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white-on-blue photographic print, commonly of a working drawing used during building or manufacturing. The plan is first drawn to scale on a special paper or tracing cloth through which light can penetrate. The drawing is then placed over blueprint paper, prepared with a mixture of potassium ferricyanide and ammonium ferric citrate. When the attached drawing and the blueprint paper are exposed to a strong light, the unprotected ferric salt not lying beneath the lines of the drawing is changed to a ferrous salt that reacts with the ferricyanide to form Turnbull's blue. This blue is the background of the finished print. The ferric salt under the lines of the drawing, protected from the light, remains and is dissolved during the washing in water that follows exposure. As a result, the lines of the original drawing appear white in the finished blueprint.
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A reproduction of a drawing by a contact printing process on light-sensitive paper, producing a negative image of white lines on a blue background; refers to architectural working drawings for construction.
Illustrated Dictionary of Architecture Copyright © 2012, 2002, 1998 by The McGraw-Hill Companies, Inc. All rights reserved


(graphic arts)
A contact print, with white lines on a blue background, of a drawing; made on linen or on ferroprussiate paper and developed in water or a special solution.
A photoprint used in offset lithography or photoengraving for use in checking positions of image elements.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.


a photographic print of plans, technical drawings, etc., consisting of white lines on a blue background
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005
References in periodicals archive ?
The old system of operation by singleowned stage carriage permit holders/ Blueline bus operators is no more feasible, advisable or permissible." " The fundamental right to life takes precedence over all statutory rights.
Singh, appearing for the Blueline operators, however, contended that the figure was misleading and that the Capital would face hardship if the buses were taken off the roads.
The Blueline operators opposed the government stand and contended that there has been drastic decline in the number of accidents involving the buses.
The Delhi government had earlier announced that all Blueline buses would be taken off the Delhi roads by December 14.
According to a source, many of the drivers from the Blueline buses could be taken into the DTC fold after formal re- training or on simple contract basis to fill up the shortfall, though not all in the transport department are for the idea given the abysmal safety records of the drivers.
What's more alarming is that the government's plan could push the current process of phasing out the Blueline buses from the Capital's streets to the back burner.
The Bluelines were to follow DTC's timetable and have a DTC conductor ( ticket collector) onboard.
The process of phasing out the Bluelines has already been delayed because the bus owners had approached the Delhi High Court.
The first fatal accident involving Blueline buses after the Commonwealth Games was reported on Saturday when an overspeeding bus mowed down a biker near Ashram crossing.
The Bluelines were taken off certain stretches of Delhi ahead of the October 3- 14 Commonwealth Games.
Government officials claimed there were enough Delhi Transport Corporation ( DTC) buses to deal with the shortage of Bluelines. However, the frequency of DTC buses on Monday was low.
They break traffic rules and have killed 94 people till October 15 as compared to 102 in the corresponding period last year despite a decrease in the number of Bluelines on the road.