Saturday, November 6, 2010

Display aspect ratio of images

I recently purchased a new monitor (an Asus) which is wide screen (16:9). It was my belief that while Windows stretched the desktop, etc, pictures were displayed in their correct aspect ratio (height vs. width). But, the other day I was working in Photoshop on an image and I discovered that what I thought was not true. FYI, I'm going to put the picture that I was working on in another post.


So here are some numbers I got using an old fashion ruler.

First, here is the image size in Photoshop
5.35" High
4.41" Wide
1.21=5.35/4.41 Aspect ratio

I printed the image on paper, using Photoshop
5.34" High
4.41" Wide
1.21=5.34/4.41 Aspect ratio

As expected, the image size in Photoshop and the printed version are the same.

Now the strange thing. I physically measured the image on the screen in Photoshop. Note that the actual physical size can vary, because it depends on how the size slider is currently set. But, I was interested in the ratio of height and width.

7.00" High
7.75" Wide
.90=7.00/7.75 Aspect ration


From this I can only conclude that the image is being stretched horizontally, which is NOT what you really want. I mean everyone will appear to be a little fatter than they really are. So my question is this; how do I control this so that when I have a square box, it doesn't show up as a rectangle? I can't find any setting in Windows to correct for this. Does anyone know how to do this?

4 comments:

Sean said...

Mine measures correctly.
Problem is the monitor or the pixel size you have selected for the display. You should always set the display pixels to the native resolution of the monitor. If you have done this and it is not square the monitor is wrong.

Tommy said...

Sean, that's interesting. I really didn't realize this, but I really should seeing as I'm a computer consultant. My current video adapter doesn't have a setting for the monitors native resolution (1600x900), but I just happen to have a new one on order which should be here next week. Hopefully, the new adapter will be more up to date with these widescreen monitors. I'll post here how this turns out.

Thanks for the tip, hopefully I'll be able to resolve this..

Ray said...

@ Tommy -

What brand of Graphics Card do you have?

Mine is an ATI Radeon and it is used on a desktop PC with an Acer X223w flatscreen LCD monitor having a 16:9
aspect ratio. My native resolution of
the display is 1680 by 1050.

I'm running Windows 7, and in its "Control Panel" there's a link for
"Display" which takes me to a window where I can see the settings
or make changes.

Some Graphics Cards, like Nvidia, have their own "Display Manager" which can be installed or updated like their drivers from their website. Try checking your card's website for downloads/drivers and see if they have something there.

Tommy said...

Ray, my graphics adapter is a Radeon as well, I think the 7600 or something like that. Right now I'm booted to my XP config and it just doesn't have an option of 1600x900. I don't really want to mess up the Win 7 setup until my new adapter arrives. Hopefully then I'll be able to set up correctly.

I haven't totally moved over to Windows 7, but it's coming real soon. A little green man in a flying saucer that I say last night said that I needed to get on with it! :-)

Ray "16:9 aspect ratio. My native resolution of the display is 1680 by 1050."

Unless I'm missing something here, 16:9 doesn't equal 1680x1050. If you do the math, a true 16:9 has a height that's 1.77777777 times the width. But, whose counting. :-)