Thorninger.com

About, Bird photography, Landscape and Seascape, Macro and extreme macro photography, Surreal trick photography

 

 

About working with channels selections in Photoshop

When You are combining the ability to create selection masks with the ability to create Action and Actions Sets in Photoshop, you get a powerful tool for working with tone mapping in every picture.

In the Channels Panel it is possible to create selection masks and save the selections as Alpha Channels.

One of the benefits of using these types of masks is, that when targeting tonal ranges, the mask itself is self-feathering, helping to avoid problems with blending and hard transitions.

When you select part of an image, the area that is not selected is masked, or protected from editing. So, when you create a mask, you isolate and protect areas of an image, as you apply effects to the rest of the image.

Masks and channels are grayscale images, so you can edit them like any other image with painting tools, editing tools and filters. Areas painted black on a mask are protected, and areas painted white are editable.

Once stored as an alpha channel, you can reload the selection at any time. You can inverse a selection and save it as a new Alpha Channel. You can subtract a mask from an existing selection and save it as a new Alpha Channel.

The Channels Panel

The Channels panel with the the Channels panels toolbox

Channels panel menu

Control Key Shortcuts when working with Channels

Windows


Mac OS

Ctrl + a Select all Command + a
Ctrl + d Clear selection Command + d
Alt – click the New Channel button Create an alpha channel mask and set options Option – click the New Channel button
Shift + Ctrl + Alt and select the channel Decrease pixels selectet Shift + Command + Option and select the channel
Ctrl + Alt and select channel Subtract the channels selection from existing selection Command + Option and select channel
Ctrl and select channel Opens saved channels selection Command and select channel

A Zone Chart are usefull, when creating Luminosity Masks.


Zone 0 are total black, zone 1 are black with no details, zone 2 are black with details, Zone 5 are middle gray like the gray chart, Zone 8 are white where details can be seen, zone 9 are white without texture, zone 10 are burn out white.
The dynamic range of the human eye, from the darkest we can perceive, to the brightest are around 20 EV(stops). In a single shot digitale cameras kan record around 9 EV in JPG. The best monitors can show around 9 EV.
If You take 3 photos with 2 stops betveen You can capture 13 EV.
But You can only show max 9 EV, and must compres the 13 EV to 9 EV.
The tecnic are HDR and tone mapping.


I have createt an Action set with luminosity masks on basis of the zone system. The luminosity masks corespond to the zones: 0-1, 2-3, 4, 4-6, 6, 6-7, 7-8, 8-9, 9-10 and 10.

I have made a step by step tutorial, about how I did it:


Do you have some questions or suggestions for a better description, please send an email.



 

 

 

 

About, Bird photography, Landscape and Seascape, Macro and extreme macro photography, Surreal trick photography