92 Technical Issues: Killing the Gremlins
almost invisible; but as the quality settings are reduced, more data are
discarded in the quest for a smaller fi le size.
Unfortunately, the effects quickly become apparent to image
inspectors and, worse still, the compression artifacts increase each
time a JPEG fi le is saved. This is one critical reason why it is
worth converting a JPEG format fi le from your digital camera to
a TIFF format, preferably a 16-bit TIFF format, while you are editing
the image data. Only convert back to JPEG when you have
fi nished editing your fi le and are ready to submit it to your microstock
library.
Some noise-reduction programs can be set to reduce JPEG artifacts,
including the built-in noise-reduction fi lter in Photoshop (mentioned
earlier). However, I have found they rarely work well. Avoidance is
better than any cure.
In summary, my advice to avoid or minimize artifacts is the
following:- Use raw format whenever available.
- Use the highest in-camera JPEG settings.
AB
FIGURE 5.11A and B Two small sections from a larger image. A clearly shows JPEG artifacts on sharp edges. Avoid this at all costs!