Cs4 converting to grayscale

Question

Hello all, I have a document in CMYK color and im having trouble converting it's swatches to grayscale. I did a search and it only yielded Grayscale converstion at the PDF level. However the Grayscale color space seems to have been removed from the options available in the PDF maker dialogue box. Anyone have some suggestions? Thanks!

Answer 1

Sure. I have been thinking for a while it could be useful -- after all, it is an option in Illustrator. (But then we've known for years now that the programmers of InDesign Do Not Talk to the ones of Illustrator. I bet there is a Movie of the Week in that story...)
This extremely quick-and-dirty script converts a swatch of choice to Lab color, then uses the L component for the Black part in a CMYK color. It should also be possible to convert it to a tint of black, but that's just a bit more work.
(Copy, paste into Adobe's ESTK Editor, save as "SwatchToGray.jsx" into your User Scripts folder. Only works with simple RGB, Lab, or CMYK swatches; not with gradients, tints, Pantones, imported colors, mixed ink groups, or anything else that's not a simple swatch.)
//DESCRIPTION:Convert a color swatch to grayscale
// Jongware, 13-Jul-2010
var myDialog = app.dialogs.add({name:"Swatch To Gray", canCancel:true});
swatchlist = [];
namelist = [];
for (i=4; i<app.activeDocument.swatches.length; i++)
if (!(app.activeDocument.swatches[i].hasOwnProperty("baseColor") || app.activeDocument.swatches[i].hasOwnProperty("gradientStops")))
  swatchlist.push(app.activeDocument.swatches[i]);
  namelist.push(app.activeDocument.swatches[i].name);
with (myDialog)
with (dialogColumns.add())
  with (dialogRows.add())
   staticTexts.add ({staticLabel:"Swatch"});
   swatchDropDown = dropdowns.add ({stringList:namelist, selectedIndex:0});
if (myDialog.show())
// Fetch selection
swatch = swatchlist[swatchDropDown.selectedIndex];
// Convert to RGB:
swatch.space = ColorSpace.LAB;
// Make quick-and-dirty gray
gray = swatch.colorValue[0];
// Convert to CMYK
swatch.space = ColorSpace.CMYK;
// Set color
swatch.colorValue = [0,0,0, 100-gray];