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Thursday, November 1, 2007

LEVA Pre-Conference Training - Post Game Show

Calgary is an amazing town and provided a great backdrop for our training session. Unfortunately, WestJet did a number on one of my bags and most of the small items went missing, including the business cards that were given to me. So, if you are reading this and wondering why I didn't send you a note ... I'm sorry. You can contact me here.

I'm going to post a few of the things that people asked about, as far as receiving more information. The flow of this is from my recollection of events - minus the business cards as reminders, so it might not seem in any order. Here it goes ...

A great example of simple SOPs can be found on the Virginia Department of Forensic Science's web site. VA DFS Manuals. Their imaging manuals can be found here

Stabilizing your workstation - working with DVR data and exe files - virii
Faronics Deep Freeze is the product that we use to keep our systems up and running. You can throw all sorts of virii and DVR crap at this. If your system crashes, just cycle the power and you are back in business.

Forensics Defined

Forensics, or Forensic Science can be defined as applying a broad spectrum of tools and techniques to answer questions about a particular piece of evidence in the legal system. Of course Photoshop CS3 is part of your broad spectrum of tools.

What is a work flow?
A work flow is a reliably repeatable pattern of activity enabled by a systematic organization of resources and defined roles, put into a work process that can be documented and learned. We discussed the ways that Photoshop CS3 can be used within the work flow concept.

Specialized Plug-in must haves
Although we worked our images using Bridge and Photoshop, there are several plug-ins out there that can help speed things up. Some have simplified interfaces that make clarifying images a snap.
Optipix from Reindeer Graphics
Noise Ninja from Picture Code
3D Color Deconvolution from 4N6Site.com
3D RGB Color Cubes from Couleur.org

Colour Calibration
How can you accurately colour correct if you haven't calibrated your system. Here are some helpful links for each step in the process.
WhiBal Cards from Rawworkflow.com
Colorchecker card from Rawworkflow.com
ColorTune Pro from Agfa
ColorSync from Apple
Color Management, ColorThink, Profile Central from Chromix
Spyder3 and PrintFix from Datacolor
SavvyProfileSuite from Colorsavvy
ProveIt from ColorBlind
X-Rite Products 
Kodak Graphics Products
Pantone Color Control
iCorrect products from PictoColor
ColorWizzard monitor calibration software from Color 'n' Code Sàrl

Keeping up to date
The best way to keep all of your Creative Suite 3 applications up to date without spending a lot of time searching for the updates is to choose Help>Updates in Bridge CS3. Turn on automatic updates and Bridge will notify you when they become available. 

Rendering Intents
Remember - Relative Colorimetric. Shifts the colour space of the document to that of the maximum highlight values of the destination, preserves more of the original colour than Perceptual, and may be the best choice for moving from your source space to your destination space (ie. ProPhoto RGB to your printer). As with everything in the forensic world, test new ideas on your own equipment and be able to explain what you did - in case you are questioned later in court (forensics).

And, let's not forget ...

The Work flow
If your image arrives into Photoshop CS3 and needs to be de-interlaced, do so first. Some NLE products have the ability to de-interlace images on the way out. There are 4 possible choices for de-interlacing video, Odd or Even fields and duplication or interpolation as the method. Do all four possibilities and you'll end up with 4 unique images from that one frame of video. 

We discussed the merits of working in 16bpc and looked at the colour spaces with an eye for accurate reproduction of our original colours. We then recorded an action to convert our image to 16bpc and to convert the image's profile to ProPhoto RGB.

Fixing Focus
Almost all images are soft upon arrival into Photoshop. In class, we used the Smart Sharpen filter to address our focus problems. We saw that choosing Gaussian Blur as our removal method turned the filter in a fancy Unsharp Mask filter (remember the modern art masterpiece we created as a result of complimentary colour fringing at the edges). We also noted that in order to use Motion Blur as our removal method, we had to first determine the angle of the motion and put this value into the angle box. With these things in mind, we chose to use Lens Blur as our removal method, fixing focus with Smart Sharpen, Photoshop's built-in deconvolution filter. We also noted that there were some plug-ins that could help us out; namely Optipix and Clear ID (both written by Chris Russ).

Addressing Light and Colour
Having fixed our focus, we turned our attention to light and colour. We learned how to use an threshold adjustment layer, Color Sampler tool, and a curves adjustment layer to find and re-map black and white in our image in order to affect global lighting/colour within the image. We discussed ways of finding neutral gray and mapping it as well as using shadow and highlight masks to work on light and colour locally. We moved on to some specific techniques for eliminating colour casts in images.

We looked at noise on a per channel basis as well as globally. We noted that noise can appear in certain channels more than others (blue) and that there tends be more noise in the shadows. We took a relatively noisy night shot and used the Remove Noise filter, experimenting with the settings. For a sequence of images, the settings could be saved and re-loaded later in another image to speed up our work flow. We also looked at Noise Ninja, Nik Software's dFine and Clear ID for more noise removal help, noting that Optipix / Clear ID also has a JPEG Cleaner to address JPEG compression blockiness.

Removing noise and artifacts caused some softening of our image. So we looked at some additional methods of sharpening in Photoshop CS3 as well as plug-ins like Optipix / Clear ID and Nik Sharpener Pro.

Interpolation (enlarge)
There are several reasons for enlarging an image, courtroom presentations being the primary for us. We looked at the options within Photoshop CS3 as well as some plug-ins and compared the results. We looked at Fred Miranda's Stair Step method (his plug-ins for CS3 aren't out yet) and again with Optipix / Clear ID (I'm trying hard not to sound like a salesman for Ocean Systems). We also looked at what happened if we wanted to use the printer's driver to interpolate.

Sharpening (yes, again)
Our efforts at interpolation softened the image, so we hit it with one final pass of sharpening. We chose to use the High Pass sharpening method, employing the Overlay blending mode as a contrast multiplier.

We talked about printing, manual adjustments for aspect ratio (rather than preview), contact sheets, archiving, and sharing of files with others. 

It was a full 16 hour session with so much information being discussed ... but everyone did so well on their final assignment / test.

It was my pleasure to present Beginning to Advanced Imaging Techniques at LEVA this year. If you missed it and want to see what it's all about, ask Jan to run it again .

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