Digital Files / Information

If you are reading this as part of the Beginner Online PhotoShop Course there are a couple of things to understand before you read through this page. This information is offered as information only, and I'm not recommending at this point in your photographic / Photoshop education that you switch file formats that you are presently shooting with your digital camreas. It is important, however, that we understand that the common JPEG file format is NOT the only one, nor is it the best one, nor do we want to use it forever. Exposing you to this info now helps us understand some the things we do in PhotoShop with our images

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File Types

JPEG
Acronym for Joint Photographic Experts Group that describes a digital image file format standard in which the size of the file is reduced by compression. A JPEG image file name carries the extension "jpg". JPEG compression is "loosy", meaning it looses some image information as opposed to other formats like TIFF. A "high quality" JPEG file looses less than a "low quality" JPEG file.

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Image Quality

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 that all jpgs compress when saved, eliminating un-needed information. So, by default a jpg is designmed to loose quality. If you are going to retouch a jpg, save it as a tiff first, do your retouching on the tiff and then save it as a jpg again. Tiff files, inherently do not compress and loose information when retouched and re-saved. If you do this religiously your jpgs will retain a fair amount of 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. You will not necessarily notice this on your computer screen since digital files retain way to much information for most screens to capture, but you will notice it if you try to print it large.


Resolution -

Resolution relates to the number of pixels in an image. The finer the resolution the larger the number pixels will be; and the larger the file size will be. Digital files are like a patchwork quilt, if you can image a bunch of 1 inch squares of fabric in a quilt being sewn. The quilt is a picture of a rose that extends from side to side. Each pixel is equivalent to one 1-inch square of fabric. The color and the location of each individual square is recorded in the binary number system. Put all these numbers together in one long string and you have a digital file. The size of this file is determined by the number of squares. It makes sense that if this quilt were 10x10 feet we would have a fair amount of squares (pixels) in the total file. However, if this quilt were 50x50 feet and the squares were the same size it would have 5 times the amount of pixels; thus, five times quality and clarity. The more pixels (squares) the more detail is possible but also the larger the file.

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RAW Files

The main thing to remember about RAW files is first of all what he mentioned about it being a facsimile of the digital negative. Secondly, this RAW format is the closest duplication of information you can get from your sensor. Thirdly, most RAW file formats are archival, meaing you can't mistakenly to a "file-save" and write over it; thus loosing it permanently.
The habit he has developed about immediately producing and saving a CD of his raw files is an excellent idea also, computer hard drives are NOT archival and crashes do happen.

So, all that being said here's my take on it.

1 ) I shoot everything on RAW; if it's not worth saving is it worth shooting?

2) When I do shoot jpg I'm certain there will never be any other application of images other than personal use, i.e web, email, small prints for a scrapbook.

3) I also always make an initial determination about retouching before I shoot. If I feel there will be some retouching I will shoot RAW regardless of the end use.

Why? Even personal use photographs might be printed.. and even if it's for my mother for her refridgerator I want it to be as perfect as I can make it .... after all, isn't that what we do as pros?