The thickness of our cover or card stocks are measured in pt (point), and our text or thin papers are measure in lb (pound). Some of our cover stocks include 18pt Brown Kraft and 20pt Cotton which are used for products like business cards or flyers. Examples of our text stocks are 100lb Gloss Text which is typically used for brochures, and 80lb Uncoated Text which is commonly used for letterheads.
GSM (Grams per Square Meter)
GSM is an acronym that stands for grams per square meter. The calculation is simply that the weight of one square meter of the stock equals so many grams. Typically, printers will refer to the gsm when buyers are looking at the different quality levels of the paper. The higher the gsm number, the heavier and thicker the paper will be. Paper with gsm that is higher is often considered higher quality paper stocks due to it being more durable and thick, allowing images to pop on either side.
It is important to note that just because a paper is heavier, does not mean it is always the best paper for the job. You will need to consider other factors such as how many pages are going to be in the final piece and whether or not the piece will ultimately mail or ship. When choosing a paper stock, knowing the gsm or at least the gsm range you are looking for, will help get you closer to the exact type of paper you are looking for.
To help you determine which gsm is best suited for your print project, it is essential to know what certain gsm weights are typically used for.
35 gsm to 55 gsm - This type of paper is considered extremely thin and almost delicate. This is the type of gsm that is used to print items such as a newspaper.
90 gsm to 100 gsm - Paper at this weight will be similar to copy paper that you will most often find in your home or at a copy center. It is best used for simple copy jobs, or jobs with less ink coverage as heavy ink coverage might still show through at this weight.
120 gsm to 140 gsm - When you get to this weight of paper you will find posters have a lot more durability. It is thick enough and heavy enough to be used for full-color flyers and to be used on posters or other types of bulletins.
210 gsm to 300 gsm - When you notice premium flyers and brochures they will often be at this weight range. You have not quite hit card thickness as the piece is still bendable easily with your fingers, but you will notice more resistance when trying to bend. This weight of paper is also most common for items such as booklet and magazine covers.
350 gsm to 400 gsm - This level of thickness is often what people may refer to a card or cover stock and is marked by its ability to stand on its own weight. You will find this thickness of paper for everything from business cards to wedding invitations.
PT, or point, is a way to calculate the thickness of a paper stock by using the caliper of the paper. Printers and paper manufacturers will measure the caliper of the paper using a micrometer. Paper caliper is determined in thousandths of an inch. This measurement is then calculated as a point, with one point being equal to one-thousandth of an inch or .001 inch. Therefore, a stock that is 10pt would measure .010 for its caliper.
This measurement is used for calculating the weight of paper for shipment, as well as the thickness to determine which machine the stock can be printed on. The higher the points, the thicker the paper. Digital machines can be rated for up to 18pt to 24pt stock, while conventional presses can run up to 40pt or even higher. Though the gsm and point thickness can vary depending on the type of stock as well as features such as finishes, you can use the below conversions as a basic rule of thumb when trying to compare the two.
3 to 6 pt. paper will come in around 60 gsm to 120 gsm - Typical for copy papers and less durable flyers.
9 pt. to 14 pt. paper will run between 199 gsm and 300 gsm - Used for posters and more durable marketing pieces.
14 pt.+ papers will usually start at about 310 gsm - Often used for the pointing of tags, header cards, and heavy covers.
Paper Weight Comparison Chart
Below is a chart that compares some of our popular stocks in varying thicknesses to GSM measurement.
|17pt Smooth Uncoated (100% Recycled)||350gsm|
|18pt Brown Kraft (100% Recycled)||315gsm|
|20pt Pulp (90% Recycled)||350gsm|
The paper term lb, also referred to as pound, is another common way in which printers will designate the type of paper they are using. To determine the weight of the paper the paper mill will weigh 500 sheets - a ream - in its original uncut size. This will give you what is known as the basis weight. As with the other terms, the higher the number, the thicker the paper. In general, bond and text papers will weigh between 20lb, and 80lb and card or cover stock can run from 65lb to 140 lb. and up.
Does being Uncoated or Coated affect the weight of paper?
When choosing the most suitable paper to print your project on, you will often have to choose whether you want to use what is referred to as uncoated paper or coated paper. Not only does each type of paper produce its own unique finishes but they are also different in terms of ink absorption.
Uncoated stocks will typically absorb the ink more, producing a more soft and muted look. This type of choice is great for those looking for an earthier feel to their printed piece. One of the cons of using uncoated paper is that you lose some of the sharpness in the detail.
Coated stocks are unocated papers with an added coating such as matte, semi gloss, matte and silk matte laminate. Coated paper is great for making details pop and can be more durable and mark less when handled.
You will notice a difference in thickness of coated paper and uncoated papers that are the same weight. During the coating process, the paper will be repeatedly smoother which will compress the fibers in the paper together, making them significantly denser. This can make coated paper feel thinner even when it is the same weight as uncoated stock.
Rigid Paper vs. Soft Paper
In paper that is rigid, bending slowly when held, such as Kraft paper, the fibers in the paper are denser which provides it with its rigid appearance and behaviour. When choosing a more rigid paper by the point method, you will measure the actual thickness based on the caliper. You would measure the same with soft papers which have thinner fibers and are more delicate such as papers that are Cotton based and often used for letterpress. Due to the rough and dense nature of rigid stocks and delicate nature of the Cotton stocks, you can have two papers with the same point thickness but that have significantly different weights. This is not only due to the density but also the material that the paper is created with as well.
Choosing the right paper may seem like a lengthy process but understanding what the different terms and designations mean is a great way to help you achieve the desired final piece you are looking for.
Related Blog Post:
Paper Weight Demystified: Pounds, Points & Grams