1、INTERNATIONAL TELECOMMUNICATION UNION ITU-T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU T.23 (04/94) TELEMATIC SERVICES TERMINAL EQUIPMENTS AND PROTOCOLS FOR TELEMATIC SERVICES STANDARDIZED COLOUR TEST CHART FOR DOCUMENT FACSIMILE TRANSMISSIONS ITU-T Recommendation T.23 (Previously “CCIlT Recomm
2、endation”) _ STD-ITU-T RECMN T.23-ENGL 1774 48b257L Ob20035 4b2 M FOREWORD The ITU-T (Telecommunication Standardization Sector) is a permanent organ of the International Telecommunication Union (ITU). The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recomme
3、n- dations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topi
4、cs. The approval of Recommendations by the Members of the IT-T is covered by the procedure laid down in WTSC Resolution No. 1 (Helsinki, March 1-12, 1993). IT-T Recommendation T.23 was prepared by ITU-T Study Group 8 (1993-1996) and was approved under the WTSC Resolution No. 1 procedure on the 7 Apr
5、il 1994. NOTE In this Recommendation, the expression “Administration” is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. O ITU 1994 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means,
6、electronic or mechanical, including photocopying and microfilm, without permission in writing from the IT. CONTENTS Annex A . Description of the standardized facsimile colour test chart A.l Dimensions of the test ch art A.2 Test Chart 6 - 4-Colour Printing Facsimile Test Chart 4CPO1 A.2.1 Pattern 1
7、- ITU-T border of four scales with inch and millimetre markings A.2.2 Pattern 2 - Black bar across full page width and a scale in inches across the top A.2.3 Pattern 3 - Gurley type Pestrecov Star pattern with circles of 50, 100 and 200 lines per 25.4 mm . A.2.4 A.2.5 Pattern 5 - Colour patches, tex
8、t and line patterns . A.2.6 Pattern 6 -Text . A.2.7 Pattern 7 - Solid colour blocks . A.2.8 A.2.9 Pattern 9 - Screened grey scales . A.2.10 Pattern 10 - Photograph A.2.11 Pattern 1 1 - Computer-generated image A.2.12 Pattern 12 - Magazine cover A.2.13 Pattern 13 - CMY grey scale Pattern 4 - Colour p
9、atches Pattern 8 - Eighteen colour patches Page 1 1 1 4 4 4 4 4 4 4 6 6 6 6 7 7 Recommendation T.23 (W94) 1 SUMMARY This Recommendation defines the high resolution colour test chart. Included is a biacklwhite photocopy of the latest revision of the colour chart (the colour chart is available from IT
10、 Sales Department). This full-colour chart was printed from 4-colour separation negatives in order to provide low cost colour reproduction. The chart includes a Pestrecov Star, various line patterns and colour patches, text, solid colour blocks, screened grey scales, a colour photograph and two comp
11、uter-generated images. The purpose of the chart is to satisfy colour testing requirements that cannot be adequately met with current test charts. The chart can be used with electronic document storage facilities, electronic document transmission facilities, and facsimile apparatus. Recommendation T.
12、23 (W4) iii STANDARDIZED COLOUR TEST CHART FOR DOCUMENT FACSIMILE TRANSMISSIONS (Geneva, 1994) The ITU-T, considering (a) that a standardized colour test chart to check the quality of document facsimile transmissions will have great advantages. The advancing technology of document facsimile has brou
13、ght forth colour testing requirements that cannot be adequately met with current test charts. New higher resolution needs and transmission of high quality colour imagery must be taken into consideration: (b) evaluating the technical quality of the page and the legibility of the text, that the requir
14、ement for low cost colour reproduction has led to the definition of a new colour test chart for unanimously adopts the view (1) ITU-T standardized test chart; that tests of document facsimile transmission quality should be carried out in the international service using the (2) ITU. The chart is desc
15、ribed in Annex A; the specimen printed in Annex A cannot be used for measurements; that the test chart should be produced under the supervision of the ITU-T and should be offered for sale by the (3) facilities, and facsimile apparatus in accordance with appropriate ITU-T T-Series Recommendations. th
16、at the chart should be used with electronic document storage facilities, electronic document transmission Annex A Description of the standardized facsimile colour test chart (This annex forms an integral part of this Recommendation) A.l Dimensions of the test chart - length: 302 mm, - width: 222 mm.
17、 It is divided into subclauses marked A.2.1 to A.2.13. These subclauses markings are also used to designate the following clause and subclauses which describe the given clause. A.2 Test Chart 6 - 4-Colour Printing Facsimile Test Chart 4CP01 This full-colour chart was printed from 4-colour separation
18、 negatives. (See Figure A.l for a black and white copy of the chart.) Some of the patterns are the same as Test Chart No. 4 (blacklwhite test chart), or modifications thereof to print with colour primaries rather than black. The overall size of the printed chart is 222 x 302 mm (8 3/4 x 11 7/8 inche
19、s) to allow for maximum paper size tolerances. Recommendation T.23 (04/94) 1 - STD-ITU-T RECMN T-23-ENGL L99Li 48b2571 Ob20037 O08 ITUTIMES cc/m ROLE The CCITT will romote the , /II development of technical facilities an8 their most efficient operation with a view to improving the i I 1 efficiency o
20、f telecommunication services, increasing E their usefulness and making them as far as possible, )i I I generally available to the public. i- 2 ILE TEST CHART 4CP01 ITU-TEScHAK“o6 - -“i.I -:1rry 1 “1; 11 - FIGURE A. 1l.23 4-Coiour Printing Facsimile Test Chart 4CP01 (The colour chart is available fro
21、m ITU Sales Service.) Recommendation T.23 (04/94) Pattern descriptions The overall size of the printed chart is 222 x 302 mm. The patterns that make up the chart are defined below. Refer to the corresponding numbers on the Test Chart No. 6 pattern arrangement (see Figure A.2). CI 1 3 4 5 6 7 8 9 10
22、12 FIGURE A.UT.23 Pattern arrangement Recommendation T.23 (04/94) 3 A.2.1 Pattern 1 - ITU-T border of four scales with inch and millimetre markings A border consisting of four scales with millimetre markings, one scale per side. On the scales. the 5 and 10 mm lines are extended. The red mows at the
23、top of the chart are 8 1/2 inches apart. The top border is red (solid magenta and yellow printing). The right border is green (solid yellow and cyan printing). The left border, also marked in inches, is blue (solid cyan and magenta printing). The bottom border consists of three differently coloured
24、segments. Its colours are, from left to right, cyan, magenta and yellow. A.2.2 Pattern 2 - Black bar across full page width and a scale in inches across the top A black bar at the top of the chart. The bar starts on the left chart edge and ends on the right chart edge. There is a red scale under it.
25、 This scale is in inches. It starts with O in the middle of the page and has .1” scale markings. Inch markings are slightly extended and are labelled. A.2.3 Pattern 3 - Gurley type Pestrecov Star pattern with circles of 50,100 and 200 lines per 25.4 mm A Gurley type Pestrecov Star of solid, non-scre
26、ened, tapered-width lines with three solid-white concentric circles. The pattern is divided into four segments. Clockwise from left, the patterns are cyan, magenta, yellow, and black. The circles, from the outermost to the innermost, have line widths of 50, 100, and 100 pelshnch, respectively. The p
27、attern is printed at full contrast, with the colour line width the same as the white spaces between lines. A.2.4 Pattern 4 - Colour patches Eighteen colours with eight intensities for each colour, for a total of 144 different colour patches. The printing colour primary magenta is row A (left half).
28、Yellow is row G (left half). Cyan is row M (right half). Of the two-colour primaries, red (magenta and yellow) is row D (left half). Green is row J (right half). Blue is row P (right half). Each row between the primaries has a fixed ratio of two printing primaries as the screen dot percentages decre
29、ase in steps. Column 8 of each set has 25 per cent black added to the printing ink combinations of column 3 to give warmer tones. The screen ruling is 175 linedinch. Table A.l shows the colour combinations of each colour patch in per cent screen dot density. A.2.5 Pattern 5 - Colour patches, text an
30、d lime patterns Twelve light colour patches selected from the Macbeth colour chart, plus text and isolated line patterns in the same colour. The patches, text, and line patterns (see Figure A.3) are organized from left to right, respectively. The line patterns have line widths of .04, .O1 and .O05 i
31、nches (1.016, .254 and .127 mm). Half of the lines are slanted 1 in 10 to provide random matches between the scanning line sample and the pattern. The texts typeface edges provide a similar function. Kanji characters from the BWOl Test Chart substitute for the “QWERTY” in lines 9 through 12. The scr
32、een ruling is 175 linedinch. A.2.6 Pattern 6 - Text Black text that simulates magazine text that might be on the same page as a screened colour photo. The text consists of four postscript fonts: headline - Bookman .40” bold, heading - Helvetica -18”. first paragraph - New Century Schoolbook .13”, an
33、d the footnote - Helvetica Narrow .09”. The note is repeated in four point type and two point type. The second paragraph consists of characters of the Ming Dynasty in point sizes 10.5 and 7.875. A.2.7 Pattern 7 - Solid colour blocks Seven solid unscreened blocks of printing ink colours. These are so
34、lid patches of the primary printing ink colours, two- colour combinations, plus black. Starting at the left, the colours are cyan, magenta, yellow, red (magenta and yellow), green (yellow and cyan), blue (cyan and magenta), and black. 4 Recommendation T.23 (04) STD.ITU-T RECMN T.23-ENGL 1994 m 48b25
35、91 Ob200Ll2 bT2 ROW MM Y TABLE A.lR.23 1 2 3 4 5 6 7 8 BLACK 100 75 50 30 20 12 8 50 25 00000000 Cdour combinations (screen dot density in percent) BM Y CM Y COLUMN - 100 75 50 30 20 12 8 50 25 33 25 17 10 6 4 3 16 100 75 50 20 20 12 8 50 25 67 50 33 20 13 8 5 33 DM Y EM Y 100 75 50 30 20 12 8 50 25
36、 100 75 50 30 20 12 8 50 67 50 33 20 13 8 5 33 25 100 75 50 30 20 12 8 50 FM Y G M/C Y 33 25 17 10 6 4 3 16 25 100 75 50 30 20 12 8 50 00000000 25 100 75 50 30 20 12 8 50 HC Y I C Y 33 25 17 10 6 4 3 16 25 100 75 50 30 20 12 8 50 67 50 33 20 13 8 5 33 25 100 75 50 30 20 12 8 50 J C Y KC Y 100 75 50
37、30 20 12 8 50 25 100 75 50 30 20 12 8 50 100 75 50 30 20 12 8 50 25 67 50 33 20 13 8 5 33 LC Y MC MN 7 100 75 50 30 20 12 8 50 25 33 25 17 10 6 4 3 16 100 75 50 30 20 12 8 50 25 O O O O O O O0 Recommendation T.23 (04194) NC M oc M 5 100 75 50 30 20 12 8 50 25 33 25 17 10 6 4 3 16 100 75 50 30 20 12
38、8 50 25 67 50 33 20 13 8 5 33 PC M QC M 100 75 50 30 20 12 8 50 25 100 75 50 30 20 12 8 50 67 50 33 20 13 8 5 33 25 100 75 50 30 20 12 8 50 RC M 33 25 17 10 6 4 3 16 25 100 75 50 30 20 12 8 50 STD*ITU-T RECMN T.23-ENGL 1774 48b2571 Ob200Y3 537 0- 0.2 - 0.4 - Pattern 5 -une Portion 51 Enlargement sca
39、le 0 0.2 0.4 0.6 0.8 1 .o 1.2 1.4 1.6 ET-B Inches , I Slant: 1 horizontal pei for 10 EeiClcal peis H- V1 Line Widths (i 5%) Cobw 3 A = 0.04 in B = 0.01 in C = 0.005 in FIGURE A.31T.23 Line enlargement A.2.8 Pattern 8 - Eighteen dour patches Eighteen colour patches that combine black and each of the
40、printing colour primaries. These patches show colours not covered elsewhere in the chart. The first row of six patches uses the cyan primary. The second row uses magenta, and the bottom row uses yellow. These patches were chosen to give good steps to the eye. The left three patches of each row are 1
41、00 per cent primary overprinted by 60,40, and 20 per cent black dots from left to right, respectively. The next three patches are primaryhlack combinations of 60/20,40/20 and 20/20 per cent dots. The screen ruling is 175 linedinch. A.2.9 Pattern 9 - Screened grey des Three rows of screened grey scal
42、es consisting of patches with 90, 75, 50, 25, 10 and 5 per cent dots. The first row is 85 line screen. The second row is 175 and the bottom row is 133 line screen. A.2.10 Pattern 10 - Photograph A photograph. called Toys, that has a 175 line screen. It shows higher sharpness for fine detail in the s
43、tuffed animals and the faces, and provides a range of textures and patterns. Compare the fuzziness of the stuffed animals to repetitiveness of the blinds to the colour combinations present in the mans shirt. The presence of both bright and pastel colours provide widespread variations in luminance, h
44、ue and saturation. In addition, the image is rich in slowly varying coiour textures mixed with sharp colour boundaries. For example, note the slowly varying pink of the panthers leg next to the plaid of the girls skirt. A.2.11 Pattern 11 - Computer-generated image A computer generated simulation of
45、spheres with shadings for a 3dimensional effect. It shows various-sized differently- coloured spheres on a black background. Its 85 line screen represents the low end of colour photos in publications like business magazines. Plus, it provides a wide range of colour shadings with distinct edges. In g
46、eneral, each sphere is one colour, shaded to give a three dimensional appearance. The gradual transition in,colour of each spheres shading provides an excellent medium for discerning possible contouring effects. If contouring is present, it will usually manifest itself as a series of concentric circ
47、les with slightly different colours. The spheres edges also provide sharp boundaries against both the black background and other spheres. 6 Recommendation T.23 (04/94) A.2.12 A graphics image from a magazine cover that has a 150 line screen and exhibits a 3-dimensional effect. It uses pastel colours
48、 to denote surfaces and fine black lines to enhance details. It contains a number of repetitive patterns coupled with sharp boundaries between various colours. The white background contains many very small isolated and clumped dots of each primary printing colour. Many of these dots are smaller than
49、 those used in standard printing processes, providing an additional test target. Pattern 12 - Magazine cover A.2.13 Following the title, a 5-step CMY grey scale that may be used to check colour balance of the printing inks. Pattern 13 - CMY grey scale Recommendation T.23 (04/94) 7 STD-ITU-T RECMN T.23-ENGL 1774 W 48b2571 Ob20045 301 Printed in Switzerland Geneva, 1994
