The total accumulated exposure or dose of light on a surface is the product of both light intensity (measured in lux) and the time (hours). Example 1) 1000 lux for 1,000 hours =1 million lux hours = 1,000 kilolux hours = 1 Megalux hour. Example 2) 100 lux for 10,000 hours = 1 million lux hours = 1000 kilolux hours = 1 Megalux hour. In typical environments for painting, drawings, or photographs on display year after year, Megalux hours is the practical unit to use because the measurable light exposure dose accumulating on a print surface over time grows to very large values.
The unique record identifier corresponding to a specific test sample and its posted Test Report. ID#s are a convenient way for members who have submitted samples to locate their samples or to follow specific tests of interest as the tests progress. They also help AaI&A staff to conveniently update the records.
The manufacturer brand and model number of the printer or output device used to produce the test sample.
The brand name and description of the ink set or color forming method used to produce the test sample. The term OEM is also typically embedded in this field where applicable. OEM means “Original Equipment Manufacturer”. Searching on “OEM” in this column, for example, will help to distinguish OEM branded inkjet inks from aftermarket (i.e., third party) ink sets.
The brand name and description of the test sample’s substrate. The material is often cotton or alpha cellulose paper, but it could also be plastic, resin coated paper, canvas, metal, glass, etc.
The brand name and description of any post coating or lamination treatment done to the sample after printing but prior to testing. Note: Gloss optimizers, when printed by inkjet printers during the initial printing pass, are not regarded as coatings, rather as part of the ink/colorant process. However, if a gloss optimizer fluid is applied to the print in an extra pass through the same or other printing device, then it is listed in this column as a coating.
The test report column provides download access to individual test reports. Click on the chosen test report to download. If the test report link is colored blue, it is a free document to the public. If the link is colored green it accessible to members only. The test reports are comprehensive documents listing complete descriptions of the sample and its performance in test, and the reports are updated at routine intervals as the testing continues.
Conservation Display Rating
The Conservation Display Rating is Aardenburg Imaging’s light fastness rating for fine art and other demanding imaging applications. It quantifies the allowable exposure limits before the print sample exhibits visible color and/or tonal changes that would be of concern to the fine art market and museums and archives community. It is a more rigorous standard than is typically used in industry to rate the lightfastness of various products. The Conservation Display Rating sets lower and upper limits of light exposure which the sample can tolerate and still show little or no noticeable fade. The lower limit indicates the exposure tolerated by the weakest 10% of colors in the test sample while the upper limit indicates the exposure tolerated when all colors on average reach a threshold for just barely noticeable fade (i.e., little or no noticeable fade). Higher scores indicate more exposure is tolerated and hence the sample is more lightfast compared to samples with lower scores. Large differences between the lower limit and the upper limit indicate localized or selective color fading in the image is likely whereas a smaller difference in the limits indicates the sample will fade more evenly over the entire image color and tone scale.
The Conservation Display Rating column combines both upper and lower values in one field and will sort and filter primarily on the lower limit value and secondarily on the upper limit value. When neither limit has been reached in test, the field will show “PASS”. When the lower limit is reached but not the higher limit the field will express the range with a “+” sign on the upper limit. The “+” sign indicates that the upper limit value is at least as large as the completed test exposure to date. Hence, the “+” marked value also corresponds to the exposure interval listed in the Status column, and more exposure is required to trigger the final value for the upper limit score. See also below, the description of the columns labeled “Upper CDR limit” and “Lower CDR limit”. Higher numbers are always better. For a more detailed explanation of the Conservation Display ratings, please see the document “An Overview of the AaI&A Conservation Display Ratings” located on the documents page of the AaI&A website and also accessible from a link on the test database html page.
Lower CDR and Upper CDR
The Lower and Upper CDR columns numerically itemize the individual lower and upper limit values for more specific filtering and sorting in the database. The Lower CDR column quantifies the lower limit of the Conservation Display Rating. If the lower limit has not yet been reached, the field will show “PASS” as the value. The Upper CDR column quantifies the upper limit of the Conservation Display Rating. If the upper limit has not yet been reached, the field will show “PASS” as the value. By reporting the Lower and Upper CDR values in separate columns, more advanced searches can be made than are possible using the combined Conservation Display Rating column which is only searchable and sortable on the lower limit. The numerical values listed in the Lower and Upper CDR columns agree with the combined figures shown in the corresponding rows of the Conservation Display Rating column.
This column indicates the amount of light exposure (expressed in megalux hours of exposure) that the sample has received to date in test. Testing typically continues well beyond the exposure dose required to establish the Conservation Display Ratings and until high levels of easily noticeable fade have occurred. This column can be filtered and sorted by the numeric value in the field.
This column posts the expected date for new updates to each report. It is an estimated value, but AaI&A staff tries hard to meet the posted schedule.
All test samples are run in a batch with other samples, up to as many as 30 and usually no fewer than 15. The Batch # column makes it easy to post notices on the Aardenburg Imaging home page or News page regarding recent test updates. The latest updates can be found by filtering the database for the batch that was just updated. Batch #s also allow the end user to compare and contrast results of batch related samples with certainty that any unit-to-unit test variability is not a factor in the comparison. In other words, samples in the same batch can be evaluated as a very tightly controlled “side-by-side” paired comparison test. Aardenburg Imaging makes use of side-by-side testing as frequently as possible, for example, to compare the effects of a post coating on two otherwise identical print samples, or as another example, when comparing two print samples made with different ink sets but printed on the same batch of paper to eliminate any possible paper variability effects in the results.
Currently, the test type column can be used to readily identify and quickly filter and sort on B&W print samples versus color print samples. In the future this column will get an expanded key word set that can identify other test types such as humidity, ozone, thermal aging tests or alternate testing conditions such as Xenon lamp, cool white fluorescent, “real world” test conditions, etc.
At the present time, the sample type column lists only very basic sample type information, i.e, inkjet, chromogenic, etc. This column will be refined in the near future with additional searchable keywords such as dye, pigment, canvas, fabric, paper, RC (resin coated), to further delineate sample characteristics and allow them to be more easily searched.
Media L* Max
L* is the term for lightness in the CIELAB color model. A perfectly reflecting and diffusing surface (i.e., following a cosine function for illuminance fall-off with angle of incidence) would measure 100.0 on the L* scale. A perfect visual black would measure 0.0 on the L* scale. The Media L* max column lists the media whitepoint L* values. Typical values are above 90 with very bright white papers reaching as high as 98.0. The higher the value the more reflecting the surface and the higher appearance of visual brightness. Aardenburg Imaging reports all L*, a*, and b* values as they appear under a D50 illuminant light source. The D50 illuminant is also theoretical, but in practical terms is approached by 5000˚K (degrees Kelvin) full spectrum light sources such as commonly found in viewing booths used in the graphic arts industry. At approximately 4600˚K and with spectral output closely matching sunlight, Solux® lamps are also a very good choice to set up appropriate print viewing conditions where print color and tone fidelity can be quantitatively measured by D50 CIELAB colorimetry.
Media L* Min
A measure of the maximum printed black visual appearance (minimum lightness value). Zero (0.0) is a perfect visual black when viewed under standard viewing and surround conditions. Glossy prints typically measure less than 10 with richly printed blacks at 5 or less. Some dye-based inkjet systems in particular can achieve black levels below L* = 2.0 but this impressive blackpoint performance is often somewhat temporary as further drying of the print surface over time can alter the gloss level and raise the value back to 3.0 or higher. Fine art inkjet paper prints with matte finishes typically fall between 15 and 20 for properly printed blacks. Uncoated (plain) papers printed on inkjet papers show L* min values often above 25. Newsprint is often higher than L* = 30.
The L* range value is computed by subtracting the measured L* min value from the L* max value of the sample. 100.0 would be a perfect idealized score. Scores above 90 indicate the printing system has excellent visual contrast potential (typical of gloss and luster photo type papers), 80-90 is good, 70-80 fair, and below 70 makes for challenging printmaking because such a system is often only satisfactory when printing carefully chosen images (i.e., ones with small color and tonal range that can be accommodated satisfactorily by the limited system contrast range).