Posted by Reed Bowman on March 2, 2009 at 10:25 AM
Hi... New to NP and I noticed some color banding in my .jpgs that I processed to upload that were not present in the originals. I'm exposting to sRGB color space, resizing the short edge to about 1200 pixels and setting the quality at about 40-45. I also sharpen for screen. Anybody have recommendations for exporting .NEf files from Lightroom (I'm using 2.2) as .jpgs suitable for uploading to NP? I assume I have to keep them under 200kb.
Thanks
Reed
Posted by David Sparks on March 2, 2009 at 12:35 PM
Reed:
I've set up two export presets: one for 720 pixels for longest side and one for 1200 pixels. In the preset I rename the files with {filename}-720 or {filename}-1200. I specify sRGB as the format of the exported images. I have not found a specific quality that insures that the 720 pixel images will be less than the 200kb max for 720 pixel images or 500kb max for 1200 pixel shots. The actual size of the downloaded file seems to depend on the amount of detail in the image. I can change file size by trial-and-error adjustments with quality, but usually I just dump them into a folder where I store possible candidates for posting. When I decide to post a specific image I usually load it into Photoshop and use the Save for Web feature for controlling actual file size.
The banding you are seeing could be an artifact from your jpg compression. 40-45 quality is pretty low, and at this quality you should expect pixelation and banding in certain low detail areas of your image. I'd recommend raising the jpg quality, and if you need to get under a size limit compensate by lowering the image size.
Posted by Scott Reeves on March 2, 2009 at 3:27 PM
EDIT: I mentioned I was a bit delirious. Case in point - it appears you are exporting straight from LR to jpg. I've never done that, but would not be surprised if that's where the banding is incurred.
ORIGINAL: This may or may not help, as I am somewhat delirious fighting a cold... Reed, you said you were shooting RAW, which I assume is 12 bit, which means you have 4K bit depth. This should be a huge advantage to avoid banding when processing in LR, as compared to jpg originals (256 bit depth), but not as good as 14 bit encoding (16K bit depth). So if you process original sizes in LR and export to PS/CS (which effectively becomes a tiff) and then process in PS at the original size or size larger than the final web version, it should help to avoid banding. The last step should be to size and save for the web. Simply save at the highest quality available to meet the max file size requirment for NPN. ... It should also be noted that banding typically occurs with significant curve or sat adjustments. If possible, try to get the correct capture in camera to avoid major adjustments which result in banding.
thanks. I set up the same presets and used the save to web feature of PS3 and I'm much happier with the results. I was able to set quality at 100 in Lightroom and then set the exact file size with the highest quality in PS3... works great... know I'm going to be learning tons on NP. Although I shot film for years, digital is all new for me.
Just as an FYI, according to the submissions guidelines "Images must be no larger than 640 pixels overall on the longest side (250 pixels for photos to be included on the Photographer Profile page). Images uploaded to our server that are larger than 640 pixels will be automatically downsized. Links to images hosted on other sites that are larger than 640 pixels will be rejected". I don't know if you are noticing the color banding prior to downloading or after but if it is after, it might be from double downsizing.
The 640 pixel limit is (was?) for the PhotoPortfolios.net images only. The limit on the regular forums is 720 pixels on the long side and 1200 pixels for the Larger File link. The 720 pixel image must be posted, and be under 200 kB. The 1200 pixel image is optional, and must be under 500 kB. It will show up as a link just under the 720 pixel image.
That being said, are you trying to save the 1200 pixel image at under 200 kB? That's probably not a great idea. Still saving at 40-45% isn't unheard of. It's more likely that you are making fairly large adjustments to the NEF/TIFF, and when converting to 8-bit JPG, posterization is resulting. Perhaps posting examples with the steps you took could help?
Discussion
6 repliesThanks
Reed
I've set up two export presets: one for 720 pixels for longest side and one for 1200 pixels. In the preset I rename the files with {filename}-720 or {filename}-1200. I specify sRGB as the format of the exported images. I have not found a specific quality that insures that the 720 pixel images will be less than the 200kb max for 720 pixel images or 500kb max for 1200 pixel shots. The actual size of the downloaded file seems to depend on the amount of detail in the image. I can change file size by trial-and-error adjustments with quality, but usually I just dump them into a folder where I store possible candidates for posting. When I decide to post a specific image I usually load it into Photoshop and use the Save for Web feature for controlling actual file size.
ORIGINAL: This may or may not help, as I am somewhat delirious fighting a cold... Reed, you said you were shooting RAW, which I assume is 12 bit, which means you have 4K bit depth. This should be a huge advantage to avoid banding when processing in LR, as compared to jpg originals (256 bit depth), but not as good as 14 bit encoding (16K bit depth). So if you process original sizes in LR and export to PS/CS (which effectively becomes a tiff) and then process in PS at the original size or size larger than the final web version, it should help to avoid banding. The last step should be to size and save for the web. Simply save at the highest quality available to meet the max file size requirment for NPN. ... It should also be noted that banding typically occurs with significant curve or sat adjustments. If possible, try to get the correct capture in camera to avoid major adjustments which result in banding.
thanks. I set up the same presets and used the save to web feature of PS3 and I'm much happier with the results. I was able to set quality at 100 in Lightroom and then set the exact file size with the highest quality in PS3... works great... know I'm going to be learning tons on NP. Although I shot film for years, digital is all new for me.
Just as an FYI, according to the submissions guidelines "Images must be no larger than 640 pixels overall on the longest side (250 pixels for photos to be included on the Photographer Profile page). Images uploaded to our server that are larger than 640 pixels will be automatically downsized. Links to images hosted on other sites that are larger than 640 pixels will be rejected". I don't know if you are noticing the color banding prior to downloading or after but if it is after, it might be from double downsizing.
The 640 pixel limit is (was?) for the PhotoPortfolios.net images only. The limit on the regular forums is 720 pixels on the long side and 1200 pixels for the Larger File link. The 720 pixel image must be posted, and be under 200 kB. The 1200 pixel image is optional, and must be under 500 kB. It will show up as a link just under the 720 pixel image.
That being said, are you trying to save the 1200 pixel image at under 200 kB? That's probably not a great idea. Still saving at 40-45% isn't unheard of. It's more likely that you are making fairly large adjustments to the NEF/TIFF, and when converting to 8-bit JPG, posterization is resulting. Perhaps posting examples with the steps you took could help?