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Photography and Photoshop Tutorials
 
HDR Luminance Masking
Using a simple Low Pass Luminance Mask to create a HDR image
 

HDR imaging using a simple LPF type luminance mask.

Luminance masks are a powerful channel chop that you can use to create HDR images from two bracketed frames.

With HDR Luminance Masked Shadows

With HDR Luminance Masked Shadows

Without HDR Luminance Masked Shadows

Loading the composite channel’s selection in the Channels window creates a luminance mask. This causes all values in the image above middle gray to become selected as a continuous tone image rather then a regional selection. This simple mask splits the tonal range in the middle allowing you to take the highlights from one image and the shadows from another and have a great deal of logical control over the blending. Because of the continuous tone nature of the mask there are no masking lines. The highlight mask is then inverted to create a tonal Low Pass Filter with a bandwidth of 128 and a band center of 64. The main difference between this and a standard LPF response is that there is only roll off on the high end of the scale creating a soft transition between the two exposures. There is no roll off on the low end.

This can often produce a superior result to using Photomatix or other HDR compositors as you have a Photoshop workflow which has familiar controls and does not mangle the colors and basic tonalities.  Photomatix can be good but has its foibles. I have been working on HDR methods for use in the context of Photoshop. I have yet to hear a report of the Photoshop compositor functioning so that is not part of any of my solutions.

...

I have a simple two layer example that demonstrates the concept. The frames in this case are 3 stops apart. One frame exposed for the sky and one that is three stops over, N and N+3. The exposure is changed via the shutter speed to prevent differences in depth of field. The example has the luminance mask on the shadows frame. The Shadows frame is very light but since all values above 128 are masked (discarded) it can be considered to be ETR’ed or Exposed To The Right. This allowed me to drop the brightness significantly and gain better middle tone separations.

I burned the right side of the sky some in the RAW converter on the way in to Photoshop. When I had the layers imported into Photoshop I knocked out some of the darker sky in the Shadows layer with a paint brush. This allowed me to take the whole sky from the Highlights layer.

Here is the Step by Step:

  1. Select files in Bridge
  2. Adjust in the RAW converter and hit Done button
  3. In Bridge select files and use Tools->Photoshop->Load Files Into Photoshop Layers
  4. Put the lighter layer on top and name it Shadows with the darker layer below it named Highlights.
  5. In Photoshop I selected both layers and used Edit->Auto Align Layers - Collage
  6. Select the lighter (Shadows) layer, go to the channels window and hit the Load Channel as Selection Button (dotted circle) at the bottom of the window.
  7. This selected all values above 128
  8. Invert the selection, Selection->Inverse
  9. In the layers window select the Shadows frame
  10. Press the Add Vector Mask (dot in dark rectangle) button at the bottom of the Layers window.
  11. A continuous tone transparency mask will appear on your shadows layer that will expose the values below 128.
  12. You have now created a HDR image using a luminance mask.

Once you have reached this point you are ready to adjust the balance. Use the Clip to Layer button to add a levels layer to the shadow layer and adjust. You can also achieve a similar effect by using the transparency mask from the Shadows layer on a Levels layer. After some levels adjustment of the shadows you can mellow the effect by using the Layer Blending dialog for the Shadows layer and setting the Blend Mode to Normal and the Opacity to less then 100%.

My goal in dealing with excessive contrast is to make an image where it is not obvious that the image is HDR other then the fact that a skilled photographer will recognize that it is a high contrast scene with full detail in shadows and highlights.

Here is a zip file with a small layered example file:

http://www.cookseytalbottgallery.com/shared/HDR-LPF-Luminance-Masking.zip

In the example I have not done any of the burning and dodging that I would usually do to keep it simple. Consider this example a first step in creating the beginning image ready to have the normal work done to accentuate the separations and colors.

Have Fun!!!

Cooksey
cooksey@cookseytalbottgallery.com
http://www.cookseytalbottgallery.com/
http://www.facebook.com/pages/Cooksey-Talbott-Photography/397013872387
http://www.etsy.com/shop/cookseytalbott

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Contents
 
Profile Extents Test Target
 
Precisely target the high and low values in your prints...

Day for Night Photography
 
Reality is not always exactly that...

Luminance Masking for Contrast Control
 
Using luminance masks on adjustment layers to control specific tonal ranges in your image.

HDR Luminance Masking
 
Using a simple Low Pass Luminance Mask to create a HDR image

HDR Burning and Dodging
 
Use a HDR photo stack and transparency masks to get excellent results with this burning and dodging like method.

Profiling Your Digital Camera
 
Free utility to build and edit profiles from Adobe Labs

Using the X-Rite Color Checker to Create Camera Profiles
 
This really optimizes the color output of your camera!

Using the Photoshop History Palette and Snapshots Effectively...
 
Or, whos your friend baby...

Using the Photoshop Threshold adjustment layer to evaluate image density and contrast for digital printing.
 
This is an easy method to target a files density for printing. It requires a basic knowledge of Photoshop adjustment layers.

Building Photographic Websites
 
I make websites for artists and find that most folks need some sage advice on the process...

I got a new film camera, the Gaoersi 617
 
Direct from Hong Kong

Camera Settings for Digital Photography
 
How to set your digital camera to get the best images possible

Filters for Color Digital and Film Photography
 
Use these filters to improve the color and rendition of your photographs.

Basic Daylight Exposure (BDE) Calculation
 
For outdoor photography the light meter is not always your friend...

Film Speed Table
 
A table of film speeds, E.I.'s in 1/3 stop increments.

Bellows Extension Calculator
 
Online bellows extension factor and exposure compensation calculator and printable exposure compensation scale

Spotting Flecks on Ink Jet Prints
 
Using Marshalls retouching dyes to remove those occasional flecks

Stretching Canvas Photographs
 
How to stretch photographs printed on canvas with inkjet printers.

 

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Web Site by Cooksey-Talbott Studio

Fine art photography of California by master nature photographer Cooksey-Talbott. Hundreds of beautiful photographs are displayed for sale online as raw or ready to hang images.

Cooksey-Talbott Gallery is an online gallery of nature photographs. The collection includes pictures of the High Sierra, Ansel Adams Wilderness, Yosemite, Trinity Alps, Sonora Pass, Santa Barbara Hills, East Bay Hills and Garin Park as well as hundreds of different waterfalls. Legacy images are from medium and large format film taken with the Mamiya RB-67 and a variety of 4x5 view cameras. Some of the more recent work is shot with a Nikon D200, Canon 5D Mark II and the Sony A7r.

We offer archival quality prints in a wide range of sizes and media. We print on a heavy art papers and canvas using a Canon iPF8300 44 inch 12 color printer with pigmented inks. Our images are first party prints made directly by the artist. Prints are signed and numbered and include a Certificate of Authenticity.

Ralph Cooksey-Talbott Thomas has been working as a photographer since 1972 when he moved to California from Michigan. During the 1970’s he studied under Ansel Adams in Yosemite. Ansel published one of his photographs in the portfolio section of his book "Polaroid Land Photography" Ansel and Orah Moore, another of Ansel’s students, suggested that he shorten his name to Cooksey-Talbott, and that is the name he has worked under since. Cooksey also studied at the San Francisco Art Institute and the San Francisco Academy of Art. He has lectured in photography at the U.C. Berkeley Extension, Studio One in Oakland and Santa Barbara City College. Cooksey is currently working as a photographer and facilitating S3-Photowalk.com which is a monthly photo walk that meets up in Niles California.