Graphic Arts Technical Foundation REHM Light Indicator Targets.
I have used this device for over 15 years and used correctly
it ensures that
you always evaluate colour in a correctly lit environment. I carry one in my
wallet - stuck on the back of my drivers licence so I always have one at the
ready!
I have just 20 boxes in stock and when they are gone, you will need to source
them from the US.
(Minimum purchase from GATF was around $1000 USD
last time I purchased them.)
The GATF RHEM Light Indicator provides visual Indication of correct lighting conditions.
People involved in colour management know the importance of viewing prints and
transparencies under controlled lighting, normally a viewing booth with D50 or 5000K lights.
Using a RHEM strip, the person viewing can easily see whether they are working in good or bad lighting and take some action.
Its amazing how many PRO labs don't have colour
correct viewing areas where clients pick up
their work. You simply can't assume that you are
viewing your work under standard viewing
conditions. The GATF RHEMŪ Light Indicator is a device for the visual control of colour viewing. When attached to the border of a colour print or transparency, the Light Indicator will signal whether the viewer is judging colour accuracy with or without a 5,000 K standard light source. Under standard lighting, the Light Indicator appears as a solid magenta patch. However, under non-standard light sources, the broad stripes of the two magenta metameric colorants that comprise the Indicator are readily apparent. The small patches, backed with a non-permanent adhesive, can be peeled off and attached to the border of colour prints, colour reproductions, or the sleeve of a transparency. Each patch measures 2x0.75-in. (51x19 mm).