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Updating the contrast value #1780

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Merged
merged 5 commits into from
Jun 10, 2021
Merged

Updating the contrast value #1780

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b96c69b
Updating the contrast value
alastc May 4, 2021
a5b25bf
Rain's suggested wording
alastc May 11, 2021
e828fad
removing the SRGB reference
alastc May 11, 2021
1fa788a
Meeting updates.
alastc May 11, 2021
fce0993
Aligned understandings docs
alastc May 13, 2021
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12 changes: 0 additions & 12 deletions biblio.js
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Original file line number Diff line number Diff line change
Expand Up @@ -31,18 +31,6 @@ respecConfig.localBiblio = {
"publisher": "International Standards Organization"
},

"sRGB": {
"authors": [
"M. Stokes",
"M. Anderson",
"S. Chandrasekar",
"R. Motta"
],
"date": "November 5, 1996",
"href": "https://www.w3.org/Graphics/Color/sRGB.html",
"title": "A Standard Default Color Space for the Internet - sRGB, Version 1.10"
},

"UNESCO": {
"date": "1997",
"href": "http://www.unesco.org/education/information/nfsunesco/doc/isced_1997.htm",
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10 changes: 6 additions & 4 deletions guidelines/terms/20/relative-luminance.html
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Expand Up @@ -12,13 +12,13 @@


  • if RsRGB <= 0.03928 then R = RsRGB/12.92 else R = ((RsRGB+0.055)/1.055) ^ 2.4
    		•
  • if RsRGB <= 0.04045 then R = RsRGB/12.92 else R = ((RsRGB+0.055)/1.055) ^ 2.4
    		•

  • if GsRGB <= 0.03928 then G = GsRGB/12.92 else G = ((GsRGB+0.055)/1.055) ^ 2.4
    		•
  • if GsRGB <= 0.04045 then G = GsRGB/12.92 else G = ((GsRGB+0.055)/1.055) ^ 2.4
    		•

  • if BsRGB <= 0.03928 then B = BsRGB/12.92 else B = ((BsRGB+0.055)/1.055) ^ 2.4
    		•
  • if BsRGB <= 0.04045 then B = BsRGB/12.92 else B = ((BsRGB+0.055)/1.055) ^ 2.4
    		•

    Expand All @@ -35,11 +35,13 @@


    The "^" character is the exponentiation operator. (Formula taken from [[sRGB]] and

    The "^" character is the exponentiation operator. (Formula taken from

    [[IEC-4WD]]).



    Before May 2021 the value of 0.04045 in the definition was different (0.03928). It was taken from an older version of the specification and has been updated. It has no practical effect on the calculations in the context of these guidelines.

    Almost all systems used today to view Web content assume sRGB encoding. Unless it
    is known that another color space will be used to process and display the content,
    Expand Down
    7 changes: 4 additions & 3 deletions techniques/general/G145.html
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    Original file line number Diff line number Diff line change
    Expand Up @@ -52,7 +52,7 @@
    • if R
      		•
      sRGB
      <= 0.03928 then
      <= 0.04045 then
      R
      = R
      sRGB
      Expand All @@ -63,7 +63,7 @@
      +0.055)/1.055) ^ 2.4
    • if G
      		•
      sRGB
      <= 0.03928 then
      <= 0.04045 then
      G
      = G
      sRGB
      Expand All @@ -74,7 +74,7 @@
      +0.055)/1.055) ^ 2.4
    • if B
      		•
      sRGB
      <= 0.03928 then
      <= 0.04045 then
      B
      = B
      sRGB
      Expand Down Expand Up @@ -146,6 +146,7 @@
    • #4 is true
      		•

      Before May 2021 the value of 0.04045 in the definition was different (0.03928). It was taken from an older version of the specification and has been updated. It has no practical effect on the calculations in the context of these guidelines.

      Resources

        Expand Down
        7 changes: 4 additions & 3 deletions techniques/general/G17.html
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        Original file line number Diff line number Diff line change
        Expand Up @@ -53,7 +53,7 @@
        • if R
          		•
          sRGB
          <= 0.03928 then
          <= 0.04045 then
          R
          = R
          sRGB
          Expand All @@ -64,7 +64,7 @@
          +0.055)/1.055) ^ 2.4
        • if G
          		•
          sRGB
          <= 0.03928 then
          <= 0.04045 then
          G
          = G
          sRGB
          Expand All @@ -75,7 +75,7 @@
          +0.055)/1.055) ^ 2.4
        • if B
          		•
          sRGB
          <= 0.03928 then
          <= 0.04045 then
          B
          = B
          sRGB
          Expand Down Expand Up @@ -147,6 +147,7 @@
        • #4 is true
          		•

          Before May 2021 the value of 0.04045 in the definition was different (0.03928). It was taken from an older version of the specification and has been updated. It has no practical effect on the calculations in the context of these guidelines.
        • G148
          		•
        • G174
          		•
          Expand Down
          7 changes: 4 additions & 3 deletions techniques/general/G18.html
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          Original file line number Diff line number Diff line change
          Expand Up @@ -58,7 +58,7 @@
          • if R
            		•
            sRGB
            <= 0.03928 then
            <= 0.04045 then
            R
            = R
            sRGB
            Expand All @@ -69,7 +69,7 @@
            +0.055)/1.055) ^ 2.4
          • if G
            		•
            sRGB
            <= 0.03928 then
            <= 0.04045 then
            G
            = G
            sRGB
            Expand All @@ -80,7 +80,7 @@
            +0.055)/1.055) ^ 2.4
          • if B
            		•
            sRGB
            <= 0.03928 then
            <= 0.04045 then
            B
            = B
            sRGB
            Expand Down Expand Up @@ -152,6 +152,7 @@
          • #4 is true.
            		•

            Before May 2021 the value of 0.04045 in the definition was different (0.03928). It was taken from an older version of the specification and has been updated. It has no practical effect on the calculations in the context of these guidelines.

            Resources

              Expand Down
              4 changes: 2 additions & 2 deletions understanding/20/contrast-enhanced.html
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              Original file line number Diff line number Diff line change
              Expand Up @@ -163,13 +163,13 @@

              Rationale for the Ratios Chosen

              Notes on formula

              Conversion from nonlinear to linear RGB values is based on IEC/4WD 61966-2-1 [[IEC-4WD]] and on "A Standard Default Color Space for the Internet - sRGB" [[sRGB]].

              Conversion from nonlinear to linear RGB values is based on IEC/4WD 61966-2-1 [[IEC-4WD]].

              The formula (L1/L2) for contrast is based on [[ISO-9241-3]] and [[ANSI-HFES-100-1988]] standards.

              The ANSI/HFS 100-1988 standard calls for the contribution from ambient light to be
              included in the calculation of L1 and L2. The .05 value used is based on Typical Viewing
              Flare from [[IEC-4WD]] and the [[sRGB]] paper by M. Stokes et al.
              Flare from [[IEC-4WD]].


              This Success Criterion and its definitions use the terms "contrast ratio" and "relative
              Expand Down
              4 changes: 2 additions & 2 deletions understanding/20/contrast-minimum.html
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              Original file line number Diff line number Diff line change
              Expand Up @@ -223,13 +223,13 @@

              Rationale for the Ratios Chosen

              Notes on formula

              Conversion from nonlinear to linear RGB values is based on IEC/4WD 61966-2-1 [[IEC-4WD]] and on "A Standard Default Color Space for the Internet - sRGB" [[sRGB]].

              Conversion from nonlinear to linear RGB values is based on IEC/4WD 61966-2-1 [[IEC-4WD]].

              The formula (L1/L2) for contrast is based on [[ISO-9241-3]] and [[ANSI-HFES-100-1988]] standards.

              The ANSI/HFS 100-1988 standard calls for the contribution from ambient light to be
              included in the calculation of L1 and L2. The .05 value used is based on Typical Viewing
              Flare from [[IEC-4WD]] and the [[sRGB]] paper by M. Stokes et al.
              Flare from [[IEC-4WD]].


              This Success Criterion and its definitions use the terms "contrast ratio" and "relative
              Expand Down