articles/Lightbox/gtiodv-page1
by Mike McNamee Published 01/02/2012
Sides provide better light control for critical comparisons.
The smaller booths fold up for easy transport.
The GTI PDVe Print Viewers Every now and again your editor comes up with a good idea! This year's offering was to ask GTI to provide viewing booths to assist in the judging of the 16x20 competition and also to provide a controlled viewing of occasional, single prints from Fellowship application panels.
The viewing booths suggested by GTI were their PDVe series and specifically the PDV3e which is sufficient size for the 16x20-inch mounted print. This unit has optional side panels which we chose to remove to facilitate print handling from both sides of the booth, even though this made the lighting pattern slightly more uneven.
The units are well constructed but light enough to be carried folded up. The light tubes (usually called luminaires in this class of kit) are set in the upper fold-out 'roof' to the unit and equipped with a detachable baffle to prevent any direct glare from the tubes. An additional feature (not needed this time) is the ability to clip an unmounted print into the viewing surface (think X-Ray viewer from ER) and additionally hold a curved print, with the aid of two magnets.
Light Quality
It is not possible to achieve even lighting in the vertical plane from a top-illuminated system. In larger systems for pressproof grading, the prints are viewed either horizontally or at least only a modest angle. This arrangement is unsuitable for a public judging such as ours when both the judges (five) and the viewing public need a good view of the prints from all around the room. Even so, at no stage was the uneven top to bottom illumination an issue, the eyes accommodated quite well and we were, after all, just looking rather than comparing 'match prints'.
The light quality was assessed against ISO 3664 using a GretagMacbeth Eye1 Pro and Babel Color software. The light was quite good on rendering index, measuring the required 90+ over the surface, other than the very bottom of the area.
The colour temperature was 4,800°K against an aim point of 5,000°K. The Metamerism Index was between 0.66 and 1.00, OK for Grade C viewing but outside the Grade A and B sometimes used for really critical proofing work. The light, then, was well suited for the purpose.
TOP LEFT: The GTI viewing booth in operation at the Convention 16x20 judging.
BOTTOM LEFT: 'Isolux' contours of the GTI box.
Top-lit boxes cannot maintain even lighting down the viewing area but are still very serviceable in everyday viewing.
TOP RIGHT: GTI do an excellent three-light demonstration viewer. One should be on show on the Imaging Warehouse stand at Focus and should provide you with a convincing demonstration of the importance of viewing light!
BOTTOM RUGHT: A BabelColor report of the Professional Imagemaker viewing booth, which passes the highest ISO grading.
Overall
The use of the units was a great success and favourably commented upon by both judges and the audience. Without the sides we were able to gang together up to three units so that as many as four finalist prints could be viewed in high-quality, even light. Only glossy,
cockled prints caused any real issues but this is a problem that has no real solution. The very high level of illumination (over 2,000 lux) provided strong lighting even with the room lights left on. Overall then this was one of McNamee's better ideas!
We have often been asked by enthusiasts about suitable viewing stands for camera clubs. These fit the bill nicely and their ability to deal with un-mounted prints, and also to fold away, is a real bonus.
GTI Booths can be viewed at www.gti.com and are distributed by The Imaging Warehouse and Colour Confidence. They may be seen at Focus on Permajet's stand B12, (also including The Imaging Warehouse and Breathing Color).
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