Pekka - Tell me how to sharpen the luminance channel only !!

[msbaek71]

Pekka !!

First of all, I'm a novice for PS so would you explain more detail !!

In your workflow you said that

Use several actions to resize image to gallery sizes, sharpen with USM (alpha channel, A:25% R:0.6 T:0)

I found that it means followings:
convert to Lab mode and sharpen the LUMINANCE channel only

I cann't fully understand both of the aboves...

Would you let me know step by step how to do these !!
Thanks in advance !!

[sasc]

well im not Pekka, but you go to the image menu and pick mode. Then Lab. Then you go to sharpen the luminence channel and convert back to RGB

[Peter Gregg]

I know how to do it in PS6.

First open a picture, then click on the word IMAGE then MODE then click on LAB COLOR. This will put you in the LAB COLOR mode.

You need to have the CHANNELS pallette open in the bottem right of your screen. Do this by clicking on WINDOWS and then SHOW CHANNELS. A little pallette will open in the bottom right of your screen. Click on LIGHTNESS and the photo will turn black and white. If you do not see the word LIGHTNESS then click the CHANNELS tab in that little window.

From there you do your Unsharpen mask and it will apply only to the lightness channel.

After you are done, go back to IMAGE, MODE, and then RGB COLOR. This will put it back into the normal color mode and from there you can move on to do other things with the picture.

Pete

[msbaek71]

Thanks sasc and Peter !!

I can fully understand what you guys said...
It's very helpful to me...
Hope you can have good pictures with D30 !!
Regards...

[gerry]

with regard to lab color and the lightness channel, this is the only way to get a really good rgb to b/w conversion.

Try converting in PS to grayscale from rgb.

Take the same photo before the conversion and convert from rgb to lab, then go to channels and select the lightness channel, then drop out the colors by converting to grayscale.

Compare.

If you have not done this before, you'll be amazed at the difference.

[KennyC]

The quickest way to sharpen the luminance channel only is to sharpen normally and then Fade at 100% to Luminance.