I am back from Indiana where I gave a seminar on Photography, Lightroom and Photoshop. Many thanks to a great group of people at the Goshen Photography Guild for their support for the program which sold out the available seats. The venue was great and the experience was wonderful and fun.
The day after the seminar a group of us went after images at Michigan City along the lake with the Chicago skyline visible (slightly) in the distance. Some were hoping for a sunset with the skyline, but cool air and wind were there instead.
As is typical when giving a seminar, you never know how the questions and overall flow will go until it happens. I wanted to include a section on image sharpening which time did not allow. So, I want to direct people to my Learning Page for more information and in particular the two articles, Smart Sharpen , and the High Pass Filter for sharpening images. There are, of course, many other ways to sharpen images, but these two are both powerful, versatile, and the most used.
The two gulls in the photograph above were surprisingly cooperative considering the exposure time for the image was 20 seconds. This was done with the aid of a neutral density filter that allows the moving water and clouds to appear as smooth tones rather than fine detail, while stationary content is registered in a normal manner. Great fun.
On my Learning Page (see link in the main menu) I have posted a new article, the second in a series on blend modes. This time we explore two members of the Darken group. These apply to both Photoshop and Elements users. They are simple to use, and valuable additions to your tools for controlling your images. Please read the article, which is short and to the point, and try the techniques yourself. I will be running seminars very soon on advanced techniques for processing fine art images in Photoshop and Elements. The blend mode article will be good foundation material for getting you up to speed before attending one of these seminars, especially if you are an Elements user.
I recently spoke to the Hershey Camera Club on the subject of lighting and on-camera flash. This is a subject that can get pretty involved and I was hopefully able to impart a sense of the scope of the subject to those who attended. Feedback on the meeting was good. I would like to run a hands-on shootout on flash photography at some point in the near future. If you think you might be interested in such a seminar, please send me an email using the link on the Learning Page. No obligations at this point, but I would be interested to know how many people may find this interesting. It may be that there will be two events, one for beginners who do not have hand held incident light meters and want to learn to use the flash actually on the camera, and a second more advanced seminar for meter owners including off camera flash. The techniques for marrying flash with ambient light can be confusing, but I can teach you the concepts of the technique pretty quickly if you are interested in more control over your lighting.
Local area events coming up very soon include the Harrisburg Camera Club Spring Workshop April 13, and the Camp Hill Plein Air event May 18. More detailed information on both of these events are in the newsletter on the Learning Page of my website.
A common failing in many images is non-existent or badly done sharpening. I hope if you are working in digital imaging that you already know to avoid the three filters that actually start with the word “sharpen” in the filters list. Smart Sharpen and Unsharp Mask are much better choices. In addition is a technique not shown in the sharpening options, but using a filter that “passes” high frequency information. In real world terms that means “edges” to a photographer, and is the opposite of a “low pass” filter, which is Gaussian blur. This is a fairly simple and easy to use sharpening technique, especially for portraits.
The technique requires a blend mode be applied to the layer as well as the high pass filter itself. This is best done on a merged visible layer at the top of the layer stack saved as a psd. That makes it easy to remove and replace should the image need to be repurposed, resized, or otherwise manipulated. In a finished image it can be applied to a duplicate layer. The primary decision for all sharpening is output destination and size. The sharpening for a small web image will be insufficient for a high resolution file aimed at producing an 11×14 inch inkjet print. Conversely, the print sharpening will be far too aggressive for the web image.
The High Pass technique essentially finds edges and when coupled with a contrast blend mode like Overlay results in increased contrast at the edges giving the appearance of sharpening of the image. Smoother areas of the image are ignored which helps to make the process even more valuable. For example, High Pass sharpening of about 1 pixel on a portrait will sharpen the eyes and hair while ignoring the skin.
The effect can be reduced by using the Soft Light blend mode and/or reducing the opacity of the sharpening layer. Small images can use High Pass settings as low as .3 pixels, and some larger images can benefit from larger radius settings. Experimenting and analyzing the results is something the beginner needs to do to gain an understanding of how the process works.
Find the dialog under Filter | Other | High Pass and choose a setting appropriate for the image size. When you click OK the layer will turn gray with slight lighter and darker edges defining your subject edges. Change the layer blend mode to Overlay to start, and click the layer on and off to see the effect. This is best done with the image on screen at 50% or 100%. A 50% view more closely shows the result as it will appear on a print. Edges you would prefer remain unsharpened can be masked off if needed.
A full article explaining the technique with illustrations is on my Learning Page (see link at top). Check in there (refresh your page if needed to get the latest version).
You sometimes need a current representation of your file to make selections. I work a lot with Color Range for selections, and it is convenient to make a merged visible layer to use as source material for this. If you are not familiar with this technique, simply make the top layer of your psd the active layer and then use “merge visible” in the layers drop down adding the (<alt>) [<option>] key to prevent the layers from flattening. The keyboard shortcut is (<ctrl> <alt> <shift> E) [<cmd> <option> <shift> E]. This creates a new layer at the top incorporating all the layers below into a single layer, much the same as flattening the file but retaining the file layers below it.
I use this merged visible layer as the source for making the selections. If there are several adjustment layers at the top of your stack you will discover that selecting with a non pixel layer as the source will result in no pixels being selected. Making the merged layer and using it for the source will solve the problem.
Once your selection is made you can add an adjustment layer, or jump the selected pixels to a new layer for more work. With this done I drag the merged layer to the trash. This keeps you from expanding the file size for one thing, but also eliminates the loss of the ability to modify the layers under the merged layer. Keeping your pixel layers at the bottom helps you maintain flexibility.
Another good use for the merged visible layer is sharpening. I use a merged visible layer at the top of the stack for sharpening at the end of the process. This layer can easily be removed if necessary to make changes in the file, or modify the sharpening technique. Sharpening can also be adjusted based on output and sizing parameters. Adding a mask to the sharpening layer allows local sharpening, and adding layer style modifications using BlendIf can protect highlight and shadow areas from clipping with some sharpening methods.
Most images can benefit from an increase in mid-tone contrast. This is especially true of B&W images, landscapes and high frequency image content such as textured detail. There are a number of different ways to increase the mid-tone contrast. Since most of them are global there is an unwanted increase in the overall contrast of the image which can drive highlights and shadows into clipping and a loss of detail where we do not want that to happen. Restricting the added contrast to the mid-tones or a specific tonal range is fairly simple process.
You can add contrast with curves, shadow/highlight, and other controls, but one of my favorites is the low contrast, high radius unsharp masking technique. First we will add the contrast and then tame down the effect on the high and low values.
Duplicate your background layer and put the new layer in luminosity mode if you want to restrict the effect to the image content and not the color. Using Filter | Sharpen | Unsharp Mask, set the radius to a much higher number than you would normally use to sharpen an image. We want to have the sharpening halos to be so large as to disappear into the image and not be seen. While this is somewhat image resolution dependent, the effect will work without specific radius numbers being important. So, try 50, 87, or 122 pixels and notice that the difference is subtle if even noticeable. Set the threshold to zero to start as we want the effect to influence the entire range of the image. You can play with larger threshold numbers if you need to soften the effect, but that should be easily controlled with layer opacity.
The contrast will be controlled by the Amount slider and the setting for that is lower than normal. It takes about 10% to be noticeable, and somewhere around 20-25% works well. Higher numbers may produce more contrast, but that isn’t really necessary for the effect we are looking for. A reasonably useful set of numbers for me is Amount 20%, Radius 80 pixels, Threshold 0.
Now we control the effect by using the Blend-If sliders in the layer style dialog accessed by double clicking in the blank area of the layer or clicking on the fx at the bottom of the layers pallet and choosing Blending Options. At the bottom of the Layer Style dialog box you will see the following area which is known as the Blend-If control. We are working on the layer we need to control, so This Layer is the place to work. Drag the left slider to the right to about 10-15 and hold down the <alt>[option] key to split the slider and drag the top half of the slider to about 40. Splitting the sliders requires a little getting used to, but soon becomes easy to do. At the right end you want to drag down the highlight slider to about 240, and split the lower half to about 200-210.
Splitting the sliders is the equivalent of blurring a mask edge to make the transition area of the effect softer and less noticeable and helps you blend the sharpening effect out of the brightest and darkest areas of the image. In this case we are telling Photoshop to have no effect on tones above 240 or below 10 and gradually increase the effect so that 100% is applied between values of 40 and 210. The specific numbers are arbitrary and can be modified to suit your image. However, the overall effect is rather subtle and an action can easily be made that would make all of the above settings happen automatically to a layer. The result will be added contrast to the mid-tones of the image imparting more snap and the appearance of a sharper image without clipping highlight and shadows.
Here is a portion of a high frequency image with and without a mid-tone contrast boost. In the finished image the highlight and shadow values are maintained at the level prior to the contrast boost.
Adobe has announced a security update for CS5 and CS 5.1 for both Mac and Windows.
This update addresses vulnerabilities that could allow an attacker to take control of the affected system. For an attacker to exploit these vulnerabilities, a user must open a malicious TIF or DAE file in Photoshop CS5.1, Photoshop CS5, and earlier. Adobe is not aware of any attacks exploiting these vulnerabilities against Adobe Photoshop.
The update is available at the following location.
I have seen several images recently that suffered from insufficient or inaccurate processing the raw converter. How can I tell? In most cases the high values are the tip off. Initial processing in the raw converter should contain the values of the image within acceptable limits for reproduction including printable highlight and shadow details. If a highlight value in a portion of the image is brighter than it should be and further processing in Photoshop did not raise the value somehow, then the initial raw processing was incorrect.
An accepted technique for raw processing is the hold down the <Alt>[Option] key when moving the Exposure slider to see if any channels are clipped at the high end. Making the on screen display black except for specular highlights is a good start. However, it is usually better to go beyond this to establish a target value for a detailed highlight area and make that value work by lowering the Exposure. This will pull down overly bright high values, especially in skin tones and other bright subject matter that should have full detail. This is generally not hard to do. Processing those areas later in Photoshop is occasionally necessary for added detail, but there is no reason why a value that should be around 230 should be processed to 250 as a starting point.
The occasional image that exceeds a reasonable contrast range may require a double processed raw file and subsequent tonal merging to reign it in, but that is generally not the case with most images. It is far easier to control the overall values of an image in raw where there is more information available in the file. Saving hot areas in Photoshop requires more work and generally results in lesser quality in the final image. Why work harder than you need to.
I suggest that photographers with a lesser knowledge of a good workflow in raw take advantage of the changes in the processing in the CS6/LR4 raw processor to learn better control while familiarizing themselves with the new interface. This is not difficult to do, and the results will be more than worth the effort. Conceptually, there are only a few primary target values to aim for and the result will be files that are easier to finish once they are opened in Photoshop.