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metroshane
03-09-2004, 06:49 PM
Can someone please explain masks (especially the unsharp mask I hear so much about). I'm pretty smart, just ignorant...so get as technical as you want.
voodoocat
03-09-2004, 06:59 PM
Hey Shane, I was just planning on adding unsharp mask to the tips section this evening. The best way to do it is to switch to lab mode (image > mode > lab) then on the channels tab select lightness and apply the unsharp mask. For prints I use between 100-150%. Then you can switch back to RGB mode.
Osmer_Toby
03-09-2004, 07:58 PM
is it really necessary to go to lab? i sharpen in rgb; is there some advantage to converting and sharpening just the lightness channel of luminosity?
also, unsharp mask is kinda misleading- it's found in the filter section...
voodoocat
03-09-2004, 10:08 PM
is it really necessary to go to lab? i sharpen in rgb; is there some advantage to converting and sharpening just the lightness channel of luminosity?
also, unsharp mask is kinda misleading- it's found in the filter section...
Yes, it yields better results. That way you aren't messing with the color information in the image.
gonzo
03-09-2004, 10:46 PM
Yes, it yields better results. That way you aren't messing with the color information in the image.

voodoo, we humbly bow before thy great wisdom. I've learned something new again!
voodoocat
03-09-2004, 10:58 PM
Ok, the tutorial is complete. You can see the difference between sharpening in Lab vs RGB mode :D
gonzo
03-10-2004, 04:28 AM
voo, thats an excellent tutorial.. but the final results i am not sure why you blew up the final comparison, i am have a hard time distinguish the difference between the two :scratch:

however, when i went and tried the lab thingy on one of my photos and the results were amazin! Thats one of the best darn tips i've learned in while!
voodoocat
03-10-2004, 08:41 AM
I blew it up because you can see the difference in the noise on the samples. The one done in RGB mode has a lot of stray color pixels, the one done in Lab mode does not.
Digital Matt
03-15-2004, 12:19 AM
Thanks for the lab tip. Here's another. You can use the unsharp mask to add contrast to a photo as well. Using a setting like 20%, 50, 0 will add a subtle contrast boost to your image, and then you can run your normal unsharp mask setting afterwards. I normally use 500%, 0.2, 0, or 300%, 0.3, 0.

I got this tip from the Luminous Landscape. Here's a link to the article.

http://www.luminous-landscape.com/tutorials/contrast-enhancement.shtml