RAW file question

[RepGurl]

I recently got a new camera and I am now taking my pics in RAW format. When I open a RAW pic on the computers on campus using photoshop CS2 they open at the following size:
2592 X 3872 pixels
8.64 X 12.907 inches
300 dpi

However when I open the same image with my computer at home using photoshop CS3 it open like this:
2592 X 3872
10.8 X 16.133
240 dpi

Anyone have any idea why this is happening?

 

[David Loftin]

So the pixel size is the same, because computer monitors have a visual output of 72 pixels per inch. 300 or 240 is print resolution, something that you dont really need to deal with unless you are printing something, at which point you would crop or resize it based on your needs.

 

[nats]

Here's a stupid question, what does "RAW" mean?

I am assuming it is the original size when downloaded to a PC?

 

[PacHerp]

Here's a stupid question, what does "RAW" mean?

I am assuming it is the original size when downloaded to a PC?

RAW is an image format(almost every camera has a different form of RAW) - it is basically like a digital negative. It is an advanced form of capturing images and records 100% of what the camera sensor sees. It gives you much more information to work with than RBG formats such as .jpgs, .tiff, etc, etc.

Hope that helps!

 

[RepGurl]

I am printing, that why I care. Im a graphic design student, so the question is not just for gecko pics but all my pics. I have asked a few professors and they dont seem to know why they would come up different. I understand that the camera is enlarging the size of the pic and scaling down the resolution to match but why would it do that? Why not just show them at 300 dpi. I want to print with the highest resolution I can, but when i try and scale the pics back down so they will be 300 dpi again it does not change the size of the pic (so in effect it is stretching the pixels some unnoticeable until I print amount).

 

[bleeding_sarcasm]

The simple answer for "why would they do that" is that different versions of the same program are going to have different defaults. The default print resolution on CS2 is 300, on CS3 is 240. To change your default go to the apple menu > preferences > units and rulers > change your print resolution to 300 dpi. (or whatever you want) on a PC it is edit > preferences > same as above.

But in all honestly, you are going to be doing enough post-processing in photoshop before printing, that it really only takes a minute to re-size the image to the correct size and resolution. If you are printing, it is unlikely that you are just printing off of the photoshop defaults.

I would suggest you look into taking a digital printing class (I used to take printing for digital photographers) I would ALSO suggest that if you are interested in getting into printing your digital images (pictures or others) that you check out the series "from the camera to the printer" on http://luminous-landscape.com/ (they have a lot of really excellent tutorials)

So you are never going to get a bigger SCREEN resolution then 72dpi (unless you have like an HD screen + a rockin video card). Any changes you make on the screen wont be visible to you, until you print it. 300 is the standard printing size, but 240 is an acceptable printing size if you are doing a large print that will require people to step back a bit. When it comes down to having to re-size the image (interpolate) Photoshop can only create so many pixels and still give you a decent print.

With a decent printer, you can get up to like over 2,000 dpi, but that is truly unnecessary, as you will end up with an image that is like 3" square, or a bunch of JPG artifacts.

There is a point where if you need to considerably blow up an image, that a smaller resolution will be preferable.

So when resizing your image:

If you type in 300 in the dpi (technically pixels per inch or ppi because you are on a pixel or bitmap based medium) and if you have "Resample image" clicked, then the size of your image (printed, like 8" by 10") will stay the same, and Photoshop will add pixels to fill in the space, so that you have 300 ppi in that size.

If you UNCHECK "resample image" and now change the resolution, it will NOT add or subtract pixels when you type in 300dpi, instead it will change your print size (From 8" x 10" to something smaller)

Another way to cheat, and make sure that your image is the correct size and resolution from the start, is to open a new file, and fill in your required data, then drag your content to this new file (You should never be editing your original files anyway)

Sorry I was signed in as David when I responded to this originally, stupid shared computers!

I hope this helps.