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  • The reason for the large variations in reports of what level constitutes a JND in object colors stems from the fact that visual threshold depends on more than just the color difference The CIE94 and CMC equations also contain variables for parametric effects such as surface texture illuminance level separation between color specimens surrounds backgrounds etc My PhD specimens and the CMC and CIE94 experiments were performed on neutral gray backgrounds and surrounds with illuminance levels of more than 1000 lux The specimens subtended at least a 10 degree visual angle the CMC specimens were threads wound on a card my specimens and those of CIE94 were automotive paints on flat smooth substrates Work reported by Tennessee Eastman on polypropylene plastic sheeting pebble grained for automotive interiors required parametric factors similar to the CMC equation but with a tolerance level of 0 4 instead of the 1 0 used in textile evaluations That implies that for textured plastics 0 4 CMC is still above the JND level If I were to change the separation of the specimens from just touching side by side to a 10 degree separation over under then the tolerances would be much larger How much larger I don t really know There are some guidelines in a CIE report but I do not remember the specifics Sally needs to define the viewing space more carefully before we can begin to guess a minimum perceptable color difference One intention of the L a b formulation is that when you calculate delta E sqrt delta L 2 delta a 2 delta b 2 a delta E 1 should be just barely percievable to some viewers If you want most people to be able to distinguish between two colors most of the time a delta E 3 is needed

    Original URL path: http://www.efg2.com/Lab/Library/UseNet/1999/1004.txt (2016-02-14)
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  • at 5 nm intervals It appears that it s nowhere available at the web in contrast to Illuminants A and D65 Thanks in advance Harro Stokman Here is Illuminant C normalized so that the maximum irradiance is 100 320 0 0 0080 325 0 0 1612 330 0 0 3224 335 0 1 2491 340 0 2 1759 345 0 3 9084 350 0 5 6411 355 0 8 0184 360 0 10 3957 365 0 13 8609 370 0 17 2455 375 0 22 1614 380 0 26 5936 385 0 32 1702 390 0 38 1981 395 0 44 4596 400 0 51 0114 405 0 57 8693 410 0 64 9529 415 0 72 1493 420 0 79 0555 425 0 85 2606 430 0 90 5793 435 0 94 8908 440 0 97 9127 445 0 99 4842 450 0 99 9274 455 0 99 6050 460 0 99 2022 465 0 99 3634 470 0 99 7662 475 0 100 0000 480 0 99 8468 485 0 99 0571 490 0 97 2681 495 0 94 2057 500 0 90 3377 505 0 86 2116 510 0 82 4401 515 0 79 6277 520 0 78 0884 525 0 77 9918 530 0 78 9749 535 0 80 5383 540 0 82 2790 545 0 83 7698 550 0 84 7772 555 0 85 1558 560 0 84 8578 565 0 83 8987 570 0 82 4401 575 0 80 7076 580 0 78 8137 585 0 76 9038 590 0 75 1067 595 0 73 5112 600 0 72 2863 605 0 71 5851 610 0 71 2386 615 0 71 0694 620 0 70 9968 625 0 70 9646 630 0 70 9162 635 0 70 8034 640 0 70 7550 645 0

    Original URL path: http://www.efg2.com/Lab/Library/UseNet/1998/0701a.txt (2016-02-14)
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  • Y dimension In X Y Z space it is the polyhedron defined by these eight points white cyan magenta yellow red magenta yellow blue cyan magenta green cyan yellow and black cyan magenta yellow You may also use x y Y space If you plot cyan blue magenta red yellow and green on the x y chromaticity diagram you will have a projection of the gamut on that plane Steve

    Original URL path: http://www.efg2.com/Lab/Library/UseNet/1999/0928.txt (2016-02-14)
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  • mailing list send no junk mail NNTP Posting Date Thu 15 Jul 1999 08 34 48 PDT Newsgroups sci engr color In article fotodave aol com FotoDave wrote Is there a simple equation or equations to convert reflective density from a densitometer to lightness CIE L For density D in the range 0 to 2 Lstar 116 power 10 D 3 16 That is take one third of the density

    Original URL path: http://www.efg2.com/Lab/Library/UseNet/1999/0715.txt (2016-02-14)
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  • 1999 08 58 32 PDT Newsgroups sci engr color In article Frank Wood wrote I ve been playing around in this field for thirty five years and today s the first time I ve seen the terms reflective density Reflective density is common enough see article by fotodave aol com or lightness I infer that lightness means luminance No not at all Lightness also known as L pronounced EL star is the the CIE s perceptually uniform scale for luminance L is roughly luminance to the 0 4 power The exponent 1 3 appears in the definition of L but a scaling and an offset make the overall power function behave more like 0 4 And density in my book means nothing other than the logarithm of the transmission to base 10 The negative indicator on your calculator must be broken You can define transmission density as the negative of base 10 log of transmittance or as the base 10 log of the reciprocal of transmittance Both definitions are equivalent Densitometers measure the transmission of a substance usually a processed photographic film and often in logarithmic units And NOTHING else There are reflection densitometers they measure reflectance Densitometers do not

    Original URL path: http://www.efg2.com/Lab/Library/UseNet/1999/0716d.txt (2016-02-14)
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  • printers I really didn t study why bsClear worked they way it did I should have You have an eagle eye and mind to catch this problem Finally I looked into graphics pas and saw that setting the color for the brush sets brush style to bsSolid if the style was previously bsClear Then what you endly get is not bsClear but bsSolid which explains that you get the same two first rows I didn t understand exactly what you were saying until I studied the code you described This short example shows the difference Why does Brush Style bsClear behave differently if Brush Color is set before or after This behavior appears to date back to D1 procedure TFormBSenigma ButtonDrawRectsClick Sender TObject VAR Bitmap TBitmap brush WORD y WORD begin Bitmap TBitmap Create TRY Bitmap Width Image1 Width Bitmap Height Image1 Height FOR brush 0 TO 7 DO wrong bsClear behavior here BEGIN Bitmap Canvas Brush Style TBrushStyle brush Bitmap Canvas Brush Color clRed y 5 brush 20 Bitmap Canvas Rectangle 5 y 5 20 y 20 END FOR brush 0 TO 7 DO expected bsClear behavior BEGIN Bitmap Canvas Brush Color clRed Bitmap Canvas Brush Style TBrushStyle brush

    Original URL path: http://www.efg2.com/Lab/Library/UseNet/2001/0305a.txt (2016-02-14)
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  • cut piece is returned by the function and is deleted from the original string Parameters Canvas The canvas on which the text is to be drawn used to calculate width Text The text to cut MaxWidth The maximum width of the cut out text Return Value The text that has been cut out from the string function CutString Canvas TCanvas var Text String MaxWidth Integer String var UseStr TestStr HyphStr String NextWord String i Integer HyphenWidth Integer Stop Boolean begin UseStr NextWord Text Trim Text Stop False Concatenate new words repeat UseStr UseStr NextWord Delete Text 1 Length NextWord Remove the word we have picked out from the text NextWord GetNextWord Text If we took a word that s followed by a hard return then we should break at this line i 1 while i MaxWidth or NextWord Hyphenate the word if it is too long to be written if UseStr then begin HyphenWidth Canvas TextWidth HyphStr TestStr i 0 while Canvas TextWidth TestStr then UseStr HyphStr Delete Text 1 Length HyphStr end Result UseStr end Prints text in a circular shape Parameters TextToPrint The text to be printed in the circle Canvas The canvas where the text should be drawn Center The centre of the circle in which the text should be drawn Diameter The diameter of the circle in which the text should be drawn Options A few options that modify the way the text is printed Return Value The number of characters that actually were printed in the circle If the circle is big enough to hold the full string then this value will be equal to Length TextToPrint If not it will indicate how many characters of the string there was room to print If nothing was printed then it will return 0 function PrintTextInCircle TextToPrint

    Original URL path: http://www.efg2.com/Lab/Graphics/JosefGarviWrappingText.txt (2016-02-14)
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  • created Returns true if file exists false on error Var WaitHandle THandle begin Result False Let s assumed we failed WaitHandle FindFirstChangeNotification PChar ExtractFilePath FileName False FILE NOTIFY CHANGE FILE NAME If INVALID HANDLE VALUE WaitHandle then begin The path to the file does not exists Exit end repeat if WaitForSingleObject WaitHandle INFINITE WAIT OBJECT 0 then begin something happenned in the directory if FileExists FileName then begin result True

    Original URL path: http://www.efg2.com/Lab/Library/UseNet/2000/1105.txt (2016-02-14)
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