Some printers, such as the Hewlett-Packard HP4si, have multiple paper
trays. You can set up Dvips to take advantage of this using the
bop-hook PostScript variable (see section PostScript hooks).
For example, suppose you have an alternate tray stocked with letterhead
paper; the usual tray has the usual paper. You have a document where
you want the first page printed on letterhead, and the remaining pages
on the usual paper. You can create a header file, say
`firstletterhead.PS', with the following (PostScript) code
(bop-hook is passed the current physical page number, which
starts at zero):
/bop-hook { dup 0 eq { alternatetray } { normaltray } ifelse } def
where alternatetray and normaltray are the appropriate commands to select the paper trays. On the 4SI, alternatetray is `statusdict begin 1 setpapertray end' and normaltray is `statusdict begin 0 setpapertray end'.
Then, include the file with either