Rags Int., Inc.

Digital Technology Articles

From time to time, I will post some personal comments related to digital photography here.   My selfish goal is to write things down as I learn them.   This reinforces the learning process for me.   Having done that, I would like to share my observations for the benefit of other photographers.   Be prepared for some potentially controversial concepts.   I tend to take a systems view of technical topics that prerequisites an accurate conceptual understanding of all the components.   I also tend to resist "group-think" so I sometimes find myself swimming up-stream.   Your Email feedback and comments are always welcome.  

Digital Trivia

Film versus Digital Camera versus Vison DOF and Diffusion
Demystifying the Confusion
Tones and Zones Sensor Color Pipelines The ETTR Myth
  Raw File Standards
The answer's 42,
What was the question?

Just for grins, I decided to jump into the film versus digital debates.   The second link looks at some similarities and differences between a camera and human vision.   The DOF link contains some notes on the circle of confusion for depth of field calculations.   This was predicated on the impact of the digital (such as Nikon DX) sensor formats.   The Tones n Zones article is to a discussion about a mythical relationship between binary image tone numbers and exposure zones.   The Sensor Pipelines article is an under the covers look at how colors are reproduced from a typical Bayer sensor layout.   The ETTR Myth topic addresses some comments that suggest that the histogram should replace your light meter.   Then, when the debate over standards for raw image file formats heated up.   I decided to jump in there as well.

Digital Camera Calibration Topics

ACR Calibration Color Calculator Macbeth CC Lab Values

The ACR Calibration Scripts provide a form of automation for adjusting the Photoshop CS ACR sliders for color calibration.   These scripts will support GMCC, IT8, or QP201 targets.   They have many options for calibration of difficult images.   The Color Calculator link contains sample scripts that I used to validate the color math in these other scripts.   These might be of some interest to a few folks that would like to understand the math in more depth.   The final link, Macbeth CC Target Values, discusses the CIE Lab numeric values for the sample patch colors.   It also has a link to some scripts that can be used to create and evaluate new Color Checker targets.

Adobe Photoshop CS Scripting Topics
Workflow Automation Plus

Photoshop Javascript Sports Template Collage Builder
Neat Image Get Files From Bridge Calculate Utilities

These links demonstrate some sample Photoshop JavaScript Utilities.   The PS JavascriptUtilities include one that simply resizes images, another to add copyright information, and one that can add a logo or custom vector shape and the filename to an image.   These all address the issues of image orientation, upsizing or downsizing, and changes in the aspect ratio.   The sports template is useful for building sports event trading cards.   The collage builder will build and load images to various collage template layouts.   The Neat Image script assists with noise reduction in batch workflows.   GetFilesFromBridge gets a list of images from the current CS Bridge selection and allows you to run up to five scripts and two actions against them.   This is very useful for CS batch automation.   Calculate Utilities include exposure, dynamic range, and Depth of Field.   All these sample scripts are available in ZIP files.

If you are interested in custom scripts for your specific workflow needs, please contact me.   For a reasonably small fee I would be happy to build them.

Digital Printing and Output Topics

Color Management 101 Digital Image Projectors Epson Stylus Photo 2200

The color management link is to a web based PowerPoint presentation used for a local camera club class.

The Projectors topic briefly discusses three projector technologies and describes some considerations for evaluation for use with photographic images.   There are also some test images that can be downloaded.

After installing a new Epson Stylus Photo 2200 Printer for larger prints, I discovered that the printer resolution is not adequately stated.   This article discusses the metrics and relationsdhips of PPI, LPI, and DPI.   I hope that these can save some time and frustration for others.  

Histograms and Exposure Topics

Digital Histograms Exposure Matrix Light Measurements

The links above relate to photographic lighting and measurements.   The first link is to an introduction to reading digital histograms.   The next link is to a discussion of genedral exposure calculations, lighting ratios, flash guide numbers, and an Excel Spreadsheet full of exposure formulas.   The last link is to an article covering basic light measurements.  

SLR Lens Topics

SLR Lens Properties
and Terminology
Resolution Tests

The first link is an introductory discussion of lens properties and some of the more basic formulas.   Topics include focal length, focus, magnification, and field of view.   A link is provided to an Excel Spreadsheet if you want to explore the formulas.   The second link is to the results of some comparative tests of lens quality using a convergence/resolution test target.  

The fine print:.   All statements, technical information and recommendations herein are believed to be reliable.   The conclusions herein are the opinions of Rags Gardner and are not meant to represent or miss-represent the claims of any manufacture of any equipment referenced.   Information published within the site is intended solely for the purpose of providing general information specifically with the intent of enhancing the readerís knowledge of technical concepts.   Rags Int., Inc. assumes no responsibility for end use applications, and no performance warranty is expressed or implied.   Rags Int., Inc. respects your privacy and does not request or re-distribute personal information.

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Rags Gardner
Rags Int., Inc.
204 Trailwood Drive
Euless, TX 76039
(817) 267-2554
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