Automated color separation

UNITED NATIONS

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Secor.d Uni ted ~lations Regional

Cartographic Conference for Africa

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This document is

by the USA Government

AUTOMATED COLOR SEPARATION

Prepared by Joe Steakley

Aeronautical Chart and Information Center United States Air Force

St. Louis, Missouri

The views expressed herein are those of the author and do not necessarily reflect the views of the U. S. Air Force or the Department of Defense.

For distribution at the

Second United Nations Cartographic Conference for Africa Tunis, Tunisia

12-24 September 1966

DEPARTMENT OF THE AIR FORCE

HEAOQUARTERS AERONAUTICAL CHART AND INFORMATION CENTeR SECOND AND ARSeNAL, ST LOUIS, MISSOURI 63118

AUTOMATED COLOR SEPARATION

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Joe E. Steakley

Technical Planning Division Directorate of Operations ACIC

8 March 1966 ABSTRACT

Recent developmental work in scanning devices and plotters has pro- vided a potential to improve productivity in color separation. The

necessary separation of colors, for lithographic plate making, is a purely deterministic process. It involves rigorous specifications, but no car- tographic license is given the negative engraver. ACIC plans to make this conversion in three steps. Model I will be a semi-automatic color separation system, Model II will be an automated color separation system, and Model III will be an automated color separation system with on-line planimetric revision and editing capabilities.

INTRODUCTION

ACIC has been aware of color separation costs, in terms of dollars and calendar time, for many year s . However, it has only recently become feasible to pursue development of an automated system to relieve us of this tedious, time-consuming task. Significant advances have been made in precision line plotters; scanning deVices that can discriminate between several colors; electronic displa,y systems, combining a CRT and rear- slide-projection image on one surface; and efficient, compact electronic data storage media and techniques.

ACIC needs improved equipment and techniques to perform color separa-

tion and the related editing functions to satisfy chart production requirements economically and on a timely basis. When the color separation function

is automated, a digital step will be required. If the magnetic tapes (or whatever storage media is used) resulting from the Automated Color Separation System (ACSS) are saved, a library of ACIC products, in machin- able form, wiLl come about in time. This file will constitute the Automated Aeronautical Chart File (AACF). Thus, automation of the color separation function will Yield a secondary potential of further automation improve- ments in chart compilation and revision.

a. Significance. Color separation consumes a significant por-

tton of ACIC resources. The extent of this is shown in the following

generalization:

Significance of Automated Color Separation in Chart Production

Function

Per cent of Production Time Accession, store, select, retrieve source materials .. From 5% to 20%

Compilation of chart manuscript From 40% to 70%

COLOR SEPARATION•...••...•... From 20% to 30%

Lithographic Printing... 5%

Color separation consumes a significant segment of the calendar time required to produce a chart. Color separations for aeronautical charts require from 500 man-hours for each small chart up to 1,800 man- hours for each large chart.

should be noted that no other progress can be made on the production of a chart while color separation is under- way. On a PERT chart, for instance, color separation would stand alone

in the time sequence with no possible parallel functions taking place.

b. Characteristics. The color separation process is purely deterministic. The creative cartographic processes culminate in the base manuscript which is turned over to negative engravers for color separation. Our objective is to automate this function as nearly as possible.

(1) Cartographers compile manuscripts, making use of all available cartographic, photographic, and textual source materials.

All information is delineated on the manuscript to adjust the detail to the geodetic base. Relative positioning of features is assured.

Manuscript overlays are usually compiled for such things as geographical names, a.eronautical information, and relief.

(2) Color separation is begun by precisely copying the manu- scripts. These are printed on scribecoat material which can be engraved.

A scribecoat is made for each color to appear on the finished chart.

Each scribecoat is designated for a color, and a negative engraver traces out one color-category of detail on each scribecoat.

(3) After all scribecoats are engraved, they are used exactly as if they were color separation negatives. A composite of these is

printed, in color, on watercoat. This is a final review proof, used for edit and registration check before printing.

(4) The engraved scribecoats are then used to make the litho- graphic press plates. The chart colors are applied to the printed chart by inking the offset press rollers. One color is printed by each pass by an offset press cylinder.

c.

applied to

Capab;

icy. The Automated Color Separation System will be separati

colors on the base manuscript such as the following:

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hydrography, roads, railroads, rlams, bridges, populated places, power lines, boundaries, forts, vegetation, ridge liues, and so forth.

d. Anticipated Improvements. We are seeking a reduction of man-hours _re~uired for color separation on the order of 70%. This high order of improvement is expected to come about over a period of about four years. The first system, expected to be in operation in about two years, will probably yield an improvement of about 20%. As the Automated Aeronautical Chart File grows, giving ACIC a broad digital store of machin-

able data, extended potentials will be explored in on-line planimetric compilation.

CONCEPT

I t appears now that color separation can be relegated to electro- optical and computer functions eventually, eliminating many of the present

coscribecoatco, "peeLcoat '", and related photomechanical operations. This would entail:

a. Create master compilation sheet in colored pencils or inks.

b. Scan the compilation sheet, using filters to distinguish between colors.

c. Read the scanned information onto magnetic tape.

d. Introduce the magnetic tape into a general purpose computer for scale transformation, attenuation of signals to meet specified line weights, applying logic to signs and symbols, improving drafting, and production of the contrOL tape for the printer unit.

e. The tape produced by the computer would control an electro- optical printer which would expose the color-separation negative.

f. The color-separation negative would be contact-printed directly onto the offset press plate in the normal manner.

PI.ANNFCl CONJi'IGlJRATION

We are approaching color-separation automation in three phases.

Rome Air Development Center is developing the system in three progres- sively improved models, testing each one in their laboratory before forwarding it to ACIC. Descriptions of the three models follow:

a. Model I, Semi-automatic Color Separation System. The first equipment to be procured will consist of three components, a Semi-automatic Cartographic Re ader , a Cartographic Data Translator, and a Color Separa- tion Line Plotter. The source of' information is the base manuscript.

The extraction of the graphic data is based on combining the interpretive capabilities of a human operator Wic'l the accurate digitizing and rapid data processing capabilities of a'o,_'h'ine. The digitizing hardware is capable of collecting the data accurately and arranging it in the required Cartographic Data Translator format.

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SEMI-AUTOMATIC CARTOGRAPHIC

READER

CARTOGRAPHIC DATA TRANSLATOR

COLOR SEPARATION LINE PLOTTER

(1) The Semi-Automatic Cartographic Reader is of the line following type. This device will be used to digitize data describing any series of curves or lines traced by an operator on a graphic presen- tation. These may be open or closed contours, shorelines, highways, railroads, etc. The device also automatically measures and records the coordinates of individual points selected by the operator. These points may locate place names, spot elevations, fiducial marks, etc. Anyauxil-

iary information the operator may wish to add to describe each curve or point is automatically made part of the digital record.

The device will consist of two units; a specialized tracing table and a control and recording unit. The tracing table will be the operator's work station and will include a copy surface of a size designed for minimum operator fatigue and maximum work area. Depending on the optimum size of the work area, it may be necessary to trace the graphic in increments. A freely moving tracing arm with an electronic stylus and a keyboard for entering auxiliary information are part of the tracing table. Electronic impulses initiated by the stylus in its path movement are buf'f'erc st.ored to provide a means of accumulating infonnation at a rate determined by the operator and of transferring the information to tape in discrete blocks or records. As the operator traces, the buffer fills and when enough data for the record has been accumulated, the mag- netic recorder is started automatically and the buffer data is rapidly transferred to the tape. The buffer is capable of continuously accepting new data, even while previously filed data is being transferred to tape.

(2) The Cartographic Data Translator will, upon execution of specific built-in commands, produce magnetic tapes containing digital

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information pertaining to individuaJ. chart features such as roads.

I t is anticipated that, not only will we extract aJ.l information of a specific area, but also select the compilation specification data such as line weights. The outputs will be used to drive the Color Sepa- ration Line Plotter.

CARTOGRAPHIC DATA TRANSLATOR

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(3) The Color Separation Line Plotter provided in Model I will automaticaJ.ly provide a graphic plot of the Cartographic Data Trans- lator output, and!or from manually entered data. Coded decimaJ. and!or m.anually entered data will be translated to analog information in the Color Separation Line Plotter. This anaJ.og information will be used to drive a light projector ave,' a photographic media, by means of an

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(a) Have a moderate speed.

(b) Be driven from digital information stored on mag- netic tapes.

(c) llave a plotting accuracy of .!O.07uun.

(d) Control weight of lines in photographic mode.

(e) Select double, triple, or dashed lines according to direction from the magnetic tape.

(r)

Understandably, this is a very specialized plotter.

However, the state of the art has progressed to a pOint where the accu- racies and versatility required for this device can be provided.

COLOR SEPARATION LINE PLOTTER

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b. Model II, Automated Color Separation System. Model II will be an evolutionary increase in capability of ModelL The automation of the Cartographic Reader; the transformation of the data processing from the prot.ct.ype to the true data processing central; the introduction of soft- ware packages to increase the scope of color separation by introducing

scaling; feature selection according to chart scale; and the introduction of an on-line editing capability all lead to a system that lends itself to automation of compilation processes required in updating and recompila- tion of charts.

Semi-Automatic Automatic

Cartographic Cartographic

Reader Reader

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Cartographic Digital Storage

Data Device with

Translator Read/Write

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Cartographic Color

Editing Separation

Console Line Plotter

(1) The Cartographic Editing Console will be a multi-display device with an editing (data correction) capability. This will be a dynamic device with a multiple display on a single screen. The primary display

will be the compilation manuscript optically projected on the viewing surface with an electronic overlay of the digitized feature to be edited.

(a) Essentially, the device must display the basic manu- script, any associated drafted overlays, and also a digitally generated overlay of the feature being edited for accuracy, location, etc., and above all, a means for correcting any erroneous positioning, gaps, and/or digitizing infor- mation overlooked.

(b) Ideally, an optical-electronic display with a tablet stylus correction mode will optimize the editor's capabilities. The optical portion will be used to present the source or reference graphic on a viewing

surface; then electronically, the digitally stored new information will be presented as an overlay on the display. Finally, a third presentation will be made on the display surface pointing up corrections to be made in the digital store. The editor will, by depressing appropriate keyboard commands,

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indicate the end of a correction. Initial~y, the correction data will be placed into a buffer store and then later dumped into the appropriate record location to make the correction on the magnetic tape.

CARTOGRAPHIC EDITllfG CONSOLE

(2) The configuration of the Cartographic Data Translator module wU.l be considerably different from that used in Model I. However, once again the heart of this model will be available equipments.

(3) The Automatic Cartographic Reader will have a drum, which will hold manuscripts up to 50 x 60 inches. The manuscript drum will rotate under a reading head which will scan with a one-mil spot.

As an example, the maxinrum processing time for a 50 x 60 inch manuscript will be about ten hours. Employment of a special color discriminating

system will be employed to differentiate between the various colors existing on base manuscripts.

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(4)

an optimum ratio of' the system,

AUTOMATIC CARTOGRAPHIC READER

It will be possible to add readers and plotters to realize of' input and output devices to fully realize the potential

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Semi-Automatic Automatic

Cartographic , Cartographic

Reader Reader

Car-t.ogz-aphf.c Digital Storage

Data ,

Device

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with Read/Write

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Cartographic Color

Editing Separation

Console Line Plotter

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c. Model III

Automated Aeronautical Chart F'ile AACF. Model III ACSS-AACF will offer second and third generation mechanical improvements in the equipments described above. A Planimetric Compi1ation Conso1e wi11 be added Which will actrual.Ly be an improved Cartographic Editing Console. The Cartographic Director Module will be integrated with the Cartographic Data Translator, implementing a time-sharing system with special software for optimizing the data handling. This advanced model wil1 incorporate a considerable amount of computer programming and improved utilization of the system's special purpose computer.

PLANIMETRIC COMPILATION CONSOLE

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Automatic Semi-Automatic

Cartographic _'I Cartographic

Reader Reader

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Cartographic Cartographic Digital

Director _{I '}

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Module Translator Device wit^l:

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Cartographic Planimetric Color Editing Compilation Separation

Console Console Line Plotter

(1) I t will be possible to add additional input and output devices to this Model III ACSS-AACF to attain optimum productivity. The major improve- ment in ttlis time period will be the development of the digital data base.

(2)

Automated color separation will require some form of car-to- storage. A library of this digital data will constitute

AUTOMATED COLOE SEPARATION REQUIRES

CARTOGRAPHIC DIGITAL TRANSLATION

r,IJ1HI\HY OF DIGITAL CARTOGRAPHIC DATA CONSTITUTES

AUTO!-'1J\.TED AERONAUTICAL CHART FILE

(3) An Automated Aer-onauri.ca.L Chart File (MCF) will bring about the capability of doing planimetric r-evIs i.on and recompilation on line.

The cartographer will cause tile' "I'.1Tt to be displayed, he will cause source material to be superimposed on it, and make corrections directly on the electronic display with available controls. Such a system would materially improve color separation, allowing last-minute corrections and revisions, taking advarrtage of new sour-ce material.

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(1.1) An optimum l,'lo,lclIII f,,)n:~tem is c xpe ct ec to look something like that shown in the Fol Lowl nz

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Semi-Automatic

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Cartographic

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Reader Reader _f-

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Cartographic

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D'ir-e ct.or Data fo- Storage Device

Module I Translator with Read/Write

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Cartographi Planimetric Color Editing Compilation Separation Console Console Line Plotter

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(5) These equipments will be added, as developments take place building this optimum system. It follows the evolutionary idea.

Present ltJork

Rome Air Development Center has let two contracts for work on automatic color separation. A third contract is closely related and directed toward automatic planimetric ^cornpi.Le.ti on, In conjunction with these efforts, ACIC has employed a high-level con suLt.ant, to rigorously derive mathematical models covering aspects to be considered for aut.omat.ion ,

Due to the early state of these efforts, nothing can be reported with respect to contractual progress at this time. By the

1967

Conclusions

Our investigations at this point show that gains will be realized in four ways: cost reduction, improved qua.l.i.t.y control, reduced calendar time, and quick response.

a.

obvious related will be

Cost Reduction. If manhours are saved in color separation, it is that savings in product ion cost "ill be realized. Also, costs to supervisory manpower, trainirJg, editing, and production control reduced.

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b. Quality Control. Automation is inherently a rigorous disciplinarian when it comes to procedures and specifications. This aspect will force

uniformity and conformance. This is a necessary condition in color separation, in that

is purely a deterministic function. The negative engraver is not allowed to exercise any cartographic license. Fine control will be exercised over line weights, avoiding present dependence on manual gauging. Relegating this function to mechanical means will in itself improve quality for the following reasons:

(1) The machine will permanently store specifications, whereas human memories sometimes fail.

(2) The very long manual process, with changing engravers due to illness, leave, and priority interruptions, cause varying quality. The automated system would be unaffected by changing operators or interruptions.

c. Reduce Calendar Time. By reducing the calendar time for color separation, charts will be more up-to-date when distributed. Once chart compilation ends and color separation begins, there is no further opportunity to economically make revisions. The present length of time required for color separation creates technical problems such as:

(1) Degradation due to handling in work and overnight storage.

(2) Passing instructions on to different work shifts.

(3)

Registration and dimensional changes due to temperature and relative humidity changes.

d. Quick Response. We believe that when the above three gains are realized, then quick response to sudden chart requirements will follow readily •

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