photo's

[DonC]

A couple of general points about digital pictures.
Most cameras will use the JPG format to make digital photos readable. This is probably the most common of the photo formats. JPG is a compression algorithm that reduces the actual file size with only a slight loss of quality while creating a significant reduction in file size. In general the original JPG file without modifications can be used in emails and for posting on web sites and will give a reasonably good picture.

Where the problem starts with JPG files is when you modify it by either reducing it in size, crop it, or make modifications to improve the “viewability” of it by changing contrast/brightness, color cast, red eye removal etc. and then resave the file in JPG. When you do this you’re compressing and already compressed file and your image quality starts to degrade.

If you’re going to do any manipulation of the photo save the original in an uncompressed format such as TIF or BMP first THEN do your manipulations. Once that is done resave the file in JPG and send it to wherever. This reduces the recompression degredation.

If you’re scanning a photo for use as a digital file scan it in TIF format first if at all possible. Again, do any manipulations in that format before compressing it into a JPG for distribution.
As for DPI or PPI ( Dots Per Inch or Pixels Per Inch, these terms are generally used interchangeably) keep the original in as high a DPI/PPI level as practical. 300 DPI/PPI is the preferable depth for serious printing. For use in an email or to post on a web site anything above 72 DPI/PPI is USELESS. This is because of the limitation of computer monitors to see much above that value. There is a freeware program called IRFANVIEW that has one of the best downsizing algorithms out there for reducing pixel depth and photo size from whatever the original is to something that’s useable on a web page or in an email.

Just some basic information for getting started in the digital photo realm.

DonC