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+--- Thread: Dot for Dot and Monitor(screen) Resolution (/Thread-Dot-for-Dot-and-Monitor-screen-Resolution)
Dot for Dot and Monitor(screen) Resolution - rich2005 - 08-17-2017
Want to print an image and check what it looks like at actual size?
By default Gimp has View -> Dot for Dot enabled. see: https://docs.gimp.org/en/gimp-view-dot-for-dot.html
This is because Gimp is a bitmap/raster editor and works in pixels not real world (inches/millimetres..) units. With Dot for Dot ON each image pixel equates to one screen (monitor) pixel.
This is a photograph of my laptop. I made a new image 100mm x 100mm at the default resolution 72 pixels-per-inch (ppi)
Important, keep to a zoom value of 100% to see correct comparisons.
When View -> Dot for Dot is ON
[attachment=690]
From the ruler it measures about 45mm square, Gimp uses pixels, there is a tiny rounding error when looking at Image properties, 100mm becomes 99.84mm nothing to be concerned about.
when View -> Dot for Dot is OFF
[attachment=691]
The canvas. 100mm x 100mm now measures the correct size.
If only it was that simple:
What you see very much depends on setting Gimp up correctly. Edit -> Preferences -> Display
Modern monitors and especially laptop screens might have a high pixel density. These are the values I use for my laptop.
[attachment=692]
Gimp thinks that the correct Monitor resolution is 96 ppi
Calibrate is generally broken with Gimp 2.8.x (much better in Gimp 2.9.5)
You can calculate this using / before after proportions or a bit of trial and error to obtain a value.
Why work with Dot for Dot ON
Back to Gimp is a pixel editor, when ON you have control over each pixel, when OFF Gimp will decide which pixels are changed.