When you start designing artwork for large
format output, it's helpful if you know some
of the limitations that you're going to face
in the graphics programs that you frequently use.
For example, there's a limit to how big you can build a file.
InDesign will let you build a page that's
18 feet by 18 feet, which is pretty generous.
And, it will let you combine ten of those pages in one spread.
So, that would be 18 feet by 180 feet.
Now, that sounds like more than you'd ever need,
but, for example, if you look at a 20
foot by 60 foot billboard, clearly, you can't build
it tall enough because you're limited to 18 feet.
So, you find that you build at a reduced size, and
we're going to talk a little bit more about that in a minute.
Illustrator has its limitations.
The maximum canvas size is 227 and a half inches on a side.
Now, within that canvas you can have multiple artboards.
If you build one artboard right to the edge though that's as big as you can go.
And Photoshop doesn't handle it in terms of dimensions, it thinks in pixels.
So, your resolution would determine the dimensions, but
you're limited to 300,000 pixels on the side.
That's a lot, but it's not big enough to build some things at full size.
Besides, you'd build something that's really
enormous and would take forever to output.
So, if you build at a smaller size, what's the maximum output scale factor?
In other words, if you make something and you want to
output it at twice size or four times the size.
What are your limits?
InDesign's limit is 1000%, that's ten times the original size.
And Illustrator has the same limitations.
Again, Photoshop isn't thinking in terms of percentage output, it's
thinking in terms of maximum 300,000 pixels in terms of output.
So, what that means is that if you built an image that was 300
pixels on the side, the maximum output size would be ten times that, 1000%.
Of course, what you need to do is follow the printer's specifications.
So, some of the frequent suggestions are build all-vector if possible.
And then, the size that you're working at isn't really
so important because that output can be scaled up, scaled down.
It's not going to lose any detail because there aren't
any pixels, and that's the beauty of vector art.
Now for billboards, some printers will ask you to build at a one to ten scale.
It varies from vendor to vendor and it
also varies depending on the size of the billboard.
There is not just one size of billboard.
For things like posters and in-store banners, usually
you'll be asked to build at half final size.
But as part of that, you also have to
take into consideration how you're going to handle image resolution.
So, what happens when you start designing at reduced size?
Well, one of the things you're trying to do is speed your design
work because you don't want to be
hoisting around enormous Photoshop images, for example,
and also that output consideration, that
processing, the ripping that takes place, the
more it has to chew on the longer its going to take to process.
So, why would you design at a reduced size?
Well, as I mentioned earlier, there are some limits to the application sizes.
And if you are using InDesign to build a 20 foot
by 60 foot billboard, clearly you can't build it to full size.
And then, the other consideration is to manage the file size
during the design and to manage the file size during output.
Because after all, more data means more processing, both while
you're designing, looking at your screen and moving things around.
And when that job gets sent to the imaging device,
you want enough, but there's no point in having too much.
So, here's how you have to think about image resolution if
you're building at a different size from the final output size.
Don't be intimidated by the brackets and parenthesis.
The final resolution that the printer asks you to
provide times the output factor is the working resolution.
So, let me clarify that.
For example, the printer has said okay, the final output size
I need for your image is to be 150 pixels per inch.
And you're building it half size.
So, 150 pixels per inch, at the final size, times the 200% scale factor.
In other words, you've built half size.
When he goes to print he's going to print at 200%.
And that gets him up to the final size.
So your, 150 pixel per inch images that he wants.
That's going to require that you build with
300 pixel per inch images placed at 100%.
So, if you have a 300 pixel per inch image, you're working in your half
size design and you place that image at
an increased size, you've already lost some resolution.
So, always place at 100%.
And then, when that 300 pixel per inch image that you're working in in
your half size design is output at the printer at that twice scale factor.
Then the final image res is going to be 150 pixels per inch, I know it's
a lot of numbers, let's go through another one and maybe it'll kind of make sense.
Let's say the printer wants 300 pixels per inch at final size.
You're building it half size.
It's that same resolution recipe.
300 pixels per inch, the final size, times the scale factor when he goes to output
it, 200%, equals the resolution that you need
to be working at in your half-size design.
So, in this case, you would put 600 pixel per inch images.
I know that seems like a lot, but remember, you're working in a half size.
But, again, you gotta place them at the correct size.
Place them at a 100%.
And then, when that 600 pixel per inch image is output at 200%,
the final output resolution it's going to be 300 and that's what he's asked for.
So, I know it's a lot of numbers, but hopefully it starts to make sense now.
So, what's the final size?
Well, there isn't just one final size.
Outdoor signs come in a variety of dimensions.
So, you really need to know, at the
beginning of your job, what you're designing for.
And, with large format output, as with any kind
of printing, always consult with your printer and do
it early in the game, so that you can
prevent problems later on, when that enormous billboard is printed.