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+--- Thread: Dot for dot (/Thread-Dot-for-dot)
Dot for dot - gimp-artist - 05-12-2018
Gimp doc says "When view>dot for dot is unchecked the image should be the real size if the image resolution is the same as the screen resolution.", according to this attachment.
[attachment=1717]
I measured my monitor vertically. I divided it by 1440p, which is my display setting. The result ppi is approximately 109 ppi.
I opened a blank new image sized 640x480 with 109 ppi resolution.
Then I unchecked the "dot for dot" in view menu.
I measured the vertical size of the image. The size is smaller than 480/109. It should be 480/109.
So, I checked the "dot for dot" in view menu. Then the size is 480/109.
Why is this happen?
RE: dot for dot - rich2005 - 05-12-2018
This is all about printing and print resolutions.
Two images both 300 x 300 pix no.1 @ 300 ppi and no.2 @ 150 ppi. with dot-for-dot off (default setting) both obviously show the same size (zoom being equal)
With dot-for-dot off their printed size will display
no.1 = 1 inch (300 pix/300 ppi)
no.2 = 2 inch (300 pix/150 ppi)
comparison see: https://i.imgur.com/gnvMsVp.jpg
If your monitor is correctly set up, then you can measure these values on the screen.
This is my laptop, has a HD display, and a pixel resolution of about 157 ppi
Edit -> Preferences -> Display see: https://i.imgur.com/mX1bmIZ.jpg
There is a calibration page to assist, not very good in Gimp 2.8. Automatic does not always work, a know problem that has been fixed in Gimp 2.10. Try it but you might have to do a bit of measuring on the screen and arithmetic to get the correct screen pixel density.
calibration looks like: https://i.imgur.com/JaZvGC5.jpg
RE: dot for dot - gimp-artist - 05-12-2018
Yeah, like you said the automatic ppi is not correct. I've decided I trust what I measured. I manually changed the ppi in preferences. Then all works fine.
I haven't upgraded gimp to 2.10. I'm planning to upgrade it after reading all the doc pages.
Thanks for the help.