Image & Canvas sizes won't 'stick'. They keep reverting

[johnivanwhite]

Hi All,

Do any of you know why this is happening?

I set up a document at 220 x 285 mm but when I check the image and canvas sizes, afterwards, they’re different!

I try changing them in image size and canvas size, but they still revert back. Very annoying and weird!

My Unit Sizes/rulers in Preferences are set to Millimetres. Does it have anything to do with the image resolution (surely irrelevant) being set to Pixels per inch?

Thanks

John

[davescm · Accepted solution]

Photoshop works in pixels. So the nearest document size to 285mm in whole pixel numbers (you have set 300 pixels /inch) is 3366 which takes up 284.988mm

Dave

[johnivanwhite]

Ah, so it'll never be precisely what I set?

And if so, when it goes to print, with the placed Photoshop image set at exactly 220 x 280 mm in InDesign -- it'll be such a small distortion as to be neglible/undetectable?

[davescm]

You've got it. Like I say Photoshop works its canvas to the nearest whole pixel.  As far as the difference is concerned - if you can see .01mm you have better eyes than I have .

Dave

[johnivanwhite]

That makes sense, Dave.

It's funny that I've never noticed this before. Unless it's a new thing in Photoshop, in that they show us a more honest/realistic measurement than previously.

[davescm]

If you normally work in inches you wouldn't see it - as, when you set a value in pixels per inch, it works out exactly to the inch in whole pixels. So that may be the difference. You can of course set resolution in pixels/cm

Dave

[johnivanwhite]

That's a good suggestion, but it's unlikely I ever worked in inches for print to be honest.

Thanks for the help Dave

John