Resolution and PPI

I’m wondering if in RT is possible as in GIMP to view the effective printing dimension when I select 100% of zoom.
This could be useful for who prints his images to evaluate how it could be the effective dimension.
I find this very useful for not to waste time in trying to get what you can’t view on print…


Ciao Gabriele!

Would the information under Crop be sufficient?

Cordiali Saluti,
Claes a Lund, Svezia

Hi Claes,
I’m not clear when I speak another language :confused: I mean I wish to view on the preview the dimension of printing when I set 100% of zoom.
In GIMP I deselect the dotxdot option in view menu and I view the effective image I’ll view if printed.

Sí, claro!

But that was the best idea I could come up with :slight_smile:

@dafrasaga I don’t know this option in GIMP, but what do you mean by ‘effective printing dimension’? There is no such thing. The connection between resolution and print size is totally arbitrary.

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That’s what I thought as well. You have a certain quantity of pixels and it’s up to the user how many pixels per inch you send to the printer. The higher the ppi, the smaller the print, and vice versa.

Hi Thanatomanic,
I mean I can view on monitor how the images will be when printed by a specific resolution… I explain

GIMP detects the effective monitor resolution


if I remove the flag “dot for dot” in the view menu

set the print resolution (300 dpi; good for eye viewing)


in the preview, with a 100% of zoom, I can view the image as I view it printed at 300 dpi on the wall at that distance.

Hello @dafrasaga, there’s an inconsistency with your screendumps. Look at the Set print resolution, at 300ppi the print size is about 20x30cm.
Then look at your preview window, there (bottom left) it says that the print size is 4x7,8cm!

If I want a preview of the photo that will be printed, I type Shift+Ctrl+J in Gimp. In A/RT I type ‘f’. When the number of pixels of your photo exceeds the screen dimensions, it will be automatically scaled down to fit on your screen.

@paulmatth Oh? You mean 40.47, -7.79? How about present cursor coordinates? (Minus because the cursor is located above the image.)

For clarification - this is a screen dump from the dreaded Photoshop :dizzy_face:

In Ps we have ‘photoshop inches/cms’ which are NOT the same physical size as REAL WORLD inches - this is solely due to the users/viewers screen ppi and nothing else.

In this case I’m on a 27" Eizo with a screen resolution of 109 ppi but the image is 300 ppi - see the problem there??

GIMP will be the same I’m sure.

So Ps give you the facility in Preferences>Units & Rulers to basically ‘program’ Ps with your monitor ppi resolution - hence clicking View>Print Size it drops the view magnification down to the point where screen inches and real-world inches are the same!

But you don’t have to have that facility - all you need to do is divide screen horizontal ppi by image ppi then x100 and that gives you print view - in this case 36.33%.


Hello Claes, I think you’re right here, those must be cursor coordinates indeed…

Yes, Those are cursor coordinates…
If measure the image on the screen I find it’s 29 cm large as it’s printed at 300 dpi (3469px300=11.56 x 25.4mm=293.71 mm)

Therefor I view the image as hanged on the wall… In this way I can save time in post processing to find things I can’t view when normal viewing :face_with_hand_over_mouth:


Yes as I said GIMP is the same in preferences

Would be very useful for who prints his images to have such thing in Rawtherapee , in my own believe :slightly_smiling_face:

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Top Tip for anyone who is interested.

Only set 300 if you are sending to a Canon printer. If you are sending to Epson then change it to 360.

Canon print head resolution and Epson print head resolution are different - Canon print drivers work in base 300, Epson in base 360.

Sending 300 through an Epson driver to print at 2880dpi will cause artifacting on the print - guaranteed, and more obvious the bigger the print.

Any other printer, Lexmark etc, just check the head resolutions.