Help with Canon CR2 RAW files

I need to adjust/convert RAW files to 8" x 10" at 300ppi but am having trouble finding a program that will let me view/specify the PPI settings. I don't have any commercial software. The Canon provided software doesn't have that option and have tried a few free photo-editing programs but no such luck. I actually need these to complete my application to a processing studio so I can use their services.

Any help or suggestions would be much appreciated.

You are referring to what is a resolution tag and it's rather meaningless. It could be 72PPI or 180PP or 300PPI, but it doesn't have an inherent meaning, only what you could produce with the number of pixels you have at your disposal. Work with pixels! For example, let us say you have 1000x1000 pixels to keep the math simple. And to simplify this further, let's only consider the horizontal axis. If you have 1000 pixels and divide that by 72, that is, you provide 72 pixels per inch, you could end up with 13.8 inches using that division (1000/72=13.8). Let's now say you divide up your 1000 pixels using 180 instead. 1000/180=5.5. In both cases, you had 1000 total pixels. The document itself doesn't have a size, other than what space it takes up on your hard drive. The sizes above are examples of what could be produced if you divided up the total number of pixels you have, with some number of which is just a tag within the document. In Photoshop, if you use the Image Size dialog, turn resample OFF (do not allow it to create more or remove pixels), you can enter any value, 72, 180, 1000 into the resolution field and the resulting size is calculated for you. But you haven’t changed the document or the data at all. You just changed a theoretical 'size' if you output your 1000 pixels using that resolution. So again, it's meaningless until you output the data. At that point, lets say you print the image, you can decide how big you wish it to appear and/or how many pixels you want to devote to the output. You have 1000 pixels and someone tells you that you must use 300DPI (which isn't true but that's a different story). 1000/300 would produce a 3.3 inch print. You want a bigger print? Lower the DPI (within reason). You set the DPI for output to use 180 of your pixels to produce 180DPI? You get a 5.5 inch print (1000/180=5.5).

 

Work with pixels. That's a fixed attribute of the data unless of course you resample that data (add or remove pixels).

Since you titled this thread "Canon CR2" you must be using a Canon camera. Canon cameras, excluding some PnS cameras, shoot photos in a 2:3 aspect ratio. I.e., the image is 2 units high by 3 units wide. An 8 X 10 print has an aspect ratio of 4:5. To make a 4:5 image from a 2:3 image, you must either leave white space on two sides, or you must crop some of the original.

 

You can't just adjust the numbers to get a 4:5 image from an 2:3 original.

Charles, Canon dSLRs all have a 2:3 aspect ratio but there are plenty of other cameras they make that don't and that do output CR2 files.

 

What Craig should do is ignore DPI settings as suggested above, crop to the proper aspect ratio (8x10 or 4x5) and create files without touching resolution (pixels).

Craig, as DD said the PPI setting is totally meaningless. Pixels don't have any size until viewed on a monitor or printed.

 

The PPI requirements between monitor viewing and printing are almost always entirely different. So ignore ppi adjustment and just use the printing dialogue box to setup the size of print required.

 

Most printer drivers allow a "fit-to-page" option, or to specify a print size. The only thing you have to watch is that you don't distort the image by specifying a print size that isn't in proportion with the camera frame ratio. Using "Print Preview" should show you any distortion problem before wasting ink.

 

If you need a decent image editor, the free open-source GIMP (GNU Image Manipulation Program) can be downloaded from www.gimp.org

 

There's a RAW plugin for Gimp dowloadable from here

Unfortunately it's a lot more geeky to use than Gimp itself.

 

Another option is to use the free "Irfanview" image viewer. It will open almost any image file ever made and has cropping, resize and print ability.

Edited May 8, 2017 by rodeo_joe|1

Too late to edit, but PS.

A camera RAW image will not have any PPI tag. It's raw data from the camera and needs processing. That's the whole point of shooting RAW, and probably the reason why Canon's software won't allow attaching a ppi tag to a CR2 file.

 

The file needs to be exported as a JPEG or preferrably a 16 bit TIFF before you can attach ppi tags and suchlike.

 

FWIW, I don't think sending a RAW file off for printing is a good idea. The printer's software might have a completely different idea of how to interpret the data than your own software and monitor.

DO not send a raw file. The lab will likely reject it; you need to render it as you desire.