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Fixing color in LAB
  
 
Peter Figen
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p.3 #1 · Fixing color in LAB


Even multiple trips to Lab and back have no visible effect on the image, but it's really a moot point as you really only go once, and it's almost always in 16 bpc, although there are plenty of stock images I work on that make that trip also. On those, which are always digital captures, compressed and with no process history, the skies often suffer regardless of what you do to them, but since we're not talking iStock here, it doesn't matter.


Mar 22, 2014 at 06:28 PM
ben egbert
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p.3 #2 · Fixing color in LAB


John Wheeler wrote:
Hi Ben
Adding a comment late to the party yet here are some minor thoughts to consider as I did not see them mentioned and you may already have it covered. Staying in 16 bit mode vs 8 bit mode has two advantages especially when jumping between color spaces or into LAB mode and back
- There is a subtle posterization that goes on as 8 bit has insufficient precision to prevent it
- Each time shifting back from LAB to RGB in 8 bit mode Photoshop throughs in a little bit of 1 bit noise dithering (to hide the banding) unless
...Show more

I never change to 8 bit until I convert to sRGB and save for web. So I am 16 bit the whole time. And typically, my workflow is like this.

Open with some prelim adjustments in ACR which pretty much sets the white and black point.

Run noise reduction on the sky.

Find the 50% grey point and mark it, possible also the black and white as well.

Go to LAB and run shadow highlights on L, then adjust AB and L in curves.

Go back to RGB and run Topaz photo pop, probably in luminance mode.

Run HSL/HSB and adjust hue saturation.

Run an action which goes back to LAB L, and run two USM, one fine grain and one high radius low amount and return to RGB.

Reset neutral grey if warranted and also fix the black point ..

Convert to 8 bit, sRGB downsize and save a jpg for web.



Mar 22, 2014 at 06:51 PM
ben egbert
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p.3 #3 · Fixing color in LAB


Peter Figen wrote:
Even multiple trips to Lab and back have no visible effect on the image, but it's really a moot point as you really only go once, and it's almost always in 16 bpc, although there are plenty of stock images I work on that make that trip also. On those, which are always digital captures, compressed and with no process history, the skies often suffer regardless of what you do to them, but since we're not talking iStock here, it doesn't matter.



I will never know, the only reason sRGB and 8 bit exists in my world is because web demands it. I even send 16 bit prophoto to my printer. And even though it is hard to see any difference between the higher and lower color spaces, its just easier for my workflow.

I save for web with actions. I have several for different purposes. For example 850 wide for landscape and 600 high for portrait in an FM folder. I sign and save 1024 wide for Facebook and Panoramio. I save full size for SmugMug. Each size has its own sharpening. I can make them at the click of mouse and so if I redo the image for some reason I just resave.



Mar 22, 2014 at 06:58 PM
John Wheeler
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p.3 #4 · Fixing color in LAB


Thanks for sharing your workflow Ben including an interesting dual round trip to Lab. Much appreciated and something for me to consider. As I indicated in my prior post the issues to which I referred were only for 8 bit mode. There are ways to mitigate those issues yet since you are staying in 16 bit mode until the last stage it is a moot point for this thread. Thanks again.


Mar 24, 2014 at 05:04 AM
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