Wednesday, May 26, 2010

Tutorial - Extracting Image with Blurred Edges and Replacing Background

This article describes how to extract objects that have some movement on the edges and then replace background and not have the image appear as a cutout and placed on a new background.

The main feature is selecting the outline of the ducks with magic wand and then applying a white colour stroke to create a 10 pixel outline. This will be used later to re-introduce some blur around the duck wings to make this more realistic and not quite the cut-out effect.

The black winter pool cover was still on in the backyard pool and with some recent rain, two Mallard ducks thought this was an interesting place to visit and feed on some of the algae growing in the warm stagnant water.

There is a cedar hedge all around the yard so with this privacy, they have landed many times over the years. This always gives me a great opportunity to step out and photograph at close range.  They are not too afraid and normally I can get to within 15 feet of them. The problem is actually getting them to fly away for those interesting winged shots without scarring them so much that they won't come back.

I noticed that the male duck would bob its head up and down as I would approach.  I mimicked this bobbing motion and within a few moments this caused them to fly away.

A soft sky background would make the Mallards stand out nicely. Just having installed Photoshop CS5, I thought this would be a good opportunity to try the new refined edge when creating masks.
I will explain my approach by using the layers' palette, as the discussion's focal point, going from the bottom to top.

In the panel below (number 1-6 going left-right and top – bottom ) the image top right (#1) is the original capture as they flew away from the pool. The ducks are reasonably crisp but there is way too much clutter around and the female duck is almost hidden in the tree branches.

Original Duck Image – the original image captured by camera is in panel #1

Sky background
– suitable sky selected from files panel #4. It was flipped horizontally so that the diagonal of cloud sky edge matched the linear motion of ducks going from bottom right to top left.

DSC6177 Smart RAW copy for color extraction
– Copy of RAW file inserted as a smart layer. This version allowed me to darken the sky (more blue – panel #2) to help with refine edge to better detect change between white feathers and sky. Once mask refined, it was saved as a channel for each of the ducks

Mask for larger Duck -  The channel mask for large duck loaded and applied to copy of original duck image.

Mask for small Duck – The channel mask for small duck loaded and applied to copy of original duck image.

Mid Gre
y – A mid tone grey fill layer created to assist with viewing and refining edges against background. Some of the bird edges are white and with an almost white sky it is harder to detect edge.
Whenever using automated tools, I find it's always better to assist with the task by either changing contrast or colours to make the extract easier. Here I used colour changes in RAW files. Sometimes I may even go to over-saturation when dealing with earth tones.

Merge Ducks Master
  -  both masked images for ducks loaded as a new layer. See panel #3 but with no grey background.

Stroke Mask for edge of Ducks -  The Merge Ducks Master Copy and Mid grey selected and magic wand used on grey background. This gives me a marching ants selection around ducks. This section was then stroked (Edit-Stroke with a 10 pixel, white, center) setting creating panel #5.

B&W Luminosity – a Copy of Merge Ducks Master copied and set to luminosity mode.
B&W Adjustment color effect - A  B&W adjustment layer was applied to this B&W Luminosity layer and adjusted for desired colour effects. The Blue, cyan and yellow  increased to lighten colour. See panel #8.

High Pass
- Copy of Merge Ducks Master and a high pass filter applied and layer set to overlay mode. See panel #7.

Blurred Winged Edges – Original layer copied and Gaussian blur applied (3.5px). The Stroke Mask for edge of Ducks was applied as a mask and the main body duck edges were painted black with 50% opacity to reduce blur effect on these parts but have the most blur on the moving wings. Panel /6 is mask.

This stroke mask could also be used to reduce colour fringing around the edges by applying a Hue/Sat adjustment layer and reducing saturation of problem colour. The mask keeps the effect to just the edges and a smaller stroke pixel setting can be used to limit the width of colour changes.  Normally for photographers, the desired change is to replace skies. With desaturation, the greying will match tones of non blue skies. If blue sky is desired then use the Hue/Sat layer but instead shift the hue of the problem fringe colour.

This is a closeup of the male Mallard duck sitting in the swimming pool with some water on the black winter pool cover.

Niels Henriksen

Monday, May 10, 2010

Black and White Iris – A Comparison Between Silver Efex Pro and Photoshop B&W Adjustment

This is a review of only 2 approaches to achieve a desired effect with a purple Iris flower. I had placed purple iris flowers in a vase, which I set in front of a white mat board. I wanted to do a study of this flower because of the great purple tones, the strong complimentary yellow colour and great curves and folds. The purple in these flowers are normally so saturated that I needed a very soft light (cloudy day, large window and not in direct light) to not overly darken the shadow areas.

It wasn't until some time later while reviewing the images again that I thought about trying to produce a B&W version.

I didn't want a high contrast image but wanted to focus on the great tones and textures as the form was already established by the image taken.

My approach is to open in Adobe Camera Raw (ACR) and then to tweak the hue saturation and luminescence for what I think will convert well with a photoshop B&W adjustment layer. I know I can do this directly with the setting in ACR but I find that I have more flexibly creating masks with colour and using ACR to separate colours further apart before bringing into photoshop.

In the image below, you can see by using the blue and magenta sliders I made the bluer tones bluer and the darker purple more magenta. This would give more control over the tones when using the blue and purple slider with the B&W adjustment layer.

I have just finally installed Photoshop on my new computer as the CS3 (windows XP) version was not migratable to the new windows 7 (64-bit) machine. With 7 processors, 12 GB of RAM and 1.8GB Nividia video card, it sure does fly. I did get the upgrade Veveza II and I thought I would play around with Silver Efex Pro that many photographers seem to enjoy.

I enjoy the B&W adjustment layer version better, mainly because I could bring out more tones, less muddy in the darker portions and I could also turn the yellow stamens white. There was considerable time spent achieving this effect whereas with Silver Efex Pro it was just a click of the button after I selected the processing type and film section.

I do like the Silver Pro version because while still soft, the contrast in texture of the vein like patterns is better. I suspect that if I were to make a final print I would combine the best parts of each through masking and blending modes.

I did add a blue/purple duo-tone and in this case more of a tint to further soften the final image.

Niels Henriksen

Monday, May 3, 2010

Form and Texture – Clouds and Tree Tops

Before Spring starts its mad dash to populate the earth with bright green foliage, the landscape can seem quite desolate.  As a photographer looking for interesting subjects, It may at times appear bleak and uninteresting. Some of us may just decide to wait it out until the glorious colours start to appear again. 

If you have time to observe, and this means more than the cursory glance, objects and subjects may appear if you can wait it out, but you need to see slightly differently.

These photos are all in Black and White because its about texture and shape, and colour would only confuse these elements.

Initially the sky was clear blue, bereft of good detail, at least with a photographer's eye.
Clouds  started to roll in from the north and I wondered if I might be able to match the cloud forms to the top of the bare trees that surrounded the fields around me.
This was not just a random thought occurrence, well it might have been, but there was some history to these thoughts.

For a long while, I had been looking at all the bare tree tops and liked their forms and texture. I just wasn't sure I could capture them in such a way as to make them interesting.

By cascading them against the cloud forms now I could add more interest and complexity to the photograph.

While the tree tops and cloud shapes have similar forms (complementary to each other) the texture is completely opposite. The clouds are very soft and almost non-existent in texture. The tree top branches are hard.

The list below highlight these differences
Clouds              Trees
Soft                    Hard
Fat                     Thin
Low Contrast     High Contrast
Flowing              Rigid
Thin                    Dense
Smooth              Jagged

In the above image I was going to crop the portion (in camera) to where the split in the branches mirrored the split in the clouds, but I found that this longer form worked better. There is more balance between mass of clouds and mass of trees. It takes softer parts to balance smaller denser part.

Down along the pathway there were these giant oak trees, like sentinels guarding the landscape.

The small solitary figure adds more interest to the image and creates a strong focal point.
The tall trees may initially capture your vision but soon the man appears and grabs your focus. Only then when the eye starts to go back up do the diagonals created by the tree branches start to guide the vision.

Sometimes it's important not to think about the actual objects that make up the landscape but to see the spaces and patterns formed and linking individual pieces together.

Niels Henriksen


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