Argh!

iStock rejected my submissions.

The stated reason for each of the three was:

This file contains artifacting when viewed at full size. This technical issue is commonly created by the quality settings in-camera, in post-processing or in RAWsettings. Artifacting may be the result of other factors such as excessive level adjustments.

I said “no way – those images are great”. Couldn’t believe they found “artifacts” – these were RAW images, never seriously compressed or post-processed.

After being dejected for a while I went on the iStock forum and did some searching on the subject. I realized there were two possible reasons for their response:

1. Sharpening. I tend to like to sharpen, sometimes a bit heavy-handedly. It improves the pop when printed on my Epson, and helps maintain crispness when resized smaller for the web.
2. Chromatic aberration (CA). CA is a by-product of the way light bends as it passes through glass. Different wavelengths (colors) of light bend differently when they pass through the air-glass boundary. This is how white light separates into a rainbow when it passes through a prism [illustrated in classic rock style here]. CA is more likely to occur in inexpensive lenses, but it happens in good ones too. These photos were shot with a Nikon 18-200 zoom – a flexible and useful lens for walking around, and considered very good (both Thom Hogan and Ken Rockwell like it a lot), but obviously it suffers from a little CA.

So I re-opened the raw images, didn’t sharpen them at all, and did some careful correction to minimize the CA. Resubmitted them and now…well…I guess I have to wait another 4 weeks.

Kind of an enthusiasm damper.

On the other hand, anything worth doing is worth doing well. I should probably be glad iStock is kicking my butt.

This entry was posted on Thursday, December 18th, 2008 at 4:50 pm and is filed under Photography. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.