A question from a client:

“I am needing to understand file size and how a raw file goes from 15mb to a 13mb tif to a 6.2mb jpeg.  And how do you get that raw file to a 24mb jpeg preferably as an 8X12 image. My son-in-law and I are working on a website on Photo Shelter and I am trying to get some images ready to upload.  I am not figuring this out.  I use a program called PhotoZoom Pro for upsizing and I am still not getting the outcome that I need.”

My reply:

“I use, love and recommend Photoshelter highly. Get the Lightroom plugin for Photoshelter and you can export photos directly from Lightroom into your Photoshelter account. You don’t need PhotoZoom for resizing.

The file size issue is not directly related to image resolution. A raw file does not contain pixels per se; its size is based on the amount of data it contains (though it does have a native resolution).

When you convert a raw file to a tif, the resulting file size will be larger, even if the resolution remains unchanged. When you convert a raw file to a jpg, the file size goes down because a jpg file uses compression to eliminate redundant data and make a smaller file size.

To say you need a 24mb JPG is off base. Regardless of the actual file size on disk, what matters are the dimensions (8×12) and the resolution (eg 300 ppi). With JPG, this might still only yield a file of 8-10 MB and that’s fine.

With Lightroom, all you need to do when exporting is enter the dimensions and resolution you want and Lightroom does the rest.

Again, you don’t need any other software for resizing photos.

I’ve been building an entirely new web site of my own, on Photoshelter, and over the past 6 months have used the export plugin to upload nearly 800 photos to my account. It really works.”

Note: stay tuned for the announcement of my new web site launch!

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