Mac Preview

[corinne]

Hi

I was wondering if someone could help me. Firstly I am using a 450MHz G4 with Mac OS X version 10.3.9.

I have to look at lots of various images for my job and because I work for a publishing company I have to check the DPI of the image. Recently I have been having problems with Preview which is the only application I have that can open images. Recently it has started to wrongly identify the DPI of certain images. When I open them in Preview it states that they are 72dpi even though they are large files. I then send them to a colleague who has Photoshop on a PC who opens them and they are 300DPI. So to clarify when my colleague and I look at identical images my mac states they are 72 dpi and his pc states that they are 300dpi.

I was wondering if anyone could tell me why it is doing this and what I can do to correct it.

Many Thanks

Corinne

 

[searay345]

Hello corinne and Welcome!

I would try repairing your disk permissions. Usually doing that will fix those types of errors. Go to Applications --> Utilities --> Disk Utility --> Select your Macintosh HD drive and click on Repair Disk Permissions. After that's done, restart your computer. Let us know if this helps you out at all or if you need further assistance.

Cheers from the 18*F in Michigan
Searay

 

[Ric]

Hi there Corrine and welcome !

Preview has had problems like this before...

Check in Previews preferences and see what settings are selected...in the images tab.

Is "Respect Image Size...." selected ?

What is "Default Image Size" set to ?

regards

Ric

 

[Kyomii]

72 DPI (720x480) is the standard resolution that photo software displays images via a computer screen NOT the actual DPI of your photograph, and not the resolution of your monitor.

It is recording as 300 dpi on your friend's system because it is likely he has printed out from that program and has set the standard display resolution to 300 dpi.

The picture will not look any different though on your monitor to your friend's - infact you could set your photo software to display the image at 10 dpi and you would not notice any difference simply because a computer screen/graphics does not really know what an inch is as such - it deals with pixels, not inches!

Even my Canon 20 D 8MP camera displays at 72dpi once viewed on the computer - it is nothing to worry about as long as you change to 300dpi (via the photo software) before printing!

It is the first thing that should be changed before printing any photo out via any photo program - 300 dpi is recommended, then you can set your printer settings to print out at a higher DPI of what it is capable of without losing much detail.

Check the settings as Ric suggests, and you should be able to alter it from there, although you will not see any difference, it will save time if you want to print from preview.

You can trash the preferences file for preview, but that will take it to 72 dpi as it is the standard/default setting.

All in all, it is just a default setting used across the board of different photo editing software packages/viewers and nothing to worry about.