If you want better scores, you have to make your images look better.
I've noticed that about 50% of the images I've rated this week are only about 49KB in size. Most of those have visible JPEG artifacts. (That's a bad thing, folks, in case you didn't know. JPEG artifacts are a result of the high compression levels "throwing away" parts of the image data.) The smaller in file size you squeeze the image, the more data is thrown away and the worse your image begins to look.
You are allowed up to 150KB for your challenge images. Please use as much as you need to get a good image. Preview the JPEG image as you adjust the quality setting to a level that doesn't introduce patchy areas in large flat areas, and doesn't dull the sharpness of important features. 150KB should be PLENTY to eliminate noticable quality loss on challenge-sized images.
The actual image size (640 pixels by 480 pixels etc.) is limited by challenge rules to 640 pixels on the longest side. Most images are big enough to judge, although there have been one or two waaay too small. People generally don't have a problem doing the resize, so I won't say too much here. I usually scale my images to between 600 and 640 pixels on the long side.
I use The Gimp (//www.gimp.org) so I can't give any Photoshop-specific tips, but EddyG's workflow description (near the bottom of the that thread) gives very detailed instructions on how the wizard himself does it.
Getting a little more technical, one thing I found makes a huge difference in many cases is the chroma subsampling level of the JPEG compression. In the Gimp, the JPEG save dialog gives the option for "2x2,1x1,1x1" and "1x1,1x1,1x1". The 2x2 option allocates less space for the color part of the image data since the human eye is much more sensitive to changes in the luminance (brightness) part of the data than to the color part. But I found my images were much sharper usign the 1x1 option, at the expense of some file size increase. Simply reducing the quality setting from 98 to 97 or so would compensate, and the image would be much better in the end.
Don't let the last step in creating your entry ruin it: maintain as much quality as you can. Hope this helps someone, and I hope my eyes don't have to bear quite as many blocky patchy images next week. 8-) |
