When I post my herons, it was brought out that my jpgs looked a little oversharpened. Did a little research and Arthur Morris had a good way to convert. Posted a before and after.
Thanks Bill. I have his digital basics guide.
Convert to sRGB
Image size at 96 ppi. Click off the resample box
File/Automate/Fit to image 800 in width and height box
Unsharp Mask: 350/0.2/0
File/Save for web
200kb in the Optimize for file size
Question...for web posts, is there any advantage to going above 72ppi. I've read articles saying there is not, but I've also read recommendations similar to what Dan posted. Anyone know the "correct" answer?
Good question. I know you can get a headache trying to figure out the best way to do it!
Posted by Kalin Wilson on April 4, 2011 at 9:32 PM
The ppi is actually going to be determined by the monitor it is viewed on. The size of the displayed image will vary depending on the pixel density (ppi) of the monitor. What you set it to when resizing is not very important unless you need to target a particular output device. When you print it is much more important to ensure that you get the image at the size you want with enough image information for the printer to render a good image. Most of the time for web posts you are targeting an image dimension (720px on the long side) vice a size (8 inches), so the ppi setting is irrelevant.
Most monitors these days display 85ppi or better depending on size and resolution. 72ppi was driven by 800x600 displays. My 26" NEC 2690wUXI at 1920x1200 displays 87pp, so you 720x80 image displays at 720/87=8.27" 480/87=5.5" on my monitor. The image size on your monitor may be different. Check out this site to calculate your monitor pixel density.
"Most of the time for web posts you are targeting an image dimension (720px on the long side) vice a size (8 inches), so the ppi setting is irrelevant."
That's it in a nutshell. All you have to pay attention to is the image dimension on the long side.
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With all that sky, you won't see much (if any) difference between 200kb and 300kb sizes, Dan. For images with lots of detail throughout, an extra 100kb can make a relatively big difference!
Posted by Dan Walters on April 4, 2011 at 10:15 PM
Thanks for the info!
Posted by Tom Stermitz on April 4, 2011 at 10:57 PM
For a JPG on a web page, the dpi doesn't matter. That is, on a web page, the image is displayed in pixels, not inches, so only the number of pixels matters. For web display, you have to resample your image to fit within the page (the 800 pixels in the fit-to-image instruction). A lot of modern monitors display 96 dpi, so choosing that number lets you see how wide your picture will look; nothing else. Traditionally, monitors had a coarser resolution, which is where the 72 dpi comes from.
These instructions seem to be slightly ambiguous, and I'm not sure this is the right sequence. (Maybe there is something about it I don't understand.
Image size at 96 ppi. Click off the resample box
File/Automate/Fit to image 800 in width and height box
Unsharp Mask: 350/0.2/0
This unsharp mask gives you a local contrast enhancement (350%/0.2 pixels). Normally, you apply local unsharp mask at the end once you have chosen your output resolution. I don't quite understand why they're asking you to do the unsharp mask on the full-resolution image, and then sample at the end. (Usually, you do the opposite, resample, then unsharp mask.) In this case, applying a very localized, 0.2 pix sharpening to a large resolution image would be swamped when you resample down to 800 pixels wide.
Beyond that, there is an additional ambiguity in the instructions. We don't know what resolution the bird is at when you apply the unsharp. It could be 16 mpix ( 4672 x 3104) or a 3 mpix (2144 x 1424) crop from the center of the image.
Localized contrast enhancement really brings out the details on feathers or rocks. Sometimes you also apply a much broader unsharp mask, say 40%/150 pixels/ 0 threshold, which gives you more of an edge enhancement and wide area contrast enhancement. You can see that you might have to adjust the 150 pixels depending on resolution, but in this case, resampling wouldn't make the enhancement disappear, so you would be able to apply it prior to resampling.
Posted by Dan Walters on April 4, 2011 at 11:27 PM
Dan- thanks for looking into this subject as I have experienced the same situation. I have noticed some others that have posted birds lately with the same problem. Maybe this will help all of us.
Posted by Brian Jackson on April 5, 2011 at 10:01 AM
I haven't found anything that works as good as the "Marc Sharpen" method for web sharpening. Not sure who created it but Marc Adamus is the one that posted "howto" about it.
Posted by Tom Stermitz on April 5, 2011 at 2:45 PM
Did you see why your first photo was described as over-sharpened?
Note the thin line of white fringing in the sky right around the bird. A good indicator of too sharp is when this line becomes visible. It's easy to back off until it disappears.
Discussion
17 repliesThanks for any additional tips.
Convert to sRGB
Image size at 96 ppi. Click off the resample box
File/Automate/Fit to image 800 in width and height box
Unsharp Mask: 350/0.2/0
File/Save for web
200kb in the Optimize for file size
Thanks for any other suggestions!
You know that we can post images at 300kb now, right?
Most monitors these days display 85ppi or better depending on size and resolution. 72ppi was driven by 800x600 displays. My 26" NEC 2690wUXI at 1920x1200 displays 87pp, so you 720x80 image displays at 720/87=8.27" 480/87=5.5" on my monitor. The image size on your monitor may be different. Check out this site to calculate your monitor pixel density.
Hope this helps a little.
_____________________________________________________________________
With all that sky, you won't see much (if any) difference between 200kb and 300kb sizes, Dan. For images with lots of detail throughout, an extra 100kb can make a relatively big difference!
These instructions seem to be slightly ambiguous, and I'm not sure this is the right sequence. (Maybe there is something about it I don't understand.
This unsharp mask gives you a local contrast enhancement (350%/0.2 pixels). Normally, you apply local unsharp mask at the end once you have chosen your output resolution. I don't quite understand why they're asking you to do the unsharp mask on the full-resolution image, and then sample at the end. (Usually, you do the opposite, resample, then unsharp mask.) In this case, applying a very localized, 0.2 pix sharpening to a large resolution image would be swamped when you resample down to 800 pixels wide.
Beyond that, there is an additional ambiguity in the instructions. We don't know what resolution the bird is at when you apply the unsharp. It could be 16 mpix ( 4672 x 3104) or a 3 mpix (2144 x 1424) crop from the center of the image.
Localized contrast enhancement really brings out the details on feathers or rocks. Sometimes you also apply a much broader unsharp mask, say 40%/150 pixels/ 0 threshold, which gives you more of an edge enhancement and wide area contrast enhancement. You can see that you might have to adjust the 150 pixels depending on resolution, but in this case, resampling wouldn't make the enhancement disappear, so you would be able to apply it prior to resampling.
Note the thin line of white fringing in the sky right around the bird. A good indicator of too sharp is when this line becomes visible. It's easy to back off until it disappears.