Finding a black point

christulk

Hi,

I did see a tute along a similar line, but can't find it now. From my limited understanding, when creating B&W it is a good idea to get a black point (jump in any time I start talking rubbish, and feel free to correct my termonology:D), so the way I have been doing it is using the levels layer. I get the eye dropper and put it on the darkest bit I can see.

Problem arises when there is no black in the picture (or is this a problem?)

So the long winded question, is there a way to get a true black without black being in the original??

Hope I'm not making too big of a fool out of myself!

:huh

DoctorIt

1) This is finishing school, for sure, I'll move it

2) I'm no expert, but I think the black point you define has be "in" your image.

3) here's DavidTO's excellent updated tute that covers this:
http://dgrin.smugmug.com/gallery/2292454/1

christulk

Thanks Doc!

Duffy Pratt

In RGB, anything with equal numbers is neutral. As a practical matter, anything below 5,5,5 will lose all detail and will appear as black on basically any display. There are displays that have a higher point where all shadows plug, possibly as high as 20,20,20, depending on the printer or monitor.

In B&W, since color balance is not an issue, anything can serve as a black point. All you have to do in B&W is decide where in the shadows you need to start seeing detail. Typically, you would pick the darkest significant object in the picture.

In color, you would pick the darkest significant neutral (or near neutral) object. People don't distinguish colors well in deep shadows, so getting the neutrality perfect is not that important. The danger with selecting something the camera sees as not neutral, and forcing it to neutrality, is that you could create a cast in the brighter areas of the picture.

I hope this helps.

Duffy

Richard

christulk wrote:

Hi,


Problem arises when there is no black in the picture (or is this a problem?)

So the long winded question, is there a way to get a true black without black being in the original??

You can set the black point to anything you like by dragging the little triangle icon on the bottom left in the levels histogram.

While it is generally good advice to set black and white points at the darkest and lightest significant portions of an image, it will lead you into a great deal of trouble if you insist on applying this to every single image. Some images are interesting precisely because of their high or low key, and forcing them to expand over the whole tonal range simply wrecks them.

Regards,

christulk

rsinmadrid wrote:

You can set the black point to anything you like by dragging the little triangle icon on the bottom left in the levels histogram.

While it is generally good advice to set black and white points at the darkest and lightest significant portions of an image, it will lead you into a great deal of trouble if you insist on applying this to every single image. Some images are interesting precisely because of their high or low key, and forcing them to expand over the whole tonal range simply wrecks them.

Regards,

Thanks for the tips. Appreciate it.