- What is dpi? What is lpi? What should I scan/set my files at?
Dpi stands for dots per inch, and when displayed on screen this is also
often referred to as ppi (pixels per inch). On screen, what would be printed as dots is displayed
using pixels because there are no "dots" on monitors. When printing however, images are printed using
dots (if you look closely at virtually any printed piece you can see them). Dpi measures
the overall resolution of an image in reference to these dots.
Lpi stands for lines per inch, which
corresponds to the number of lines per inch in a halftone screen. This concept is slightly more subtle
than the concept of dpi, because it also involves dots, but dots that are often referred to as "machine" dots
(and there happens to be a nice correlation between lpi and dpi to guide what to set your files
at). To understand lpi, it is necessary to see that a printing press can only print solid color, so
to get percentages of color, the solid color is screened, or rather, very small solid dots are
put on the paper to simulate tones. Lpi measures how many lines, that make up these screens,
are in one inch, and is a measure of resolution with respect to offset printing.
The primary thing to
remember is that dpi is something that you should set when creating your files in a non-vector format
but lpi, except in very rare cases, should not be set or locked into your files, it will be automatically
set by our RIPs (the thing that interprets your file and allows us to proof and plate it).
between dpi and lpi that was mentioned earlier, is that the rule of thumb is to make images approximately twice
that of the linescreen. Brenner Printing prints all sheetfed books at approximately 175 lpi and newsprint
books at 150 lpi, meaning that images should be created at 350 and 300 dpi respectively. However, this is
just a rule of thumb, and most people will find that 300 dpi shows no degradation from 350 dpi and saves them
One other exception to especially note is: although type should not be embedded inside non-vector graphics
when this is unavoidable, the dpi should be set at or above 600 dpi.
And finally, lineart should be set at 1200
So once again:
- Don't set or lock in lpi (rare exceptions: if you don't already
know the exceptions, you should abide by this rule)
- 300-350 dpi for grayscale and process pictures (at size)
- 600+ dpi if placing type in bitmap graphics
- 1200 dpi for lineart
- How can I get my files to you?
There are three main methods:
- Media (Zip, CD, DVD, etc) - Please see Digital Prepress page
- FTP - For information, please see FTP under hints
- Email - For information, please see Email under hints
Incidentally, the first tends to be the fastest given the size of the files
that make up entire projects, and continues to be the recommended method.
- What kind of files/programs do you accept/recommend?
As far as accepting, check the Digital Prepress page. We recommend Adobe
products (PageMaker, Illustrator, PhotoShop, InDesign), but acceptable substitutes for these recommendations
would be QuarkXPress for PageMaker or InDesign and Freehand for Illustrator. PhotoShop literally has no substitute,
it is the de facto standard for image manipulation. If you are planning on using these programs, it would be
advisable to read the manual (compared to most programs, these manuals are invaluable and actually readable). All
of the above are very powerful programs, and understanding their features will make the whole process
- Will you accept a RGB File?
We prefer that files sent to us are CMYK. As there can be significant color
shifting while converting an RGB to CMYK, we feel it best if the client make that conversion.
- How can I check my job before it is printed to make sure everything is alright?
You can get a proof, in fact, we encourage it. See the Digital Prepress page for details
on our proofing process.
- Are you a CtP (Computer-to-Plate) shop?
Most definitely. While we still maintain the capability to make plates from film, we no
longer make film. Going to CtP increases our productivity, lowers total cost, and allows us to produce
perfectly registered crisp printing.
- Any more tips?
Check out the hints section.
- I have more/specific questions.!?
Call us. A representative from the digital prepress department will be happy to speak to
you about your project.