Frequently Asked Questions about Producing for OOH

Should I build my artwork to the actual size of a billboard?
What size do I build my files to?

Please do not build your files to actual size! Because outdoor advertising is larger-than life, it’s unrealistic to create digital artwork to the product’s actual size (files would be enormous and take forever to process!!). Instead, build your files to an intermediate size (a reduced size) which is much more manageable through the production process. Your files will be enlarged digitally to the final dimensions as part of the production process.
Each OOH product has it’s own set of specifications and unique requirements. Similarly, each printer will have unique requirements for production depending on their production method and existing technology. Always check with your printer for their production and file requirements.

What is the difference between screen printing, lithography and digital printing?

Screen printing, Lithography & Digital printing are the 3 main production methods employed for OOH print production.

Screen printing or lithography are ideal production methods for large-volume paper products. Both methods produce images on paper with layers of ink organized in a dot pattern, called LPI (see below). Both methods are faster than digital printing when it comes to printing large quantities, their main differences exist in quality and price. Screen printing produces a coarser line screen and can take longer to print and dry than lithography, but can be more cost-effective for medium-sized runs. Lithography is printed at a finer resolution and is faster and more cost-effective for medium to large production runs.

Screen-printing is cost efficient for low to mid size quantity production runs and for printing on plastics and usually outputs a coarser looking image. A very simplistic description of the process involves the creative image being burned onto a screen with a hardened emulsion. Ink is then squeegied through the screen and onto the substrate.

Lithography is cost efficient for mid to large size runs and produces a finer image. The process involves burning images onto metal plates and mounting the plates to a printing press. Ink is applied to the image areas on the plates, then transferred to paper as it moves through the press.

Vinyl products or low-volume paper products are normally produced using digital print technology, usually roll-fed ink-jet or flat-bed digital presses. Creative files are processed on a desktop computer and the image information is transferred to the digital press. Printing heads move across the length of the press and map out the image in ink on the substrate. Digital print resolution can be very fine, creating photo-quality images, but is much slower than screen print or lithography. Digital printing is cost effective for very low to mid quantity runs and can produce coarse to fine images depending on the type of equipment that is used. The higher the resolution, the more costly the print is.

What is LPI?

LPI (Lines Per Inch) is a standard print industry term used to measure the resolution of a printed image, by how many lines of dots appear per inch. LPI is used only in print methods that use organized dot patterns to create images, such as screen printing and lithography. The higher the LPI number, the more dots there are per inch and the dots are smaller, which results in a finer resolution and smoother image.

Newspapers are typically printed in a resolution of 85 lpi, while magazines may use 133 lpi or higher. Because Outdoor advertising is always viewed at a distance, it is perfectly acceptable to print posters and transit shelters at a low LPI.  For example, transit shelters normally print at 75-100 LPI, and posters can print as low as 15 LPI and still look great on the street!

What is CMYK? How is it different from RGB?

CMYK stands for Cyan, Magenta, Yellow, and blacK. Almost all digital, screen print and lithographic production is printed using inks in these four colours. Combining different sized dots of these four inks can make millions of colours. That way, you don’t need to use a different ink for every colour that appears in your ad. 

However, cameras and monitors display colours in combinations of Red, Green and Blue (RGB). These colours don’t always translate well when printed, so it’s important to supply artwork to your printer converted to CMYK.

What is “paper stretch”?

Outdoor paper posters that are printed in sections are subject to “paper stretch”. Once the paper is printed, it is soaked in a wet glue solution for up to 3 days prior to being posted. The longer the paper sits in glue, the more moisture it absorbs and the fibres in the paper become elongated, or stretched – sometimes the paper can stretch up to six inches. The amount of paper stretch can vary depending on weather conditions and how long the paper has been sitting in glue.  Paper stretch should always be taken into consideration by the printer. And because the exact amount of paper stretch cannot be predetermined, it is important that all critical design elements are kept within the defined safety areas and that borders are not used as part of the creative.

How does paper stretch affect borders?

Posters are traditionally posted from the left side to the right. As the billposter moves across the board, each sheet will stretch slightly so that by the time you reach the right edge, the creative may have stretched up to six inches in total. This excess paper gets trimmed off the right side of the structure so that it doesn’t hang off the board. If a creative has a border on it, some of the right side will most likely be trimmed off and the creative may look lop-sided.

How do I know how many posters to print?

Your Outdoor Media company will advise you how many posters to print based on the length of your contract. They have standardized overage formulas for each product based on years of experience and can recommend how much overage is needed for your campaign.  If you are planning multiple designs, or have specific posting instructions, notify your Outdoor company as soon as possible as the number of designs or special instructions may impact the quantity of paper and the shipping instructions.

Why do I have to print more posters than the number of locations I bought?

There is always a “renewal” factor calculated in the number of posters needed for an Outdoor media campaign. This renewal paper covers any damage that may occur due to weather or vandalism. Transit Shelter paper can be reused, though extras are still required because of wear and tear. Posters may also be moved from location to location. However, paper posters that are glued to structures need a brand new poster every time the location is changed.

Renewal quantities (sometimes called “Overs”) are calculated based on the media product, length of the campaign and rotational requirements. The formulas used to calculate paper quantities are based on years of experience dealing with the wear and tear of Mother Nature and any vandalism or theft that may occur. Providing the requested paper quantities ensures there is enough material to complete the entire media showing without interruption.  It is always less expensive to have excess material printed with the initial production run rather than later, particularly for large campaigns.

Are there any colours I should avoid when planning my creative? Why??

For most outdoor products, you can use as whatever colours you like – there are no limitations.  However, for horizontal or vertical paper posters, solid black or dark backgrounds are not recommended. When posting glue dries on the paper, it can leave visible white brush marks. If there is alot of detail in the creative, these brush marks are not visible, but if the creative has a solid dark background, they can be very visible and can make dark backgrounds look dirty.

What is the difference between Trim, Visible Opening and Safety?

• The Trim Size is the finished trimmed size of the poster, ready for posting
• The Visible Opening is the area of the poster that is visible inside of the structure’s frame. Not all products have frames, therefore, not all products will have separate Trim and Visible Opening dimensions.
• The Safety is the area that all type and critical elements should be kept within to ensure that they are seen and won’t be cut off due to paper stretch or minor differences in hanging the ad. This is sometimes also called “Live Area”.

What is a “rainlap”?

“Rainlaps” are used on paper posters that are printed in multiple sections. This is an unprinted edge on the right and top edge of each sheet that allows the overlapping sheet to stick better.  Rainlaps are configured a certain way to ensure that when it rains, water does not puddle on the sheet edge and cause the poster
to flag.

Does each Outdoor company have to print their own posters?

For most standard products, you can have production done at any printer with large-format capabilities. However, always check with your Outdoor media company first, as some products are proprietary and must be produced at a specific location for operational reasons.  Regardless of who is handling your production, always check with your Outdoor company for their production requirements. All material supplied to the Outdoor company should adhere to the company’s specifications to minimize delays and extra charges.

Where do I ship my posters to?

Each Outdoor company will supply shipping instructions to the client or agency that signed the media contract. If there are multiple designs, or specific posting instructions, the Outdoor company should be notified immediately as it may impact the quantity of paper needed and shipping instructions.

What are the optimum leadtimes for production?

Because of it’s size, outdoor advertising takes much longer to produce and distribute than commercial advertising. Most outdoor products can be printed and shipped within two weeks of receipt of creative files. Depending on the product, and the volume of your production run, files/artwork should be ready for production a minimum of two weeks prior to your posting date to allow for file preparation, proofing, printing, finishing, and delivery. It is always best to check with your printer for their art delivery deadlines.  Some Outdoor companies like to have their paper in the markets three to five working days prior to the posting date, so it is a good idea to have creative files prepared and ready for printing three weeks prior to the first posting date.

Will the Outdoor companies store my printed materials after my campaign is over?

No, there are time limits to how long each Outdoor company will inventory advertising material once a campaign has finished.  Check with your Outdoor company for their policy on storing old materials.