Image Quality

Recently, I've had a lot of questions concerning "Image Quality" and different file types of images - jpg / tiff / raw. Here's the techinical lowdown on this topic - taken from one of the tutorials I've written as part of my online photography course.

Maintaining Image Quality - the story on jpgs
For those of you who shoot only jpgs digitally here's a word of caution. First of all we must understand some technical features of image files. ALL jpgs compress when saved every time. The image eliminates un-needed information every time we re-save it to a drive. So, by default a jpg is designmed to loose quality. If you are going to retouch or color correct a jpg, save it as a tiff first, do your retouching on the tiff and then save it back to a jpg again. Tiff files, inherently do not compress and loose information when retouched and re-saved. This is why Tiffs are bigger files than jpgs; they retain ALL the information.

If you do this religiously your jpgs will retain quality. If you don't do this and continually open / retouch / re-save a jpg eventually you'll notice the image quality has been

compromised and has deteriorated. You will not necessarily notice this on your computer screen since digital files retain way to much information for most screens to capture and reproduce, but you will notice it if you try to print it large or provide that image to magazine or publication.

I hope this helps in this controversial topic. These facts are not my opinions. This is technical data that is true of all digital files.

Jeff