Package compiled for FAA managers

Federal Agencies Digitization Initiative Still Image Working Group -August 2010
Viewing Conditions
A variety of factors will affect the appearance of images, whether displayed or printed on reflective, transmissive or
emissive devices or media. Those factors that can be quantified must be controlled to assure proper representation of
an image.
We recommend following the guidance in the following standards-
• TSO 3664 Viewing Conditions- For Graphic Technology and Photography
Provides specifications governing viewing images on reflective and transmissive media, as well as images
displayed on a computer monitor without direct comparison to any fom1 of the originals.
ISO 12646 Graphic Technology- Displays for Colour Proofing- Characteristics and Viewing Conditions
Provides specific requirements for monitors and their surrounds for direct comparison of images on a computer
monitor with originals (known as soft proofing).
NOTE: The following are common parameters controlled by users, however, refer to the standards for complete
requirements and test methods . In particular, ISO 12646 specifies additional hardware requirements for monitors to
ensure a reasonable quality level necessary for comparison to hardcopy.
Monitor Settings, Light Boxes, and Viewing Booths
We assume the assessment of many digital images will be made in comparison to the originals that have been
digitized, therefore ISO 12646 should be followed where it supplements or differs from ISO 3664.
We recommend digital images be viewed on a computer monitor set to 24 bits (millions of colors) or greater, and
calibrated to a gamma of 2.2.
ISO 12646 recomm enrls the color tempernture of the monitor also he set to SOOOK (DSO illnmin;int) to mMch th e
w hite point of the illumination used for v iewing the originals.
Monitor luminance level must be at least 85 cd/m2, and should be 120 cd/m 2 or higher.
The computer/monitor desktop should be set to a neutral gray background (avoid images , patterns, and/or strong
colors), preferably no more than l 0% of the maximum luminance of the screen.
For viewing originals , we reconm1end using color correct light boxes or viewing booths that have a color
temperature of 5000K (050 illuminant) , as spec ified in ISO 3664.
ISO 3664 provides two luminance levels for viewing originals, ISO 12646 recommends using the lower levels (P2
and T2) when comparing to the image on screen.
The actual illumination level on originals should be adjusted so the perceived brightness of white in the originals
matches the brightness of white on the monitor.
The Room
The viewing environment should be painted/decorated a neutrnl, matte gray with a 60% reflectance or less to
minimize flare and perceptual biases.
Monitors should be positioned to avoid reflections and direct illumination on the screen.
ISO 12646 requires the room illumination be less than 32 tux when measured anywhere between the monitor and the
observer, and the light a color temperature of approximately 5000K.
Practical Experience
In practice, we have found a tolerable range of deviation from the measurements required in the ISO standards.
When the ambient room lighting is kept below the limit set in ISO 12646, its color temperature can be lower than
5000K, as long as it is less than the monitor color temperature.
To compensate for environments that may not meet the ISO standards, as well as difficulties comparing analog
originals to images on a monitor, the color temperature may need to be set higher than 5000K so that the range of
grays from white to black appears neutral when viewed in the actual working environment. The higher color
Technical Guidelines for Digitizing Cultural Heritage Materials: Creation of Raster Image Master Files 6
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