Luminous Landscape Forum
Raw & Post Processing, Printing => Digital Image Processing => Topic started by: bobrobert on February 24, 2006, 07:01:23 am
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If some one took an image say at a file size 6 MB ( my fuji 7000 jpg size fine setting 267 ppi at 10 x 8 ) and saved it for web reducing it to 100kb, would there be a difference in quality if I had taken it at the lowest jpg setting in camera ( 1MB )and saved it at the same size In other words is the jpeg compression in camera better than Photoshop or does it matter? TIA
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If I understand "Save for Web" correctly, the process optimizes the photograph for web display. This would include converting to the sRGB color space too.
I tend to always shoot at the highest quality possible (in my case, RAW). This allows me to have the most options with my photos. If there is a photo I want to add to my website, I follow this workflow:
1. Convert from RAW to a 16 bit image.
2. Do any necessary processing and cropping.
3. Convert to 8 bit mode.
4. Adjust image size to 72 dpi and pixel dimensions to desired size.
5. Save for web
Depending on quality level chosen and picture detail, I end up with a photo that is usually somewhere between 15K nd 40K. This gives me a photo that will display well on the screen but will not print well at all, preventing someone from hijacking your work and printing copies for themselves. It also allows faster page loading.
If I know that I am shooting a family event like a birthday party for the kids, then I will shoot in JPG mode, usually small and fine quality. This lets me make a 4x6 print if someone wants one. I still prepare the images for the web by converting to 72 dpi and saving for web. Again, pages with a lot of images will load quickly.
As always, the screen shot will not show the detail of a print.
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I use the same sequence as Rich, and I'm happy with the results. You are likely to find a sharp split among folks preparing images for web display. Some hate the Save for Web feature in Photoshop, while others aren't bothered. Results with either are so close that I use Save for Web as a matter of convenience.
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In addition to what Rich and Hank said above, "Save to Web" also strip metadata from the file and set resolution to 72dpi (no resampling). I mainly use "Save to Web" to see how the JPEG compression affects image quality and to reach a certain file size (ex: 150kB).
One word of caution, "Save to Web" does not convert to sRGB, it keeps the original profile.
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One word of caution, "Save to Web" does not convert to sRGB, it keeps the original profile.
That's not entirely accurate.
It's user configurable whether you supply profile information (and what that is).
I'm mostly using regular save-as to avoid these and other problems. I used to like the preview, but it's generally just adding another time consuming step to the conversion process.
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Rich's sequence is fine except it may be safer to reverse steps 4 and 5 so the resampling is done in high bit mode.