Clipping and Auto Color in Levels

[sc21]

I'm copying some old b/w pictures using a 10D and macro lens, and I

got a question about how to get the best tonal range and color when

working in CS.

 

I open up the RAW file, set it to 16 bit, click the eyedropper on

something white to neutralize the color cast, then adjust the

exposure and shadows to just before I see tiny dots showing clipping

within the picture.

 

Then I hit okay, crop out everything around the picture, and use a

Levels adjustment layer to fine-tune the tone.

 

Now, when I adjust the clipping here, do I stop when I first see

clipping, as with a bunch of yellow in the shadows, or do I clip

through the yellow and red until I see actual black patches?

 

Or do I go through each channel in Levels and adjust them

individually, so that when I later drag the slider in RGB, it goes

straight to white?

 

Or do I simply go to Levels-Options for the Auto Color Correction,

which is the same thing as the last step, only with more choices?

If so, where do I set the white and black clipping points?

 

It's great to be learning new processes, but I'm still fumbling

about, and your experience would be helpful.

[Ed_Ingold]

You can use Levels to set the RGB white and black points (Auto Level) or use Levels/Options to set the output by RGB, individual colors or the darkest color. Rather than use Auto Level, I usually go to the Options panel and see what looks best. Optimizing each color usually results on an oversaturated image, often with a color cast. At best, it brings you close enough to center for fine adjustment with Curves.

 

In the Options panel, you can also set the white and black threshhold percentage. It defaults to 0.5%, which I find excessive. I reset the default value to 0.1% (or less). The Levels Default setting is the same one used by Image/Adjustment/Auto Level.

[Ed_Ingold]

I missed the "copying B&W" part.

 

Don't waste time neutralizing the RGB color. Simply desaturate or change to Grey Scale mode to discard color information, and adjust using Levels. If you wish to emulate a toned BW print, change back to RGB mode and use the hue/saturation mode to add tonality.

 

If you are copying a color print and wish to convert to BW, use Channel Mixer (or a plugin) to emulate BW spectral response before converting to Grey Scale.

[sc21]

Thanks, Edward - never thought of the greyscale.

 

And about Auto Color Correction, you're right about the defaults. Both Eissmann (?Restoration and Retouching?) and Blatner/Fraser (?Real World CS?) say the default on this tool is too much, but Eissmann doesn?t recommend a point (she uses .02 in one and .2 in another), and Blatner/Fraser set it at .00 for black and .01 for white, which on one picture I tried actually brightened the shadows from 96% to 94% (when color sampler set to greyscale).

 

Dang, this is complicated stuff.