why the '.pdf' figure produced by gnuplot is large than matlab?

I used gnuplot to plot a stacked bar figure, the produced .pdf file is 50k. But the figure produced by matlab is 1-9k usually.

When I inserted the gnuplot-produced pdf figure in latex (pdflatex), and open the paper, the figure seems need re-produced (the stacked columns show one by one).

here is the command

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set style histogram rowstacked#errorbars gap 1 lw 3#c开发者_如何学Pythonlustered

set style data histograms

set bar

set term postscript eps color "Helvetica" 24

set output "file.eps"

plot

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the size of the output 'file.eps' is 26k. the size of 'file.pdf' produced by epstopdf is 65k.

Thank you.