Fill Between Curves Prints Faintly

Carol Tremblay · Post by **Carol Tremblay** » Tue Oct 04, 2011 12:25 pm

I used the fill between curves option which looks fine on the screen. When I print the figure, you can barely see the fill. This is true regardless of the type of shading I choose. Help!

Post by **DPlotAdmin** » Tue Oct 04, 2011 8:05 pm

I'll have to play around with this on a color printer, but it is most likely a resolution-dependent problem. The fill patterns other than solid use lines that are 1-pixel or 1 printer dot. With light colors or depending on how your printer simulates colors, these may be either barely visible or sure-enough invisible.

Thanks for pointing out the problem. I'll definitely take a look and most likely come up with my own fill patterns that are resolution-dependent.

Post by **DPlotAdmin** » Wed Oct 05, 2011 12:34 pm

... on the other hand, I've tried a couple of examples and they print out very nicely - the patterns are very visible using red, green, or blue.

Perhaps there is something about your graph(s) that I've not considered. At your convenience please save a graph you're having trouble with as a DPlot file and send it to me, along with letting me know what printer you're using.

Post by **DPlotAdmin** » Wed Oct 05, 2011 1:51 pm

Thanks for the file. It has been too long since I've used a B&W printer, but my guess is the resolution is high enough that the 1-pixel wide lines used in the fill patterns are just too thin to be useful. Does the appearance improve if you use pure black? If so, then there is an additional problem of the printer's dithering ending up producing mostly white dots even though your fill color is very close to black.

At the moment (if switching to black doesn't help) my only suggestion is to print at a lower resolution. This of course is not my idea of a good solution. I need to come up with resolution-dependent fill patterns so that (for example) a pattern using 1-pixel wide lines on the display will use ~12-pixel wide lines when printed at 1200 dpi.

Carol Tremblay · Post by **Carol Tremblay** » Wed Oct 05, 2011 2:11 pm

The fill I used was black. Printing at lower resolution helped.

Post by **DPlotAdmin** » Wed Oct 05, 2011 2:17 pm

In the example you sent the fill color is 51,51,51: a dark grey.

Carol Tremblay · Post by **Carol Tremblay** » Wed Oct 05, 2011 2:28 pm

Well, now that I see how to read the color chart

, the black did the trick! Thanks.

Post by **DPlotAdmin** » Wed Oct 05, 2011 3:19 pm

You're welcome, but I probably still need to do what I said about adding fill patterns with wider lines.

Just an FYI: most B&W printers simulate colors other than black and white with dithered patterns. For a 1-dot wide line, that pattern may work out well or it may result in nothing at all - no lines.