Overlayed arrow looks great, when "drawn" it looks pixelated

Hi Everyone,

Thank you for your help in advance.

I am trying to draw arrows in zoomed-in high resolution microscopy images. The arrows look great when I first overlay them, but when I hit Ctrl+D, the arrows become pixelated. Has anyone else had similar issues and found a work around?



Welcome to the forum, @timmymath!

The Draw command alters the pixels of the underlying image to match the overlay. It cannot “burn in” the arrow at a higher resolution that that of the image itself. Two workarounds I can think of:

  • Save as TIFF. The overlay will be embedded as metadata, and restored when you reopen the TIFF file. This solution will only help you within the context of ImageJ though—if you need the arrow to be present when using the TIFF from other software, you will still have to burn it in.

  • Scale up the image before burning in the overlay. This will require more memory. But you can then Draw the overlay at the higher resolution to which you resampled the image.


I addition to the already made suggestions from @ctrueden you can also draw your arrows and add them as an overlay (Overlay-> Add selection…).

If you then flatten the image (Overlay->Flatten) you get an antialiased (smoothed) image of your drawings as an presentation image.

See: http://imagej.net/docs/guide/146-28.html#sub:Flatten-[F]