Thursday, February 21, 2008

Adding a Splash of Color

Have you ever needed to add a splash of color to your otherwise black and white drawing?

Let's say that you have a plan drawing that plots using a CTB pen table where all the layer colors are mapped to black pens, and you need to plot a few lines or hatches in color. Ordinarily I'd advise you to convert the drawing from CTB (color table) to STB (style table), then set all the layers to plot with a black style except for the few that you want in color; those we would plot with the Normal style so that they plot with the layer color. However, whoever created this sheet didn't assign lineweights to their layers so many of the layer lineweights are still Default (i.e. not set) and hence the black line work wouldn't plot correctly.

Here's the tip:

The only colors that map to pens in a CTB drawing are the index colors 1-255. True colors, or Pantone colors, plot as displayed and do not map to CTB pens. So, use true colors for the layers or entities you wish to plot in color.

When you first click over to the True Color tab, you see all the true color information of the current standard index color. Click to select this same color as true color, then click OK.

Notice how the resultant true colors are displayed in the layer dialog. (I'll admit that I cobbled this together from some older existing drawing so ignore the poor layer names.)

Here's a portion of a plot using the TriSrv_F.ctb (Benham's old tried and true A/E/C CADD Standards pen table) and these few true color layers:
We still have the black line work that we normally expect in our plots, but we also have the added benefit of color for a presentation plot or a PDF plot.