Paper – Frequently Asked Questions
Questions About Paper Coatings
An aqueous coating is a water-based coating with a matte or gloss finish which improves durability and protection.
Aqueous coatings offer good resistance to abrasive scuffing or rubbing and protects the surface from scratches, fingerprints, dirt, and smudging.
Coating finishes are applied after the ink. Coatings are used to enhance the appearance of graphics. They also protect the printed surface from scratching, marring, fingerprints and dirt by increasing rub and scuff resistance.
Coating finishes improve durability of the printed pieces during shipment through to the end use of items such as postcards, brochures, catalog covers, flyers, and product labels. Coating finishes can also be used to enhance economy-grade paper by improving gloss and providing a smoother touch.
Cross section of uncoated paper printed with coating added
Cross section of coated paper printed with coating added
Once the sheet is manufactured, an uncoated paper surface can be coated with white clay materials. The clay gives the paper a smooth feel by filling microscopic valleys on the paper surface.
The coating also limits the absorption of inks into the paper. Because the inks stay on the surface of the coating instead of soaking in, the ink appears richer, sharper and glossier. Text, images and photos stand out more than on uncoated. However, writing and ballpoint pen inks take longer to dry on coated paper and smudge easily. Less ink is needed on coated papers.
Coatings are offered in a range of reflectivity values including dull, matte, silk, satin or glossy. Reading text is easier when printed on dull or matt finishes. After printing images on dull or mat stock, a varnish can be applied to the picture areas to add gloss and make the pictures pop.
Coated paper cross section illustration
In overall UV coating, a matte, silk, satin, or glossy finish is applied to the entire printed sheet. The coating is applied and then exposed to an ultraviolet light which rapidly cures it and bonds it to the paper.
A matte, silk, satin or glossy finish can be applied to specific spots of the printed piece such as photographs or other graphic images.
Spot UV coating, like overall UV coating, is also rapidly dried and cured via ultraviolet light.
Print files must be prepared in advance to show the areas that will receive the coating.
For example, in the illustration below, the black indicates where a spot UV coating is to be applied on a printed sheet.
“Uncoated finishing” is simply another way to say that a protective coating or varnish will not be applied to the printed piece.
The printed piece will consist only of paper and ink. The illustrations below show uncoated and coated papers without any coatings.
All paper stocks begin life without a coating. Uncoated paper is porous with an uneven, rough surface. As a result, uncoated paper is easier to write on as it absorbs ink readily and dries to the touch faster. However, the heavier ink absorption results in less rub resistance.
Uncoated stocks include bonds, offsets, card, and newsprint.
The illustration below is an illustration of the paper’s cross section.
Aqueous coatings are dried by hot air. UV coatings are dried and cured by ultraviolet light. UV coatings are tougher and more slippery than aqueous.
You can write on aqueous coating, but not on most UV coatings. UV coatings can achieve a higher gloss than aqueous.
Because of the differences in these coatings, it’s important for designers and manufacturers to communicate with their print vendors from the beginning of every project.
Aqueous coatings are less costly than varnish. Aqueous coatings dry in minutes while conventional varnishes need a few hours or days to dry.
Aqueous coatings don’t yellow with age while varnishes tend to take on a yellow tint.
Coated paper is produced at the paper mill with a smooth surface. Coated stocks have a range of reflectivity values including dull, matte, silk, satin or glossy.
A coating finish on the other hand is produced at the printing company. It’s a clear layer applied after the ink is printed. It enhances the visual appeal of printed graphics. Coatings also add various levels of durability, shine, and protection to the printed surface.
Paper with a gloss finish is shiny (it reflects a lot of light) while matte paper is flat and dull in appearance with little shine or light reflection.
Gloss stock makes colors look smoother, deeper, richer, with great color-contrast. Photos and graphics tend to look better on gloss stock, while text heavy documents and artwork generally are more visually appealing on matte papers.
Text is also easier to read on a matte finish. The softer dull surface of matte paper offers good color contrast and clarity.
Paper with a coating is smooth and shiny while uncoated paper has a rougher texture and flat finish with little or no shine. Gloss stock makes colors look smoother, deeper, richer, with better color-contrast than uncoated stock.
Photos and graphics also tend to look better on gloss stock, while text heavy documents and artwork are typically more suitable for matte stock.
Text is easier to read on paper with a matte finish. The softer looking dull surface of matte paper provides color contrast and clarity. Unlike glossy paper, matte stock is more forgiving of fingerprints, dust, and smudging.
Uncoated paper is very absorbent, and ink dots will tend to spread outwards (i.e., dot gain).
This leads to a darker image that doesn’t reproduce as precisely as it does on coated paper.
It’s similar to what happens when a paper towel is placed on a drop of liquid. The droplet increases in diameter and the edges become ragged.
Dot gain can be minimized using sophisticated printing techniques, but it can’t be eliminated. Coated paper is less absorbent and therefore dot gain is less of an issue.
Questions About Paper Sizes and Classifications
“Sometimes I see “10 pt” or “12 pt” paper stock listed. Is this a paper weight?”
Sometimes the thickness of Cover stock (also called Card stock) is used instead of its weight. It’s also often used in addition to its weight.
In North America, paper thickness can be displayed in points. 1 point (1 pt.) is one thousandth of an inch (1/1000″ or .001″). For example, a 10 pt. Card stock is 0.010″ thick (about the weight of a 140lb Index stock) while 12 pt. Card stock is 0.012″ thick (about the weight of a 100lb Cover stock).
Thickness is a critical factor in printing for various reasons. Postcards and self-mailers, for example, require minimum thickness paper to quality for USPS mailing.
Paper thickness also determines whether a job can be folded by machine or needs to be folded manually.
Paper board thickness is a factor in product packaging and folding cartons (unit cartons.)
When in doubt, contact us to discuss the appropriate paper thickness for your job.
What’s the difference between paper being labelled with lb, #, gsm, g/m2, and g/m2?
Besides a generic “Text” weight or “Cover” weight, paper descriptions use a number to refer to the weight of the paper. The higher the number, the heavier the paper. Heavier paper is typically thicker as well.
There are two systems for indicating the weight of paper; an international metric system (ISO) and the North American ANSI and ARCH system. The North American system for paper weight uses pounds (expressed as either # or lb).
The North American pound rating, also called a basis weight, is based on the weight of 500 sheets (a.k.a. a ream) of a specific size.
There are 5 basis weight categories:
- Text (Basis size = 25 x 38”)
- Index (Basis size = 25.5 x 30.5”)
- Bristol (Basis size = 22.5 x 28.5”)
- Cover (Basis size = 20 x 26”)
- Bond (Basis size = 17 x 22”)
The U.S. system is a bit confusing because the same pound number (weight) can be used for both lighter (Text) paper and heavier (Cover) paper. For example, 80# Text paper and 80# Cover paper have the same pound number even though the Cover stock is almost twice as heavy!
The reason for this is the text stock “basis” uses 500 sheets measuring 25″ x 38. The cover stock “basis” uses 500 sheets measuring 20″ x 26″.
The metric ISO system in comparison is more straight forward because it uses one “basis” unit of reference. The metric system uses grams per square meter (gsm or g/m2 or g/m2), often called “grammage”. The ISO rating is based on the weight of a single sheet of paper that measures 1×1 meter. Simple.
For example, 80# Text Paper weighs 104 g/m2 while 80# Cover Stock weighs 218 g/m2. The Cover stock is clearly more than twice as heavy as the Text stock.
Paper is typically grouped into two main grades based on weight and thickness: Text and Cover.
Description of Text Papers
“Text” is a generic name for a variety of light, thin paper stocks that includes Book, Bond, Writing, Ledger, Offset paper.
Text paper is flexible, is easily rolled and folded, and is used for flyers, handouts, letterheads, and books. For example, the paper used in ink jet printers is considered Text.
Description of Cover Papers
“Cover” is a generic name for a variety of heavier and thicker paper stocks that includes Bristol, Index, Tag, and Card paper.
It is more substantial and durable than Text paper. Cover paper is more rigid and must be scored (creased) before it can be folded.
Cover papers are typically smooth but there are textured variations. It can have either a matte or glossy appearance.
Cover or Card stock is often used for mass mailed postcards, business cards, playing cards, invitations, program covers, greeting cards, door hangers, catalogue covers, presentation covers, scrapbooking, folding cartons, packaging, retail displays, and more.
The ISO B series of paper sizes is slightly larger than the A series.
Over time it became necessary to classify larger sheets of paper that were coming in to use in printing.
You can see a listing of ISO A and B series in the size chart below.
ISO 216 (International Organization for Standardization) is the international standard for paper sizes.
It’s used around the globe except in North America and parts of Latin America. This paper standard, like ANSI and ARCH paper standards, are used to classify paper for various uses in printing and graphic reproduction.
All ISO 216 papers have an aspect ratio based on the square root of 2, which is 1.4142. The primary basis size, A0, has a 1 square meter of area (and of course, the aspect ratio 1.4142.)
The B series of paper sizes was created to provide a series of larger paper sizes than that of the A series.
The ISO paper charts below show how each size in the series relates to the other.
ISO A Sizes of Paper
A0
841 mm x 1,189 mm
(33.11 in. x 46.81 in.)
A1
594 mm x 841 mm
(23.39 in. x 33.11 in.)
A2
420 mm x 594 mm
(16.54 in. x 23.39 in.)
A3
297 mm x 420 mm
(11.69 in. x 16.54 in.)
A4
210 mm x 297 mm
(8.27 in. x 11.69 in.)
A5
148 mm x 210 mm
(5.83 in. x 8.27 in.)
A6
105 mm x 148 mm
(4.13 in. x 5.83 in.)
A7
74 mm x 105 mm
(2.91 in. x 4.13 in.)
ISO A Series Paper Chart
ISO B Sizes of Paper
B0
1,028 mm x 1,456 mm
(40.48 in. x 57.32 in.)
B1
707 mm x 1,000 mm
(28.66 in. x 40.48 in.)
B2
514 mm x 728 mm
(20.24 in. x 28.66 in.)
B3
364 mm x 514 mm
(14.33 in. x 20.24 in.)
B4
257 mm x 364 mm
(10.12 in. x 14.33 in.)
B5
182 mm x 257 mm
(7.17 in. x 10.12 in.)
B6
128 mm x 182 mm
(5.04 in. x 7.17 in.)
ISO B Series Paper Chart
ANSI (American National Standards Institute) paper sizes are the standard US engineering drawing paper sizes.
ANSI Paper Sizes
ANSI paper sizes are listed here and classifications are referenced in the ANSI paper size charts below.
ANSI A
8.5 in. x 11 in.
(215.9 mm x 279.4 mm)
ANSI B
11 in. x 17 in.
(279.4 mm x 431.8 mm)
ANSI C
17 in. x 22 in.
(432 mm x 559 mm)
ANSI D
22 in. x 34 in.
(559 mm x 864 mm)
ANSI E
34 in. x 44 in.
(1118 mm x 864 mm)
ANSI Paper Size Chart
ARCH paper sizes are the standard US architectural drawing sizes. The illustration below shows how they ARCH paper sizes are organized.
ARCH Paper Sizes
ARCH paper standards are used mostly in the US and parts of Latin America.
Arch A
9 in. x 12 in.
(229 mm x 305 mm)
Arch B
12 in. x 18 in.
(305 mm x 457 mm)
Arch C
18 in. x 24 in.
(457 mm x 610 mm)
Arch D
24 in. x 36 in.
(610 mm x 914 mm)
Arch E
36 in. x 48 in.
(1914 mm x 1219 mm)
Arch E1
30 in. x 42 in. (not shown in the illustration)
(762 mm x 1067 mm)
Arch E2
26 in. x 38 in.
(660 mm x 965 mm)
Arch E3
27 in. x 39 in.
(686 mm x 991 mm)
There are three primary paper size standards used around the world today. The most common is the international ISO standard, used throughout most of the world, and the ANSI and ARCH standard used in North America.
These sizes are used to order various printed items such as stationery, brochures, digital copies, fliers, etc. The other FAQ items on this page show paper size charts and list their dimensions.
Questions About Sheets vs. Pages
One Sheet, Two Pages
A single sheet of paper has two sides.
Each side is considered one page. So a single sheet of paper is two pages.
One Sheet Folded is Four Pages
A sheet folded in two is a four page document. Page one is the front cover, page two is the inside front, page three is the facing page, and page four is the back cover.
Two Folded Sheets as Eight Pages
Two folded sheets that are nested together are an eight page document.
Any questions, please let us know before you send us your files!
There is often confusion about the difference between what is a sheet of paper and what is a page. They are not the same.
The way that a sheet is folded (or not folded) determines how many pages there are. For example, the booklet below has two sheets of paper that are folded in half and saddle stitched (stapled) along the fold, joining them together. This booklet contains eight pages.
Another FAQs on this page shows how the printing industry counts the number of pages in a document.
If you have questions about the number of pages in your project, Contact Us so that the job can be estimated correctly. Or call us at 818-709-1220 and we’ll figure that out for you today.
