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An Overview of the Aardenburg Imaging Conservation Display Ratings

Posted: 2009-01-18  Revision: 2009-02-05
by Mark H. McCormick-Goodhart

This paper gives a basic explanation of the Conservation Display ratings published by Aardenburg Imaging and Archives in the lightfastness test results database. The conservation display ratings are a fair measure of the performance of digital print media with respect to the retention of print color and tonal fidelity in the early stages of deterioration upon exposure to light over time.

An Introduction to the I* Metric

Posted: 2007-02-11  Revision: 2007-07-24
by Mark H. McCormick-Goodhart

This paper discusses the basic concepts of the I* metric without encumbering the reader with mathematics. However, it does compare and contrast the I* metric to the color difference model (∆E), and it assumes the reader has some familiarity with color managment, Photoshop’s LAB mode, and the use of ∆E in digital imaging applications.

A “Retained Image Appearance” Metric For Full Tonal Scale, Colorimetric Evaluation Of Photographic Image Stability

Posted: 2007-02-11  Revision: 2007-02-11
by Mark McCormick-Goodhart, Henry Wilhelm, and Dmitriy Shklyarov

This document lays out the concepts and mathematics of the I* metric. Discussion relates to use of the metric in image permanence research. Reprinted with permission of IS&T: The Society for Imaging Science and Technology sole copyright owners of IS&T NIP20 Conference Proceedings.

Case Study #1 Evaluating the Influence of Media on Inkjet Tone And Color Reproduction With the I* Metric

Posted: 2007-02-20  Revision: 2007-03-07
by Mark H. McCormick-Goodhart

This case study uses the I* metric to evaluate the color and tonal reproduction of three different media printed on one inkjet printer with same batch of ink. An Epson R1800 printer with Epson OEM ink was used to make prints on Epson Premium Luster Photo paper, Epson Matte Paper Heavyweight, and HammerMill Ultra Premium Inkjet paper.

Case Study #2 A Year in the Life of an Inkjet Print – Environmental, Colorimetric, and Visual Assessments

Posted: 2009-06-10  Revision: 2009-06-10
by Mark H. McCormick-Goodhart

An ongoing environmental study of a modern pigmented inkjet print, framed in a conventional wooden picture frame with standard acrylic glazing, acid-free matting and mount materials. Results are presented for the first 18 months of display.

On the Permanence of Photographs, Laboratory Testing, and Real World Behavior

AaI_print permanence.pdf
Posted: 2007-09-26  Revision: 2007-09-26
by Mark H. McCormick-Goodhart

Some thoughts on the permanence of photographs and how to test for real world aging behavior.

The Allowable Temperature and Relative Humidity Range for the Safe Use and Storage of Photographic Materials

Posted: 2007-12-06 Revision: 2007-12-06
by Mark H. McCormick-Goodhart

Originally published in the Journal of the Society of Archivists, UK, Vol 17, No.1, 1996, this article discusses key preservation issues related to traditional photographic film and print collections. The conclusions and storage and display recommendations are also highly relevant to today’s modern digital hardcopy print technologies.

On the Cold Storage of Photographic Materials in a Conventional Freezer Using the Critical Moisture Indicator (CMI) Packaging Method

Posted: 2007-12-06 Revision: 2007-12-06
by Mark H. McCormick-Goodhart

The author was the Senior Research Photographic Scientist at the Smithsonian Institution in Washington DC when this unpublished paper was written. It was written to document a new method for safely packaging photographic materials for long term storage in conventional freezers. Subzero temperatures can dramatically increase the longevity of photographic materials, but some basic handling procedures must be followed. The CMI method for the cold storage of photographic materials has over the past decade been implemented for small photographic collections at numerous museums and archives, and by individual photographers for their personal collections all over the world.

“Hue Slice” Image Test Target

Posted: 2008-02-23 Revision: 2008-02-23
by Mark H. McCormick-Goodhart

Posted primarily for “ColorGeeks”, this image file reveals the Hue planes of the LAB encoded Colorspace, ie., it contains image pixels from -128 to 127 a* and b* values along the dynamic L* range from 0L to 100L. By using the Hue slider window in the included Hue/saturation layer (labeled “Hue Slice Chooser”) while leaving the saturation and lightness fields empty, one can interactively “spin” the color plane through all 360 degrees of Lab Hue planes. To determine which CIELAB Hue plane is selected add or subtract the number in the hue slider bar from 0/360 degrees. Additionally, when used in conjunction with softproofing and the PS Gamut Warning function turned “on”, and by again interactively working with the hue slider window, one can visualize what LAB colors associated with the selected hue plane will convert through the destination profile and chosen rendering intent within gamut or out of gamut. Adobe’s allowance for converted color error when comparing out of gamut vs in gamut results appears to be about 5 Delta E. In other words, if the profile conversion predicts that the destination color will be within 5 delta E of the source color the PS gamut warning color is not overlaid in the image. Please note: this error limit can only be properly assessed when using ABScol for rendering intent and BPC turned off in the color settings conversion dialogue box. Otherwise, the color changes to the source data from the applied rendering and BPC compensation are not measured by the photoshop info tool.

On the Use of Data Loggers in Picture Frames (And Other) Micro Climates

Posted: 2008-04-22 Revision: 2008-04-21
by Mark H. McCormick-Goodhart

This paper is a brief discussion on the use of data loggers in the Aardenburg Imaging Digital Print Research Program, and it offers some basic guidance on how the interpretation of data collected in micro climate environments differs from the interpretation of data collected in macro climates where air circulation is usually more plentiful. The paper was prepared for the Archives Conservation Discussion Group session held at the 36th Annual Meeting of the American Institute for Conservation of Historic and Artistic Works in Denver, Colorado on April 21-24, 2008.