand store the mathematical equations of the components that make up the image (e.g. lines in a graph) and so can be enlarged as much as desired without any loss of quality.
Vector files tend to be much smaller than Rastor files however they generally need converting into rastor files before they can be used – e.g. on a web page.

 

If you have a better/simpler way of doing this please add a comment below or email me and I can update this post. : j.a.allen@kent.ac.uk

Leave a Reply