Frequently Asked Questions

The list below should answer most of your questions. If you can't find an answer here, please send your question using the form on our contact page

What are your capabilities?

All bags are custom made to your client's specifications. Our capabilities are listed below. 

General capabilities.

  • Extruding film from 3" to 30" wide, 0.60 to 6.0 mil
  • Printing up to Six spot colors (6 colors on one side, 3 colors each side, etc)
  • Over two dozen film colors to choose from 
  • Fast turnaround - most orders ship within 2 to 3 weeks of art approval.
  • Low minimums - as low as 3000 bags. (Minimums are based on bag size and thickness, as well as number of print colors.  Smaller or thinner bags have higher minimums.  Bags with multi-color print will also carry higher minimums.)

What colors can be printed on on colored film?

We love seeing bold designs that make bags stand out, but it's important to follow some basic guidelines to get the best results.  

All colors will print well on white film. If your art has multiple, or bright, colors, white film is the best way to go.  Most inks print somewhat translucent or even transparent, which looks fine on white film, but on colored film, inks pick up the color of the film, or can disappear completely - especially on dark film. For instance, Blue ink on yellow film looks green, yellow ink on black film disappears completely, and red ink on beige or buff film will become burgundy.

On darker films, the best print colors are white and metallic colors (gold, silver, copper). White will print translucently on dark colors, picking up the film color slightly. On black film, white looks slightly gray, on navy blue film, white looks light blue, etc.

One way of visualizing this is to hold a piece of colored cellophane over something that matches the film color you want. 

Why does my quote list an over/under run amount?

While we try to keep overruns and underruns to a minimum, the production process has multiple steps, and the setup time and scrap produced for each step cannot be accurately predicted. This is due to the multiple steps process of extruding, printing, and converting bags, 

Steps to making bags

There are three basic steps to creating your bag, all of which require separate setup routines and create scrap material. All scrap is sent to a recycling center to be converted back into resin.  Here are the steps:

  1. Extruding the film – bags start as small pellets of resin, which are melted in an extruder and blown into a tube that matches the specifications for each order. The film passes through several rollers as it cools and is then flattened and wound on a large roll, ready to print. Scrap is created as the adjustments are made to create the correct film specifications.
  2. Printing – The roll of extruded film is then placed on a printing press. Press setup time and scrap created varies based on the number of colors being printed. Aligning printing plates to assure proper position can be very time consuming. 
  3. Converting – Once printed, the roll of film is moved to a converting machine that seals, cuts, and adds handles onto individual bags, which are then boxed up and prepared for shipping. 

How do I choose a bag size?

If unsure of the size of bag you need, feel free to contact us for help.

It is fairly simple to calculate the size of the bag needed, which starts with the measurements of what is going into the bag.

Here's some basics: 

  • The circumference of a bag without side gussets is  twice the width. A 12" wide bag has a 24" circumference. (12+12)
  • Circumference of a bag WITH side gussets is twice the width, plus twice the gusset. A 12" wide bag with 7" gussets has a 38" circumference. (12+12+7+7)
  • Bags can have gussets either in the side or bottom, but not both.
  • To get an idea of size, most grocery store t-shirt bags are about 12" wide, 22" high, with a 7" side gusset (called a 12x7x22). 

The circumference of the bag should be larger than the circumference of the items going in the bag.  This is generally only a concern when there is a specific size object needing to be bagged. 

If you have a box that is 9" long and 6" wide, its circumference would be 30". (9+9+6+6=30). Half of 30 is 15, so a 15" wide bag would fit perfectly, but it's best to get a slightly larger bag, around 16", to make bagging easier. You could also use a side gusseted bag, like a 10x6x22, which would have a 32" circumference. 

Bottom gussets in bags will help the bag sit flat when expanded, but do not increase the circumference of the bag. for that same 9x6 box, a 16" wide bag with a bottom gusset of 6" will hold the boxes nicely. 

How are bags measured?

Bags measurements are expressed as width x height (9x12, 15x18, etc) of the flattened bag. If bag has side gussets, the measurement is written as Width x Gusset x Height (12x7x22 is a standard T-shirt bag). If bag has a bottom gusset, the measurement is written as Width x Height + Gusset Width (15x18+4"BG for instance).

The height of the bag is measured from the bottom of bag to the top of the handle, except for Soft Loop Handle bags where the handle is attached and not included in the height measurement. You can see diagrams of bags as well as information about print area on our Print Area Information pages

About Printing Plates

Plastic bags are printed using flexographic plates that apply ink directly onto the bags.  Flexo plates can generally be used for many years without any degradation of image quality.


For printed bags, we highly recommend having your plates made through us. This streamlines the production process and creates far fewer headaches for you and your customers.

Some of our clients prefer to provide plates for their jobs, either because they have an existing relationship with a plate maker, or in an attempt to save money by ordering direct. Unfortunately, dealing with third party plate makers can create delays, and cost savings are usually minimal. Costs could even be higher in the long run if plates are made to incorrect specifications, contain errors, or become unusable due to cracking.

Advantages to having us make your plates :

  • TIME SAVINGS – No jobs can be added to our schedule until plates arrive. Our local plate maker delivers daily, and most orders arrive the next day. Customer provided plates can spend several days in shipping. If plates arrive damaged, or made to incorrect specifications, more delays can occur. 
  • PLATE PREPARATION – In production, plates are attached to printing cylinders with double sided sticky-back tape. The cost for the tape and labor for attaching the tape is included in our plate cost. On customer provided plates, there will be an additional charge for adding the tape to the plates. 
  • GUARANTEE – Plates made through us are guaranteed to match the art proof we provide. Customer provided plates are used as-is. We will compare to your art proof, but are not responsible for plate quality or for replacing plates if incorrect.
  • PLATE SPECIFICATIONS – If choosing to send us your own plates, they must match the specifications listed below. If plates are made differently, we may still be able to use them, but cannot guarantee they will work on our presses.
  • DAMAGE REPLACEMENT – Over time, plates wear out and crack, requiring replacement for future orders. Damaged plates made through us will be replaced without charge.  For customer provided plates, the customer bears costs for plate replacement.
  • QUALITY – For best results, art must be properly formatted before being submitted to the plate-maker. Our art department makes sure that all art files sent to the plate maker are correctly formatted. Incorrect art files can result in text shifts, fonts changing, incorrect line screens, and trapping issues.


Plates must be made to the following specifications:

  • Halftones printed at 35 LPI
  • 3M Cyrel .107 plate media
  • Backed with  3M 411DL sticky-back tape
  • Between .050 and .060 relief
  • 1" dead space around perimeter of image area
  • All crop marks (tick marks) must be removed
  • Etched center scribe lines
  • Beveled edges
  • Provide an art proof (PDF) showing proper art positioning on bag


Customer bears responsibility for making sure plates are made correctly. American Plastic assumes no responsibility for print quality due to plate abnormalities, damage, or errors. Additional charges will apply if plates require backing or other adjustments.

Digital proof showing art position on bag MUST be submitted either with plates or through email.


Improperly made plates can result in poor print quality or incur extra charges. Here's some common issues to be aware of.

  • Plates made from bitmapped images – may cause edge half-toning.
  • Plates made to incorrect specifications – may result in poor print quality, or may be unusable
  • Plates made with inadequate trapping – may result in poor image quality
  • Crop marks not trimmed off of plates –  marks will print on bag. Additional charges will apply to remove crop marks.
  • Double sided backing not attached – Backing has to be added. Additional charges will apply
  • Registration marks not included – Multiple color jobs may be registered incorrectly. Requires additional work and time to setup correctly. Additional setup charges will apply.

How do I prepare and submit Art?

All art should be submitted electronically, either through email, or by providing us a link to download the art. Contact us for information about where to send art. 


  • Vector Format Only - If art is not in vector format, we may be able to convert it. 
  • Preferred file format: PDF or EPS.  Files should be unlocked. Our artists need to be able to open and make adjustments to art files.  
  • Acceptable file formats: EPS, AI (CS5 or eariler), and CDR (X7 or earlier). If sending art in these formats, please provide a PDF proof. 
  • File formats that will incur art charges: TIFF, JPG, PSD, PNG, Word, PowerPoint, Publisher files must be converted to vector for printing.
  • Unacceptable file Formats: InDesign and QuarkXPress files cannot be used 
  • Printed Art received by mail or fax will need to be converted to digital vector files. Art charges will apply. 
  • All fonts must be converted to outlines (curves)  see “fonts and text” below..
  • Halftones and gradients are printed at 35-lpi, and should be limited to larger areas for best results.
  • Convert lines to objects - if objects have outlined edges, they should be converted into objects. The features of the outline - corners, dotted lines, thickness, etc - can shift. Thick outlines can also cause incorrect measurement of the art. Converting to a filled object will alleviate those issues. If you have questions, please Contact us 
  • TRAPPING - Film shifts up to 1/8" during printing and can cause registration issues. On multiple-color jobs, leave white space between colors if possible. If colors must overlap, trapping should extend by at least 4pt.  When setting trapping, be aware of the print order: lighter colors print first, followed by darker colors, and black will always print on top. If unsure of the order that colors will print on your job, please contact us.


What is Vector Art and why is it required?

Vector images are shapes and lines drawn in an illustration program (like Adobe Illustrator or CorelDraw) that have mathematical dimensions. This allows unlimited scalability without compromising the image quality. Images have smooth edges at all sizes, and file sizes much smaller than bitmap (raster) images. Common vector formats are PDF, Adobe Illustrator - AIEPS, and Corel Draw (CDR).  

While vector files are always saved in these formats, they can contain bitmap images as well. Saving a JPG image as AI or EPS or PDF does not change the image to vector. 

Bitmap images are made up of a series of individually defined pixels and have a fixed resolution. A 1” x 1” bitmap, at 300dpi, is 300 pixels wide and 300 high. Bitmap images CAN'T be made larger without losing quality. For printing, the higher the resolution of bitmap files, the better the image quality. Common bitmap formats are TIFF, JPG, GIF, PNG, BMP.

Why Vector? 

Vector art provides much smoother lines and edges to the art. Most bitmap images have smoothing (anti-aliasing) on the edges of the art (a slight gradient around curves to make them look smoother.)  All gradients are printed at 35 lpi, which when applied to shapes with smoothing, will result in slightly jagged edges.  

How do I specify ink colors?

We use coated (shiny) inks matched to standard Pantone PMS colors found in the Pantone Plus Formula Guide. When creating your art, we suggest referring to a PMS guide to specify colors.  

Art programs like Photoshop, Illustrator, Corel Draw, and others allow you to select colors from various pallets, and you should be able to select the Pantone Plus coated pallet to design your work. We will always provide a digital proof of your art in the colors specified, but keep in mind that colors may not look the same on screen, or printed on paper from desktop printers.

Computer monitors display in RGB color space (Red, Green, and Blue light) while most desktop and commercial printers use CMYK color space (Cyan, Magenta, Yellow, and Black ink). CMYK printing is used for Process Printing, where the four colors of ink are printed in screens (tiny dots) at different angles to create the illusion of all colors. RGB light from your monitor or TV is made up of tiny colored dots that your eye combines into other colors. 

We print using Spot Colors, which are just that - the color of ink specified. Because of the different color spaces, it is impossible to match a color with 100% accuracy across all devices. 

To find out more about color spaces and print processes, there are many articles available online that going into much more detail than we can provide here. 

Can Bitmaps be converted to vector art?

Yes, but not always easily. Depending on the complexity of the image, converting bitmaps to vector art can be simple or very time consuming. Many times, art can be electronically "traced" in a vector art program. Tracing doesn't always work very well with small text and small details can get lost. Converting more complex, or multiple color bitmaps to vector art sometimes requires rebuilding the art from scratch – matching fonts, and redrawing lines. Placing a bitmap into an illustration program and saving as an EPS or PDF does NOT convert the file to vector.

How do I Convert Fonts to Outlines? 

A font is a collection of letter defined as a specific typeface. The font file contains mathematical descriptions of the shape of each letter. Fonts can only be edited on computers where the font file is installed. PDF files can have embedded fonts, which will display and print properly, but cannot be edited by computers that don't have the font file installed. When opening the document on a machine that doesn’t have the proper font installed, programs usually substitute another font. Obviously, this can cause problems. Converting fonts to outlines disconnects the font descriptions from the letters, and prevents the shape from changing. The downside of this is that once the type is converted to outlines, it can no longer be edited as type.

To convert type to outlines, an illustration program like Adobe Illustrator or CorelDraw is required. Adobe InDesign is also capable of converting type to outlines. In Illustrator or InDesign, chose “create outlines” from the Type menu. In CorelDraw, select “Convert to Curves” from the Arrange menu. 

What is the difference between DPI, PPI, and LPI?

Both digital bitmap images and printed images are made up of a series of dots. The terms DPI and PPI are usually confused these days. 

  • DPI – Dots Per Inch –the resolution of a printed image, how many tiny dots of ink printed per inch. The more dots, the finer the print. 
  • PPI – Pixels Per Inch – Most times when people refer to DPI, they really mean PPI.  Simply the number of pixels per inch (vertically and horizontally) in a digital image
  • LPI – Lines Per Inch – refers to the lines of in a halftone or screen - the higher the number, the smaller the screen. These dots are not the same as those defined by in DPI. 

DPI and PPI when referring to a digital image are fairly meaningless without knowing how many inches an image is. The image resolution is determined by the number of pixels in an image. An image that is 10" wide at 300dpi is 3000 pixels wide, could also be defined as 100" at 30dpi, or 1" at 3000dpi. 

In printing, DPI is the number of dots of ink per inch, and is generally a higher number than the image PPI, and the PPI is a higher number than the LPI.

For most commercial printing applications, digital images need to be a minimum of 300 PPI at full size. If there are image areas that will be printed as halftones (not a solid color), the LPI indicates the number of lines of dots per inch. For many print applications, LPI is approximately half the number of the PPI. For the process that we use for plastic bags 35 is the maximum LPI that prints well. This produces fairly large dots compared to offset printing. As an example, most newspapers print images at around 80 LPI, and most magazines at around 150 lpi or higher.  

Below is an image of 50% gray converted to 35, 80, and 150 LPI, click for full size.

American Plastic Mfg., Inc. |  526 South Monroe St, Seattle, WA 98108

(888) 763-1055  |  (206) 763-1055  |  FAX (206) 763-3946

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