Problem with Resize using resize document in 331

[agnesim]

I'm trying to resize an image using the document resize dialog and there seems to be a probem with the new sampling option.

With the new sampling check selected:

If I just change the PPP value with pixels selected as the units value the pixel values in the uper boxes are changed automatically.

If I select units CM and then change de PPP value,(from 96 to 300)  the CM values are not modified in the upper boxes, 
but after clicking OK in the dialog, I was expecting a file with the CM showed in the upper boxes and 300 DPI

But the result is a 300DPI image with smaller height and widht values that the ones showed in the upper boxes of the change image size dialog.  (No new sampling applied to the image)

 

[Dave Quail]

I can confirm this anomaly.

[Gabe]

Hi both,

Why do you think that changing the DPI should change the CM value? The resize dialogue does what you ask. Let's take an image 72x72px, units in inch @ 72DPI. If you open the resize dialogue and set the units to inches, you will have 1 in x 1in and the DPI value of 72.  If you only modify the DPI, it will not change the size in inches, because that's not what you've asked. You've asked for a 1in x 1in image with a different DPI. Changing this to 144 for example will create a canvas of 1in x 1in @144 DPI, which is 144px x 144 px.

Thanks,

Gabe. 

[agnesim]

Hi Gabriel,

That is exactly the problem, the dialog is changing the CM values with out the user requesting this.

I have the issue in CM but to make it easier I will take your example in Inches. I tried your example using the 1x1 inch value and it works fine, the resize is as you explained.
but I took another file with other values and this is what happens, I changed the values to inches to make it easier to explain here.

I have a document 19.29x10.237 inches at 300 dpi.
I open the dialog and change the dpi to 600 dpi
The final document is:   9.645x5.118inch  600dpi.

As you explained I would have expected to have a 19.29x10.237 inch 600dpi file.

Using 1x1 inch in my test does not make this strange size change. try with diferent file sizes.

(Tested in version Beta 333)

[Ron P.]

DPI does nothing for the physical size (inches) of an image. DPI=Dots Per Inch, which is exclusive to print media, not display such as screens. I done a quick screen recording demonstrating this. I can change the DPI clear through the spectrum, and the inch size does not change. However if I set the units to Pixels, then the DPI is really PPI, which is Pixels Per Inch, thus the screen display size changes, not the print size.

 

[agnesim]

I  do not know how to save video but I have attached 3 files with the problem.

Image 1 Open document size window, original image DPI 300 DPI

Image 2 changed resolution form 300 to 600 and clicked change size button.

Image 3 open again the Change document size window.

When I was trying to do this in my test I noticed that this did not happened in a blank document 30x30 cm.

So I opened a random image and there was the problem.
Also If I modify the DPI again from 600 to 300 DPI  the CM value is now preserved.

Will post the 600 to 300 DPI photos in another post to avoid confusion.

[agnesim]

The problem did not happened when changing from 600DPI to 300DPI

This is a follow up from the last post just splitted the post in 2 parts to avoid confusion.

Image 1 original DPI 600 DPI   (From the already modified file in the last post)

Image 2 changed resolution form 600 to 300 and clicked change size button.

Image 3 open again the Change document size window.

Now the problem is not there. the CM values where respected.

 

[Gabe]

I cannot replicate this either. Can you perhaps use a free screen recording software? ( Tinytake perhaps? https://tinytake.com/ )

[agnesim]

Tried the issue in the RC2 beta and still does the same thing.