b/w LAB workflows?

asamuel

Dear all

I am new to digital photography. and spanking to PS. Just installed CS2. Reading Mr. Margulis, reading about Raw, I want to hit it head on. Problem is I get confused with the work flows. Case in point;


Doing tutorials on DG. I like the B/W tutorial (has helped me), but it doesn't work if I mix it up with LAB, the color mixer disappears.

So a) stick with RGB for B/W?

or b) is their another workflow I've missed that makes BW in LAB?

just feel as though Im playing with a big twisted up ball of string or a rubix cube in the dark (with my hands cut off).

thank you.

p.s. dropped my camera today and knackered a lense so please be kind if my question is boring:uhoh

flyingdutchie

asamuel wrote:

Dear all

I am new to digital photography. and spanking to PS. Just installed CS2. Reading Mr. Margulis, reading about Raw, I want to hit it head on. Problem is I get confused with the work flows. Case in point;


Doing tutorials on DG. I like the B/W tutorial (has helped me), but it doesn't work if I mix it up with LAB, the color mixer disappears.

So a) stick with RGB for B/W?

or b) is their another workflow I've missed that makes BW in LAB?

just feel as though Im playing with a big twisted up ball of string or a rubix cube in the dark (with my hands cut off).

thank you.

p.s. dropped my camera today and knackered a lense so please be kind if my question is boring:uhoh

You can do B&W in L*a*b mode, but i won't recommend it.
Best is to use the Channel Mixer in RGB mode. Then you can choose how much of each channel (R and/or G and/or you'll use for each B&W pic.

But if you want to do B&W in LAB:
- Use Curves.
- Go to the a channel. Flatten the curve completely (make horizontal) halfway.
- Go to the b channel. Flatten the curve completely (make horizontal) halfway.
This way, all colors are mapped to 50% (grey).

If you flatten the channels but not halfway, you'll get a tint instead of pure B&W.

But again, i'd recommend using RGB for B&W.

DavidTO

flyingdutchie wrote:

You can do B&W in L*a*b mode, but i won't recommend it.
Best is to use the Channel Mixer in RGB mode. Then you can choose how much of each channel (R and/or G and/or you'll use for each B&W pic.

But if you want to do B&W in LAB:
- Use Curves.
- Go to the a channel. Flatten the curve completely (make horizontal) halfway.
- Go to the b channel. Flatten the curve completely (make horizontal) halfway.
This way, all colors are mapped to 50% (grey).

If you flatten the channels but not halfway, you'll get a tint instead of pure B&W.

But again, i'd recommend using RGB for B&W.

You don't need to go to all that trouble in LAB, just use the L channel and discard the A and B channels. That is, with L selected, go to Grayscale mode, and then you can go to LAB or RGB or whatever.

Most likely the best thing to do is to use LAB for the things that are its strengths. B/W can easily be done in RGB and I'm not sure that there is a real advantage to LAB here. There's the Gorman method (search the forum) that uses the L channel. But learning the Channel Mixer would be the first priority, I would think.

saurora

asamuel wrote:

just feel as though Im playing with a big twisted up ball of string or a rubix cube in the dark (with my hands cut off).

I can so relate to what you're going through! I am attempting to learn LAB, RAW and working in color and black and white. Whew!!! It's exhausting! I have no answers (yet) I'm not satisfied with my attempts at black and white. Good luck in your search for answers, I'll be paying close attention (as always!).

Richard

I routinely use LAB for my color work, but don't see any reason at all to use it for B&W conversion. RGB, channel mixer and curves seem to work fine for me.

Regards,

ginger_55

I work up a photo in the best way I know in color.................maybe LAB, maybe RGB, I do either one, sometimes one week, it is one, another week it is another................I don't know that much, but I do want a good looking photo in color when I go into black and white.

Then I am in RGB, I go to my printouts from Andy's instructions on how to do black and white and usually do it that way.

If you search for black and white+ Andy, you ought to come to that thread eventually. There was a long discussion on it.

Andy said to use channels, then there were other things you could do to boost the results, but channel mixer was the base.

That is with clicking on monochrome at the bottom of the channel mixer window. 50% red, 50% green, tweak if wanted..........remember the grain is in blue, but it can tweak well.

I have found that to be good enough. But I start out making a color print, I save that, then I go to black and white.

ginger

USAIR

Here's another way also.
Open your color photo
Then goto Image>Caculations
Then from the Caculations dialog box I choose red and blue channels and overlay for blending.
(blending modes and channel slections not in set in stone play with these settings)
Click OK then Image>Adjustments>Greyscale
Then dump into LAB
Then Curves and adjust lightness channel for best contrast.
Then sharpen the lightness channel.

This doesn't work for all photos but has some good results on some photos.
Also play with the Caculations settings some images it's best to choose red green channels...because of noise in the blue channel.

Fred