Graphics Programs Reference
In-Depth Information
Fig. 6-15
Photoshop's
Image Size dialog shown
here with the native
output resolution for my
Pictrography 4500 set at
266 ppi using the Nearest
Neighbor algorithm.
the target is 12 inches and ignore the 72 dpi resolution tag. The result is
the Epson will produce a print that is 12 inches in size. The patches will
output to the correct size. If you are sending targets to an outside lab for
printing, and your Spectrophotometer expects a specific patch size, be
sure to discuss with the shop how their printer will behave. You may
need to size the target as I did with Pictrography. If the output device
behaves like the Epson, just send the target but inform the shop that the
output size must be 100 percent. Some targets specify the necessary
output size on the target (see Fig. 6-14). This allows a user to measure
the output and ensure that the printed piece is the correct size.
A few printers are not consistent in producing color or tone across the
entire page. That is, ink density might be heavier or lighter on one side
of the page versus the other. This usually is seen with larger format print-
ers or some printing presses. If you suspect this is the case and account-
ing for this is important, place multiple targets on the page so that they
can be measured and eventually averaged (see the sidebar, “Averaging
Measured Data”). In some cases, it is a good idea to gang up several of
the same targets across the entire page of a printer. Rotate the target right
side up, upside down, and so forth. This ensures the patches are spread
around the page in such a manner that the resulting measured data
accounts for variation across the page. If you ever have the opportunity
to profile a printing press, it is often useful to select and measure a target
printed from the beginning, middle, and end of the press run. This can
average the variations of the entire print run. Although this involves
more work in measuring more targets, the resulting profile will produce
a far better assessment of the condition of the output device.
The targets to be printed usually are untagged RGB or CMYK docu-
ments. An embedded profile isn't necessary since all we need to do is
send these specific, known color values to the output device. It is vital
that targets undergo no data conversion into a working space or any other
