GGSAVE does not save a good version of my graph

I am running R in RStudio. I am creating a graph, which I see in the plot w=
indow, and I use ggsave() to save a copy of the graph in a file. =


When I use look at the graph is RStudio's Plots window, the graph looks fin=
e. When I click on the Plot window's export button, copy the plot to the cl=
ipboard and paste the graph into MS word, the graph looks fine. Please see =
first figure on attached MS word document.

When I copy and paste the .tiff file saved by ggsave, the graph looks bad. =
Second figure on the attached MS word document. I think the graphs is being=
 exported improperly by ggsave. I would appreciate any suggestions for impr=
oving the quality of the graph produced by ggsave. =


Please see code below and attached MS word document




# Code to produce graph
 ## Plot
  zz <- ggplot(
    df.long,
    aes(
      x =3D Date,
      y =3D NumPeopleExposed,
      color =3D factor(criticalvalue),
      linetype =3D factor(criticalvalue),
      group =3D factor(criticalvalue)
    )
  ) +
    geom_point(size =3D 3) +
    geom_line(linewidth =3D 1.5) +
    =

    scale_linetype_manual(
      values =3D c(
        "solid",
        "dashed",
        "dotted",
        "dotdash",
        "longdash",
        "twodash"
      )
    ) +
    =

    labs(
      title =3D species,
      x =3D "Date",
      y =3D "Number of People Exposed to Toxic Concentration",
      color =3D "Critical Value",
      linetype =3D "Critical Value"
    ) +
    =

    ## Show every date on x-axis
    scale_x_date(
      breaks =3D sort(unique(df.long$Date)),
      date_labels =3D "%Y-%m-%d"
    ) +
    =

    theme_bw() +
    =

    theme(
      axis.text.x =3D element_text(
        angle =3D 45,
        hjust =3D 1,
        vjust =3D 1
      )
    )
    print(zz)

Code to save the graph
 current_time <- Sys.time()
  current_time
  # Convert colons to dashes, remove spaces
  formatted_time <- gsub(":", "-", format(current_time, "%Y-%m-%d_%H-%M-%S"=
))
  formatted_time
  =

  #species=3D"JDS"
  # Save graph
  mypath <- file.path("C:","Users","JSorkin","OneDrive - University of Mary=
land School of Medicine","HalemMilton","PaperAndAbstract")
  mypath
  =

  myfilename <- paste0(species2,formatted_time,".tiff")
  myfilename
  =

  ggsave(plot=3Dzz,
         path=3Dmypath,
         filename=3Dmyfilename,
         device=3D"tiff",
         width=3D4,height=3D3,
         units=3D"in",
         dpi=3D600)

  cat("Ending (12) Plot Fraction Exposed\n")
  }




John David Sorkin M.D., Ph.D.
Professor of Medicine, University of Maryland School of Medicine;
Associate Director for Biostatistics and Informatics, Baltimore VA Medical =
Center Geriatrics Research, Education, and Clinical Center;=A0
Former PI Biostatistics and Informatics Core,=A0University of Maryland Scho=
ol of Medicine Claude D. Pepper Older Americans Independence Center;
Senior Statistician University of Maryland Center for Vascular Research;

Division of Gerontology, Geriatrics and Palliative Medicine,
10 North Greene Street
GRECC (BT/18/GR)
Baltimore, MD 21201-1524
Cell phone 443-418-5382