miricle04 wrote:
Hi. I am using Aperture 3. I shoot pictures in RAW. I have a couple of questions. If I export a RAW photo as JPEG and then re-export that same image as a TIFF do I lose any quality? I like to put some pictures on my iPad 2 as JPEG. I then would like to re-export those same images as a full resoultion TIFF for back-up.
The JPEG quality will depend on what you select for the compression in the Image Quality slider (higher number = less compression and generally means better quality, but larger file size on disk). The TIFF file won't be compressed and therefore you will get the full quality of the Version you see in Aperture.
In both cases, you are most likely discarding information from the RAW file since you are working with a rendered file that was run through the OS X RAW decoder. Since RAW is proprietary, it may be that some information is not being decoded fully by OS X. Most people would recommend backing up the RAW files for future use.
Also, in the Aperture-Export Preset Pane, under TIFF it says 72 DPI. Should I leave it at that or change it to 300 DPI?
The DPI will only matter when printing really, although image viewing programs (e.g., Photoshop) will use the DPI information as PPI and display accordingly. The image size in inches / mm will be smaller than if exported at 72, but printing at 300 DPI will have a significantly better print quality at 100% or under size. I think the decision depends on what other program(s) you would use to change the DPI or PPI settings and how it or they compare to how Aperture's results.
For my part, I export at 150 - 300 depending on my end use since I like the way Aperture handles the math.
Hope that helps in some way. đ
