Posted by Kurt Rinne on January 3, 2010 at 5:21 PM
Happy New Year everyone!
Finally had time this past week to work on some of my photos from this past fall/winter. I was using acdsee and now have finally started using LR2. My question is this; once I'm done working on the photo, I export it as a jpeg (SRGB) 100% quality. When I compare the jpeg I just exported and the raw file they don’t look near the same. Most of the photos are a tad darker but this one I uploaded here is significantly darker in jpeg versus the raw file. Can anyone shed some light on why there is so much difference?
Thanks
Kurt
Posted by Kalin Wilson on January 3, 2010 at 7:49 PM
It's hard to say exactly what is affecting this image but there are two things that work against you when exporting to JPEG. The first is compression artifacts. You exported at 100% quality but there is still some processing and potential transformation that the JPEG algorithm will apply. This image seems to have broad expanses of similar colors which compress well, but complex color schemes lead to less compression and more artifacts.
The other issue you're dealing with is the differences between the ProPhoto color space, which is LR's default color space, and sRGB. sRGB is significantly smaller. So if you have colors that are rendering the way you like in ProPhoto but are outside the sRGB space, you'll get sometimes startling changes from the color space conversion. If you convert with perceptual rendering, all of the colors in the image will be compressed or shifted to maintain spatial relationships in the smaller space. This usually is OK if the spaces aren't too different, but sometimes the color shifts are really whacky. If you use relative rendering, then the out of gamut colors in the smaller space are clipped to colors that are on the spatial boundary. This will maintain most of the colors as you intended, but colors that were fine in ProPhoto but not available in sRGB will be changed - sometimes noticeably.
Most of the time I don't have much issue with converting from ProPhoto to sRGB, especially if you avoid hyper-saturated colors. Still, now and then you get surprises. Since LR doesn't have soft-proofing (yet), and I'd advise against changing LR's color space, your best bet in these situations is to bring the wacky image into PS in sRGB and adjust it to get what you want for web display.
Overall, I highly recommend doing your work in ProPhoto, especially if you print to any of the high quality pro photo printers out there on high quality luster paper (Ilford Gold Fiber Silk/Harmon FB Fiber). I routinely print straight from LR, with no soft proofing, by bumping the exposure 1/3 stop and printing through a custom paper profile. Today's printers have gamuts much better than sRGB and Adobe RGB and it won't be long before they match and exceed ProPhoto.
Kalin
Posted by John Mumaw on January 3, 2010 at 8:56 PM
I don't use LR, but using PS (which uses basically the same development engine) I never have any problems like this occurring when converting RAW to JPEG, or ProPhoto/Adobe RGB to sRGB. In fact, I rarely see much difference at all.
Where are you exporting the JPEG files to? A color managed app?
Posted by Kurt Rinne on January 3, 2010 at 11:09 PM
Thanks for the indepth reply Kalin. John I'm just choosing export and into a folder called keepers. I looked over most of what I've processed so far and it appears only this photo has the biggest difference. All the other keepers are only slight darker so I'll have to increase the exposure a little like Kalin suggested and see how it looks on a small print before printing large.
Discussion
3 repliesFinally had time this past week to work on some of my photos from this past fall/winter. I was using acdsee and now have finally started using LR2. My question is this; once I'm done working on the photo, I export it as a jpeg (SRGB) 100% quality. When I compare the jpeg I just exported and the raw file they don’t look near the same. Most of the photos are a tad darker but this one I uploaded here is significantly darker in jpeg versus the raw file. Can anyone shed some light on why there is so much difference?
Thanks
Kurt
The other issue you're dealing with is the differences between the ProPhoto color space, which is LR's default color space, and sRGB. sRGB is significantly smaller. So if you have colors that are rendering the way you like in ProPhoto but are outside the sRGB space, you'll get sometimes startling changes from the color space conversion. If you convert with perceptual rendering, all of the colors in the image will be compressed or shifted to maintain spatial relationships in the smaller space. This usually is OK if the spaces aren't too different, but sometimes the color shifts are really whacky. If you use relative rendering, then the out of gamut colors in the smaller space are clipped to colors that are on the spatial boundary. This will maintain most of the colors as you intended, but colors that were fine in ProPhoto but not available in sRGB will be changed - sometimes noticeably.
Most of the time I don't have much issue with converting from ProPhoto to sRGB, especially if you avoid hyper-saturated colors. Still, now and then you get surprises. Since LR doesn't have soft-proofing (yet), and I'd advise against changing LR's color space, your best bet in these situations is to bring the wacky image into PS in sRGB and adjust it to get what you want for web display.
Overall, I highly recommend doing your work in ProPhoto, especially if you print to any of the high quality pro photo printers out there on high quality luster paper (Ilford Gold Fiber Silk/Harmon FB Fiber). I routinely print straight from LR, with no soft proofing, by bumping the exposure 1/3 stop and printing through a custom paper profile. Today's printers have gamuts much better than sRGB and Adobe RGB and it won't be long before they match and exceed ProPhoto.
Kalin
Where are you exporting the JPEG files to? A color managed app?