News and Views from Dave Wilson

Tag: photoshop

Fotoshop by Adobé

by on Jan.10, 2012, under Photography

This is very nicely done and scarily true from what I read of the fashion press these days.


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HDR Tip #7 – Magic Blue Sky Halo Removal

by on Mar.06, 2011, under Photography

Here’s the last of my HDR tips for this week. I’ve been saving this one for a while but, if you shoot in climates where you can rely upon clear blue skies, it’s a killer tip and could save you hours (even if I do say so myself).

Do you often find yourself with a mess like the following after tone-mapping? Frankly, this is an image I really don’t like – the tone mapping is wildy unsubtle but it serves as a great example for this tip.
Fort Bend County Courthouse (before)

The foreground looks the way it was intended to look but the sky is a horrible collection of haloes and weird areas of different shades of blue. Wouldn’t it be great if I could just drop in a new sky without having to spend a week masking around all those blasted leaves? Well here’s a tip that will fix your sky in about 2 minutes flat as long as it’s predominantly blue. This will work if there are some clouds but it definitely works best when the sky is clear.

Take a look at the original brackets you used and decide which one has the best sky tone. I typically like the -2EV image since I like nice, dark, saturated skies but it’s entirely up to you. Open the tone mapped image and the original image with the good sky as layers in Photoshop with the tone-mapped image below the original bracket.

Now we’re going to use a bit of magic that very few people seem to know about. Make sure your magnification is set so that you can see the whole sky area of the image then right click on the top layer (with the original image) and select “Blending options…” (in CS5 at any rate. It used to be called “Advanced Blending…” or something similar in some previous versions as far as I can remember and you accessed it from the layer effects list I think). The dialog that you will see allows you to control how this layer blends with the one below it and one of the great features it offers is the ability to blend based on the colours in either this layer or the one below it.

As you will notice, the bits of the tone-mapped image we want to replace correspond with the blue sky in the original image so let’s tell Photoshop to show the original only where it is predominantly blue. Do this by setting the “Blend If” option to “Blue” then drag the slider under “This Layer” to the right. As you do this, you will see that the underlying layer starts to bleed through and become visible. Move the slider to the right until you start to see chunks of the tone-mapped sky appearing then stop. At this point, you will notice something along the lines of the following:
Advanced Blending

The original sky is definitely visible but you will also see a lot of really horrid fringes around all the tone-mapped leaves. There’s another secret to get rid of these. Hold the “Alt” key and click on the slider you just dragged. You will notice that it splits in two so now grab the left hand half-slider and pull it back towards the left. As you do this, you should see the fringes get smaller and, eventually disappear leaving you with something like this:
Advanced Blending (after splitting the slider)

You will likely have to juggle the left and right half slider positions to get the best overall effect. It’s a good idea to zoom to 100% to check out the fringes since it’s tricky to see how the individual leaves (or other edges) look when you are zoomed out.

Once you have marveled at how the sky looks, you may be disappointed to notice that this blending has had a muting effect on other sections of the image too. This can, however, be corrected very easily by adding a layer mask to the top (original image) layer and, using a soft-edged brush, painting in black over the areas that you don’t want to be affected. Doing this, you are effectively allowing the underlying tone-mapped layer to shine through completely unaffected. If you accidentally paint any of the sky, just switch to white and paint the mask with that to erase the effect. Typically, the effect on non-sky sections of the image is reasonably subtle so you don’t have to be enormously careful when you are doing this final masking step. Painting this mask is, of course, enormously easier than trying to figure out how to mask around all the leaves!

Here’s the final version of the image I started with after about 2 minutes of slider juggling and some easy mask painting.
Fort Bend County Courthouse (after sky replacement)

Hopefully you’ll find this tip useful. It’s saved me hours here in Texas where blue skies are the norm. If you live up north or across the pond, you may find this less helpful but the basic approach can still be used for many other cases where you want to blend based on the colour of particular regions of an image.

I hope you’ve found this week of HDR tips helpful. Thanks for reading!

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HDR Tip #5 – Great Sky and Great Foreground

by on Mar.05, 2011, under Photography


Texas State Capitol

Quite often, I find that the tone mapping settings I like for part of my image cause other parts to look bad. In these cases, if I’m going for an artistic look, I will save the .HDR or .EXR file from Photomatix then open it twice and tone map it with settings that look good for each area independently. I then take these images into Photoshop and blend them together to give me the look I want in both areas.

If you are generating a realistic looking image, you can usually get away with not re-tonemapping but just blending in one of the original exposures. This is something I frequently do to get rid of blown highlights, noisy sections or weird contrast inversions in skies while keeping the tone mapped look of the foreground.

Open both of your tone-mapped images (or the original and tonemapped image) as layers in Photoshop with the main image on the bottom. Add a layer mask to the top image then fill the mask with black. Using a soft-edged, white brush, paint into the layer mask in the areas that you want the top image to be visible (the sky, for example). Once you’ve done this, you can change the opacity of the top layer to vary the amount of the original effect you let through.

Before anyone complains, I should admit that the picture at the top of this post is not the final version of this particular image since I’ve not uploaded that one to Flickr (you can see it on ImageKind and SmugMug though if you are interested). The final version fixes all the highlights in the clouds using this method.

I have another tip for fixing sky problems coming up but I think I’ll hang on to that one for a couple more days!

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HDR Tip #2 – Shooting Handheld for HDR

by on Mar.01, 2011, under Photography


Spaceship Earth

Continuing the week’s theme of HDR tips, here’s one that can help out in situations where you find yourself wanting to shoot a bracket for an HDR but you don’t have access to a tripod. I don’t shoot many handheld HDR brackets but sometimes I don’t have a choice – either tripods are banned or I don’t have one with me. In this case, here are a few tips that can allow you to get the shot even without your trusty tripod. For reference, the shot above is a 7 exposure, handheld HDR shot at EPCOT in Walt Disney World.

  1. If your camera allows you to shoot more than 3 shots in automatic bracketing mode, set it to bracket a couple of shots wider than you normally would. If you would normally set up for a bracket of 3 exposures, for example, set it for 5. You won’t get a chance to tweak exposures after shooting your handheld bracket if it’s not wide enough so this helps minimise the chances of you having to reshoot the whole thing if you don’t get it first time. If your camera only allows 3 shots in the sequence, stick with that.
  2. Set your camera to high speed continuous shooting mode. The idea here is that you want to hold the shutter down and have the camera rip through the whole bracket as quickly as possible. Even if you can’t shoot at 8fps, 3fps is still better than you are likely to do pressing the button once per shot so go with what you have.
  3. Set your aperture so that the longest shutter speed in your bracket will still be in the safe handholding zone (1/focal length). If you are taking a 5 shot bracket, your slowest shutter speed will be 4 times the center setting (+2EV). If you are taking a 7 shot bracket, the slowest will be 8 times the center (+3EV). Typically, I will shoot 5 or 7 shot brackets and try to get my initial shutter speed in the 1/750 to 1/1000 range with a standard lens. This ensures that you won’t have problems with camera shake at one end of the bracket.
  4. Put your feet apart, brace your elbows by your sides and hold the camera firmly against your eye. Frame the shot and then squeeze and hold the shutter trying to move as little as possible in the process. In continuous mode, my Nikon cameras will shoot the entire bracket then pause to allow me to take my finger off the shutter.

Once you’ve done all this and have your handheld bracket back in the computer, probably the most important tip is to forget Photomatix for the first part of the process. If you have Photoshop, it does a far better job of realigning brackets that are not perfectly aligned so use the “Merge to HDR” feature in Photoshop and save the file it generates as a .HDR or .EXR file. Take this file and open it in Photomatix for tonemapping.

If you practice these steps, you can usually get a pretty decent HDR even if you don’t have a good way of stabilising your camera.

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Must-have plugin for Photoshop

by on May.23, 2009, under Photography

If you are a landscape or architectural photographer who finds themselves having to touch out wires strung in front of your subjects, you should immediately head over to the Wire Worm site and download this amazing, free plug-in for Photoshop. It makes removal of nasty electric cables and phone wires extemely easy. The site also has a couple of tutorial showing how to use the filter and it’s well worth watching these before you start playing.

Thanks for Armonds at a.b.c photography for his tip about this tool.

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