changing image size

Recently purchased Dig Rebel XTi and was surprised to find that all but RAW files come in at 72 pixels per inch, in large files in terms of inches.
What is the best way of changing such images to 300 pixels per inch and smaller size, say 9 x 12 inches -- ?
I spoke to Canon but their response was incomprehensible.

I see that RAW images come in at 240 pixels per inch which makes me happier.

PPI is not important until it is printed or displayed. As for displaying on a monitor 72ppi is sufficient.

Depending on the S/W use to change image size methods will vary. I work w/ PSCS2 so here is how it is done in PSCS2:

Open image in PSCS2 and goto image/image size.
Make sure constraint is checked.
In the ppi field change to your desired ppi.
You'll see the pixel width and height will change accordingly.

Arcsoft Photostudio may or maynot be included in the s/w provide w/ your camera. You can also use this s/w to adjust image size basically the same way. Goto edit/image size or F2 key.

as lostdoggy said. 72ppi vs 300ppi means nothing until printing. the images still have the same amount of pixels in them at ANY ppi.

lostdoggy is correct. for screen display, 72ppi is sufficient. anything more would yield little improvement and inflate file size (more download time). I have had success with RAW at 300ppi when printing large sizes. i printed a 12x18 black and white print at 300dpi and saw no pixilation. I'm going to try and print a bigger picture in the near future.

Yeap, but Lostdoggy made one foolish mistake and thank you for not making fun of me.
The last sentence should read the dimension in inches should change for width and height.

Not Pixel.

Thanks, and also for your next message.

lostdoggy wrote in post #2392095
PPI is not important until it is printed or displayed. As for displaying on a monitor 72ppi is sufficient.

This isn't really correct. The DPI has no effect when the image is displayed on monitors. An image that is 800 pixels wide will display 800 pixels wide on a monitor, regardless of the DPI of the picture or the monitor (when viewed at 100%, of course).


Also, since this is another point of serious confusion with DPI, the DPI setting of the image does not matter if the printer will print a particular size. That is, many many companies that use "mini-lab" printers (MPix Walgreens Ritz etc etc) will over-ride the DPI, and print a 4x6 or 5x7 or whatever you tell them. These mini-lab printers will resize the image and auto-crop on the fly to get the image to print to the specified size - completely ignoring the embedded DPI.

This is a pretty general statement, so take it with a grain of salt, but if you specify the print size (4x6, 5x7, etc) then you can be fairly certain that the image size and DPI will be ignored, and the image will be automatically resized and cropped to fit the specified output print size.

Again, it's best to confirm this, since this is a very general statement.

Are we talking about DPI or PPI. Most Labs that I have seen prefer files to be at least 200 ppi for the given media size ie 4X6. Most reuqest it to be 300PPI or better.

From your logic if some one sends a file from a 1MP camera in and ask for an 8X10 they will disregard the ppi and print it any way???

Yes, they will. You asked for 8x10, they'll give it to you.

Of course they prefer 300 DPI or more. But they will print your pic at the size you requested.