Layered Contrast

Here is a Photoshop technique for contrast that uses layers, one for the lights and one for the darks. Contrast can be adjusted with many commands in Photoshop: Brightness/Contrast, Levels, Curves, Exposure, to name a few. Layered contrast provides certain kinds of control you can’t achieve with the other commands. I’ll describe it step by step for you, by way of explanation, and also provide a downloadable action.

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High Pass Enhancements

Photoshop’s high pass filter can be used with layers to achieve some very useful image enhancements. This post discusses how to increase or decrease contrast along object edges and provides a few downloadable PS Actions. High pass edge contrast enhancement is a standard trick for adding “punch” to images: you probably see it all the time without even realizing it. Edge contrast reduction is a logical consequence of edge enhancement. It could be used as a “softening” filter, but probably qualifies as an “effect,” since it runs counter to expectations for good images. In other words, it’s just waiting for someone to exploit its potential.

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Statistical Blending

You can use statistical blending to render high dynamic range images, to reduce noise, or to create multiple exposure effects in Photoshop (CS4 extended edition). All these techniques require that you have multiple images to start with. For HDR images, you need different exposures of the same subject from a stationary viewpoint. The same is true for noise reduction, only the exposures should be identical. Multiple exposure effects can use any number of different images, all of the same dimensions. In each case, you start by stacking all the images into layers, selecting all layers, and converting them into a smart object. Then you use the Layer > Smart Objects > Stack Mode functions Mean or Median to create a statistical combination of all the images, which you can rasterize. Details after the break.

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Worthy of 16-bit Printing

Is there really any difference between printing with 8-bits per channel and printing with 16-bits per channel? I’m not sure yet, but I’ve been dealing with a photo that could reveal the difference. It has some very fine, continuous gradations–exactly the sort of thing that Epson says is worthy of 16-bit printing on the 9900.

Evening light

Evening light (Alma de la Serra, 2009)

I’ve been printing this on Hahnemühle Photo Rag (HPR), an exquisitely unforgiving paper. I reveals every glitch–which is to say, it’s a fantastic paper, capable of recording the finest nuances. I’ve been printing this 16-bit/channel image in 16-bit/channel resolution, and have been very gratified with the results.

Dust has been the only problem. Ink on HPR will not bleed into the gaps left by tiny particles, nor does it have a texture that will hide specks. This particular image really shows such flaws. I throw out about a third of the prints, looking for perfection. Nothing else will do. I haven’t had this problem with other papers–but maybe I’ve just been lucky, or there’s more static charge on HPR. In going digital, photography has not left dust behind.

Incidentally, this is a high dynamic range image, a composite of 5 images. I used qtpfsgui to composite and tonemap the image and finished the processing in Photoshop CS4. Qtpfsgui/ Luminance HDR is an open source application for HDR workflow. It doesn’t have the bells and whistles of Photomatix or Photoshop, but it gets the job done, once you grok the interface.

This print and a few others by Alma de la Serra will be on view at Transistor over the coming weeks.

ColorMunki Quirks

The ColorMunki color profiling device from XRite is one of the core technologies of my color workflow, but it has its oddities. Fortunately, there are some workarounds–and where there are none, patience is a virtue. Profiling a second monitor presented some difficulties, and the device has some ergonomic design shortcomings. You also have to learn to deal with a few good features.

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Feed Your Home Page

With the help of Magpie, feed2js, and jQuery I added feeds of my blogs to my home page at ignotus.com. I wanted a solution that would let me tailor HTML markup and CSS styles to my liking. I discovered quite a few services that will aggregate feeds for you and then let you install a widget within a page, some of them apparently quite useful–as this post at Wild Apricot Blog explains. However, I really didn’t want to depend on another site and I initially only needed to post my own, local blog feeds to my home page. Drupal can handle feeds, of course, but I wasn’t enthusiastic about swapping Drupal in for my home page. Powerful though Drupal is, it is far from transparent, especially if you want to port a pre-existing design of your own into Drupal. WordPress blogs that I had already started provided more tools for customization and page creation than Drupal blogging offers. No jQuery widget that I looked at quite fit the bill either. I settled on feed2js because I could completely tailor the processing of a feed and its HTML output with some PHP and jQuery coding to get it massaged into shape. The fact that it was written by someone I knew and whose code I trusted was a clincher.
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Curl before feeding

Rather not hear the sound of paper popping and crumpling as it jams a printer? Curling the corners of cut sheet paper back makes them less likely to get mangled in the paper slot or worse yet in the platen gap or the printhead.

Cut sheet paper often seems to curl up at the corners on the print side. This may be a result of its treatment with image enhancers and paper brighteners that make it respond to humidity differently from the back side. In any case, the remedy is as simple as curling the corners back just enough to keep them from sticking up and getting caught in your printer. Setting the platen gap to accommodate heavy or light weight paper is also important, but won’t prevent jams caused by curled up corners. Thanks to Larry Danque for this tip.

IgnoFactory Arrives

IgnoFactory, a blog at paulhertz.net, covers technical topics in digital art, including printing and image processing techniques, code, design, etc. It includes pages on Ignotus Editions, a fine art printing service, and on the artists of the ignoStudio.

For the curious, there are other blogs at ignotus.com. Mnemonic Spumoni deals with the lives, times, memories, work and opinions of the four artists represented at paulhertz.net (Paul Hertz, J.T. Pescador, Alma de la Serra and Darrell Luce). It\’s our social blog. Intermedia Patterns is a scholarly research project Paul Hertz and Jack Ox have been working on, pooling their ideas about intermedia art. There a various projects linked to our home page, too.