Scrapbooking for beginners. Part Two: Paper Weight and Applications | Magazine of the Fair of Masters

Scrapbooking for beginners. part two: paper weight and application | crafts fair magazine

And here is my next article in continuation, from the comments I realized that information about application and density, in what works and what kind of paper can be used is important.

Then again in order:

1. Office white paper
, the famous company “Snegurochka”, but there are cheaper ones, I take “SvetoCopy”, perhaps there are cheaper ones. The standard density of this paper is 80 g/m2. It is suitable for notebook sheets with both Coptic binding and ring binding, as well as simple binding with glue. Such sheets can be aged in coffee, lined, or combined with colored office paper. Colored office paper 80 g/m2 is more expensive than white.

Скрапбукинг для начинающих. Часть вторая плотность бумаги и применение, фото № 1

Some people use this kind of paper in postcards on the inside, paste congratulations in the form of a poem, etc. I don’t like to use such thin paper in cards because it makes the job easier.

Colored paper looks interesting when the notebook, for example, for a girl, is pink and the sheets of paper are the same. If the sheets are green, you can make the notebook in a botanical style, etc.

Office paper available in the following weights:

– 80 g/m2

– 90 g/m2

– 120 g/m2

– 160 g/m2

– 200 g/m2

– 220 g/m2

– 240 g/m2

These are the paper weights that are familiar to me.

The texture may also differ: glossy, matte. When choosing, you need to focus on your printer if you want to use this paper for printing. Since paper can be intended only for inkjet printing or only for laser printing. And of course, if the paper is thick, such as 200 g/m2 or more, it can also be used for backing cards, for place cards, for the base of cards, for the base of chocolate bowls, for boxes in such works as “Mom’s Treasures” and etc.

I have an inkjet printer with color inks, on it I print various illustrations, then I design a notebook with such illustrations. It really helps when you don’t have the appropriate paper, but you need a certain background for a backing or somewhere (a little) – it’s convenient to print it out.

I didn’t print out the backgrounds in large quantities, as I wrote in the previous post, they don’t replace scrap paper, and they don’t always convey the color scheme correctly.

2. Watercolor paper
, density 200 g/m2. You can also use it to make a base for postcards, boxes, chocolate boxes, paint with watercolors, and are suitable for a mixed media style. I don’t particularly know who uses it and where, I’ll describe where I use it:

– notebook endpapers, splashes of watercolor paint (color close to coffee);

Скрапбукинг для начинающих. Часть вторая плотность бумаги и применение, фото № 2

– chocolate maker;

– the basis of postcards, suitable for place cards, I classify them as postcards because the principle of creation is the same;

– decorate the boxes and then decorate the boxes with scrappaper and other decorations for scrapbooking;

– you can also make paper flowers from this paper; Astoria has very wonderful master classes. I haven’t done it myself yet, but I will definitely do it. Replaces purchased flowers, it is convenient to create flowers according to the color scheme you need. Flowers in stores are not cheap, and you always need a lot of them;

Скрапбукинг для начинающих. Часть вторая плотность бумаги и применение, фото № 3

– inserts for photos in the album in the form of a “cascade or waterfall”, this is an option, depending on the style of the photo album. My first experience was from office thin paper, but now I look – I don’t want to look;

– you can put a stamp, cut out and decorate a page or postcard or notebook, etc.;

– you can also print out the layout of the drawing on watercolor paper and color it with watercolor pencils, it turns out very beautifully;

– many printers allow you to print on this paper; in the printer settings, you need to see what paper thickness is suitable.

3. Pastel
. You can also make from it:

– base for postcards;

– inserts for photographs in the album in the form of a “cascade or waterfall”;

– boxes, in the photo a box for a flash drive made of pastel paper;

– you can also put stamp impressions, cut them out, and then use them.

4. Designer scrap paper
. It is used to make postcards, pages of photo albums, endpapers of notebooks, boxes, and anything else you like, but they probably aren’t used as pages in a writing pad, but they can be used as dividers in a notepad.

5. Cardstock
It can also be the basis of postcards; they cover boxes for flash drives and disks. It is plain, paper density 300 g/m2. I often see it used in wedding invitations. If the wedding has blue shades, then the base of the cards is blue cardstock, etc.

In fact, it’s a little difficult to cover boxes and make boxes out of it, the thickness of the paper gets in the way, but it’s possible.

6. Binding cardboard.
Used in all kinds of boxes, flash drive boxes, CD boxes, photo boxes, mom’s treasures, etc. The base is binding cardboard.

Most experts consider paper with a thickness of more than 0.2 mm or any multi-layer paper to be cardboard. There is no clear boundary between paper and cardboard. According to GOST, paper is a material with a square meter weight of up to 250 g. Accordingly, cardboard starts from 250 g/m2.

It is usually chosen by thickness.

7. Beer cardboard
.

Beer cardboard differs from binding paper in that it is whiter in color and lighter in weight with a similar sheet thickness. It got its name from its scope of application – coasters for mugs are often made from it. Beer cardboard is difficult to cut with scissors; it is better to use a modeling knife or a laser. When you try to bend it, delamination of the material may occur or a fracture of arbitrary shape may form.

In fact, I think this is a marketing ploy, so I don’t use it, I don’t like it, and it’s especially not suitable for beginners, since without special tools you’ll simply break it. Binding cardboard is better in this regard.

Beer cardboard is loose, binding cardboard is dense. I even used a bookbinding mat instead of a layout mat; it prevents the cutter from cutting through when you are cutting pages, etc. But it makes cuts, so when cutting with a cutter you can get into kinks from the cuts, the cutter will move and you will cut unevenly.

8. Kraft paper.

Density from 60 g/m2 and above. Used for pages in an album, for postcards, for backing paper, for chocolate boxes; thicker craft is used for endpapers.

Inscriptions in white and black, as well as stamps, look beautiful on this paper. There is a master Natalya Kostsova, she has wonderful craft work and color combinations.

Скрапбукинг для начинающих. Часть вторая плотность бумаги и применение, фото № 4

9. Tracing paper.

Used in photo albums, postcards, shaker cards, etc. The density of tracing paper varies from 40 to 110 g/m2. It can be colored, with a printed pattern, or embossed.

10. Binding material
. Here it is best suited for covering boxes, covers for certificates, boxes for discs and flash drives – it lies more evenly and the corners look beautiful. I haven’t used it myself yet, but I recently learned about it, so I decided to share it for those who know little about this paper. Before I found out about this paper, I tried cardstock; the corners were bad on the covers.

And probably many beginners have heard about scrapbooking machines, for which you need to buy knives, embossing folders, etc. So, these machines, of course, are very cool, they can make a miracle out of paper. Beautiful embossing, cut out beautiful monograms, frames… Therefore, the use of paper is limitless. The next article will be about the next important scrapbooking tool: glue.

Whiteness

Instrumental determination of the whiteness of materials is a technically complex task. There are too many influencing factors that have technical uncertainty. There is, for example, the problem of maintaining and checking standards, the stability of light sources – they all “age” and it is almost impossible to find two with the same characteristics, there is a problem of the sensitivity of measuring instruments when measuring paper of different colors, etc.

Measurements in the visible part of the spectrum are also affected by invisible, short-wave, ultraviolet radiation. Strictly speaking, to evaluate the optical characteristics of a material, it is necessary to determine its entire reflection spectrum. However, in practice it is more convenient to compare two numbers when comparing samples, which does not allow for comparison of continuous spectra.

  • white

    ( Brightness

    ), as the reflectivity of waves in the range of 457 nm;
  • b

    CIE quality

    ( Whitness

    ), calculated from chromaticity coordinates;
  • CIE lightness

    , defined in chromaticity coordinates L

    , a

    *
    , b

    *
    .

Standard whiteness (Brightness) of paper is the coefficient of diffuse reflection of the surface of the paper when illuminated by a specific light source, measured at a wavelength of 457 nm.

Whiteness is measured by photometers and spectrophotometers. So whiteness is measured according to the standards of different countries and according to the international standard. When measured according to GOST 30113, which coincides with the ISO 2470 standard, whiteness can exceed 100 percent.

When measuring whiteness (as with other color measurements), it is important to specify the lighting source under which the measurements are taken. As a rule, four such sources are used: “A”, “B”, “C”, “D65”. Source “A” reproduces the conditions of average artificial lighting with incandescent electric lamps, “B” – a direct sunlight lamp, “C” – a fluorescent mercury lamp, “D65” – daylight.

Since measurements using this method are carried out in a narrow range of the spectrum (about 457 nm), and the human eye sees the entire spectrum from 400 to 700 nm, the correlation with visual assessment is not always good.

CIE whiteness (Whitness), calculated from chromaticity coordinates and color coordinates (for this, the CIE-Tint value is determined). The value gives an impression of the degree of whiteness of a sample containing OOB and tint dye elements. This gives a fairly accurate correlation with the human eye and is one of the best methods for measuring whiteness.

Disadvantages of this measurement system:

  • As an official test, it can only be used to compare samples tested with the same spectrophotometer at the same time. This is due to differences in devices and light sources;
  • The sample to be measured must be sufficiently white. Newsprint, for example, gives erroneous results. The dark blue tint overestimates the CIE whiteness values.

CIE lightness, determined in conjunction with the chromaticity coordinates a* and b*. And represents the difference between black and white. For ideal white L = 100. For ideal black – 0.

As an illustration of the differences in determining the whiteness of paper depending on the method and instruments used, we present slightly processed data from a report given at the Paper Industry Technical Association (PITA) conference in Manchester in October 1997 by A. Tyndall (Clariant) ) “Production and measurement of whiteness.”

Measurements of the same paper sample were made with three spectrophotometers:

  • Elrepho 2000 using a computer program from Clariant;
  • Datacolor Spectraflash 500;
  • Minolta CM-2002

Smoothness (roughness)

The geometry of the paper surface is characterized by its smoothness or roughness.

The “surface geometry” of paper is determined not only by micro-irregularities, but also by macro-irregularities. The former are determined by microgeometry, the latter by the distribution of mass over the area.

There is a group of most common methods in which smoothness is measured using air flow.

The most common measurement methods are the Bendtsen Sheffield and Parker apparatus (roughness). Becca (smoothness).

alt
Bendtsen smoothness tester

The essence of the Beck method is to measure the time required for air of a certain volume to pass into a vacuum chamber between the surfaces of the test sample and a polished glass plate of a certain area, pressed with a certain pressure. Smoothness is measured in seconds. The higher the smoothness, the greater the value of the indicator.

There are no strict relationships between the values ​​of smoothness (roughness) indicators measured by different methods. There is a qualitative relationship between the Beck smoothness and Bendtsen roughness values.

Bendtsen and Sheffield instruments measure the flow of air passing at constant pressure between the surface of the ring and a sheet of paper.

Bendtsen roughness is expressed in ml/min, Sheffield in Sheffield units.

The figures show qualitative relationships between parameters determined by different methods. They make it possible to evaluate the nature of changes in one parameter depending on changes in another and can help in comparing the smoothness and roughness of samples measured by different methods.

The Parker method (PPS) is used to measure the roughness of paper and cardboard under conditions close to those of a printing press. The Parker roughness measurement result is expressed in microns.

Coloring and paper color

An object is perceived as luminous if its emission spectrum coincides (or overlaps) with the spectrum of visible radiation. Paper as an emitter can be considered when burning, when, depending on its composition, it emits in the red-yellow or even green-blue region, as well as when dyes are introduced into it that increase the emission of visible rays by the paper.

This becomes possible by treating paper with so-called optical brightening agents. These substances, absorbing the energy of the invisible ultraviolet sector of the spectrum, emit additional energy in the visible blue region, giving the paper the appearance of whiteness and brightness.

When light falls on a surface, it is reflected to one degree or another. The reflection of the surface of highly finished paper is partly specular, that is, an incident parallel beam of light remains parallel after reflection.

A perfectly white surface reflects all incident rays without absorbing anything. The gray surface uniformly absorbs light waves of different lengths. The light reflected from it does not change its spectral composition, only the intensity of the radiation changes.

All other surfaces reflect light at different wavelengths differently. Thus, red surfaces absorb waves in the green and blue regions of the spectrum, reflecting red ones. All technologies for producing color in production are based on the principle of selective absorption.

Strictly speaking, it is necessary to distinguish between concepts such as color and color of an object. Coloring is the ability of an object to reflect radiation with certain wavelengths, and color is the result of the implementation of this ability in certain lighting conditions.

Indeed, the white color of the paper can have a different color depending on the lighting. In addition, you need to distinguish between brightness and color. Brightness (lightness) is a quantitative characteristic of color that evaluates the amount of light radiation reflected by the surface.

Sampling

When sampling, it is necessary to follow the sequence of operations:

  • from game
    products select units
    products;
  • sheets are selected from product units
    ;
  • sample sheets (samples) are selected and cut from the selected sheets
    ;
  • in accordance with the requirements of standards for specific test methods, samples are cut
    for testing.
alt
Lorentzen & Wettre device for cutting strips for testing paper samples for tearing, breaking, and other indicators

Sheets must not have wrinkles or folds and must be flat. They must be cut from undamaged sheets of products. The edges of the selected sheets must be parallel to the machine and cross direction of the paper. The sample sheets should be approximately (300 x 450) mm in size.

When handling sample sheets, care must be taken to protect them from exposure to sunlight, liquids, changes in humidity and other undesirable influences (GOST Sampling for determining average quality).

To bring test conditions into comparable conditions, paper samples are brought to certain standard conditions for humidity and temperature before testing. And the tests themselves are carried out under these conditions. This bringing of samples to standard conditions is called conditioning.

Conditioning conditions are of three types, as indicated in the table. Conditioning conditions at 50% relative humidity are more commonly used. Special conditions are used, for example, when conditioning banknote paper.

Temperature, 0
C
Relative humidity, % Mode characteristics
23±1 50±2 Conditioning conditions for most printed papers
27±1 65±2 For tropical conditions
20±1 65±2 For special conditions

The samples are kept until they reach equilibrium moisture content, which is considered achieved if, with two successive weighings of the sample carried out after 1 hour, the last mass differs from the previous one by no more than 0.25%.

When storing and testing samples, the equilibrium humidity should not change (GOST 13523–78. Method of conditioning samples).

US Standard Paper Weight

Determining paper density by the weight of the paper package was previously widely used in the UK, Europe, as well as in North America, where it is still used. The popularity of the method in Europe fell after the international standardization of paper sizes under ISO 216 and its national predecessors in European countries.

Weight is defined as the weight of a ream of uncut paper in pounds (lb) (Note: Often, instead of pounds, reams of paper are written # after the weight number). There are many types of uncut paper that are used in various industries: for office paper and cardboard, Bond, Cover and Index are used.

So if you have a sheet of 20lb Bond Letter, it will be the same thickness as 20lb Bond Legal, although the sheets will weigh differently. But a sheet of 28lb Bond Letter sized paper will not be the same size as a 28lb Cover Letter sized paper since the uncut Bond and Cover sheets are different.

Бумага bond 20 lb
Ream of office paper bond 20 lb

The paper most commonly used in offices is 20-24 lb. Often suppliers will omit the word Bond on the packaging and simply list the weight as 20 lbs or 24 lbs, since other packaging formats always write Index or Cover unless the default Bond type has been used.

Newsprint has its own type, Newsprint, which measures 24″ x 36″ at uncut sheet size. This is significantly thicker than the untrimmed Bond and Cover types, so the most common 30lb Newsprint is actually significantly thinner than the 20lb Bond type. The next page talks about the different types of stock types of uncut sheets of paper.

Tables for converting paper weight from g/m2 to lb and vice versa.

Example: difference between cardboard and paper 300 g/m2

  • cardboard contains coarser and larger fibers than paper;
  • cardboard with the same mass per square meter is thicker – paper is no thicker than 0.25 mm, cardboard is 0.3-0.5 mm;
  • cardboard has a layered structure, the inner layers can be made from a coarse, cheaper fraction of fibers;
  • cardboard is stiffer;
  • paper contains more sizing and its surface is (almost always) smoother.
Образцы картона и бумаги
Some types of cardboard and paper

FAQ ➤ 
Difference between Kraft Paper and Kraft Cardboard

As mentioned above, the main difference is in the structure. Paper is homogeneous (with the exception of a possible surface coating – coating, for example), cardboard is multi-layered and/or contains thicker and longer fibers of cellulose and wood pulp. Therefore, cardboard of the same mass as paper will be much stiffer and stronger.

Both kraft paper and cardboard can be either ordinary, for mass consumption, or designer. Designer ones are distinguished by a more uniform structure and a “noble” external texture. Kraft paper and kraft cardboard are used in cases where it is necessary to ensure high strength and better moisture and grease protection of the packaging. Designer varieties are used to emphasize the unusualness of the product and the manufacturer’s commitment to protecting the environment – such an environmental fashion.

As you can see in the photo below, kraft cardboard sheets are more rigid than paper, the sheets hold their shape well and do not sag. When kraft cardboard is torn, a layered structure is visible, while the paper structure is homogeneous.

Tensile strength (tear resistance)

alt
Paper Tensile Strength Tester

Tensile strength is characterized by breaking force, tensile strength, tensile strength index, breaking load, breaking length and is determined according to GOST 13525.

1 “Semi-finished fibrous products, paper, cardboard. Methods for determining tensile strength and tensile elongation”, according to ISO 1924/1 “Paper and cardboard. Determination of tensile strength.” The method consists of stretching a strip of a test sample of a certain size, the ends of which are fixed in clamps, until it breaks at a constant rate of increasing the distance between the clamps.

When determining tensile strength characteristics, strips of paper 15 mm wide, standard lengths, most often 180, 150 mm, are tested on a tensile testing machine.

Breaking force is the force required to break a strip, divided by its width.

Tensile strength represents the tensile strength divided by the cross-sectional area of ​​the specimen.

The magnitude of the breaking load is the force at which the test strip breaks.

The tensile strength index is calculated as the ratio of the tensile strength to the weight of paper with an area of ​​1 m2.

Breaking length is the conventional length, expressed in meters, of a strip of paper (cardboard) that breaks under its own weight when suspended vertically at one end.

Sizes of rolls, sheets, braids

The dimensions of paper sheets (paper format) and the width of rolls are determined using a metal ruler and a metal tape measure (GOST 21102).

The width of paper and cardboard in rolls is determined by measuring the width of sheets taken from the roll.

For sizes up to 1 m, measurements are made with a metal ruler, for sizes over 1 m – with a metal tape measure.

Measurements with a ruler and tape measure are made with an accuracy of 1 mm.

Sheet and roll paper sizes are standardized.

GOST 9327 “Paper and paper products. Consumer Sizes” defines standard sheet paper sizes.

According to GOST 29314 (ISO 478), ISO 593, the following formats are established:

  • roll width: 43, 45, 64, 86, 90, 122, 128;
  • uncut sheet sizes: 90 x 128;
  • uncut sheet sizes: 86 x 122;
  • uncut sheet sizes: 64 x 90;
  • uncut sheet sizes: 61 x 86;
  • uncut sheet sizes: 45 x 64;
  • uncut sheet sizes: 43 x 61.

According to GOST ISO 217‑2021, the sheet format is designated by two sizes in millimeters. The format can also be supplemented by indicating the direction of cutting the sheet using the letters: LG and SG.

The first sheet size refers to the side perpendicular to the machine direction, the second size refers to the side parallel to the machine direction. Thus, the format of a sheet of longitudinally cut paper with dimensions of 430×610 mm is designated as 430×610 mm LG, and a cross-cut sheet is designated as 610×430 mm SG.

Slitting paper (LG) is a sheet of paper whose long side is parallel to the machine direction.

Cross Cut Paper (SG) – A sheet of paper whose short side is parallel to the machine direction.

The above is illustrated by the figure.

Production tolerances for formats are established by agreement between trading partners.

Cutting sheets of paper, i.e. the degree of mismatch between the sides when bending sheets is determined according to GOST 21102–97.

Types of A4 paper and their weight

Printer paper comes in different varieties. One is designed exclusively for printing text files, another is for illustrations and business cards, and the third is for creative presentations. There are three types of printing paper, each of which has its own characteristics.

  • Offset paper is quite popular among office workers. Offset can be used for almost any printing technique. Texts, contracts, forms and even images are printed on offset sheets (if detail and brightness are not so important). The density of offset paper can vary from 60 to 160 g/m2. The standard is 70-80 g/m2.

Features of offset paper include surface roughness to the touch, dim halftones and low price.

  • Coated paper – can be glossy or matte, with a smooth, even surface. Looks whiter due to the coated layer and is stronger than offset sheets. Sheets with a coated layer do not absorb ink during printing, making the image bright and clear. Coated paper is suitable for printing both texts and illustrations. But it costs more than offset. Density can be from 70 to 300 g/m2.
  • Designer paper is about style and beauty. More dense, textured, can have various inclusions, embossing and be of a variety of colors. The cost of designer paper is an order of magnitude higher than offset or coated paper. But it is rarely used for office needs.

Basically, in offices they use offset or coated with a density of 70-80 g/m2. This is a universal value that is suitable for most printers. If there is more, it may affect the operation of the printer, if less, the sheets will be picked up by the gripping elements in several pieces.

So, let’s summarize. Choose printer paper based on your goals (what exactly you want to print) and the technical characteristics of your printer.

  • Read the instructions for the device. The appropriate density will be indicated there. Usually it is 80 g/m2. (or 80 GSM, do not forget about this density designation).
  • For inkjet printers, paper weights from 60 g/m2 are suitable for printing documents, up to 200 g/m2 for printing business cards, brochures, booklets, etc.
  • For laser printers, choose paper with a density of 80-90 g/m2.

Tip: If you do a lot of typing in the office, pay attention to the quality of the paper. This will help save the company’s equipment and budget. The classic version of printer paper for the office is A4 format, density 80 g/m2, optimal edge evenness, 500 sheets per pack.

Advertising

05/21/2020

Recommendations for preparing a catalog layout for printing

Mandatory requirements apply to any type of printed products, be it business cards, brochures, posters, etc.:

Printers often provide clients with designs in the RGB color model that is used for monitors, but CMYK is used during printing.

As a result, when converting colors from RGB to CMYK, the difference in color between the screen and paper becomes obvious, and the image comes out duller.

Overhangs are color elements of the layout extending beyond the edge of the cropped format by 3–5 mm (depending on what type of printed products are being produced). They allow you to avoid defects during cutting of the product.

If you plan to place a lot of images (diagrams, photographs, tables) in the catalog, you need to make sure that they are of high quality. Only in this case will your advertising product be effective. When it comes to a product catalog, it would be better to use the services of a photographer.

The optimal image size suitable for catalog printing is considered to be 220–300 dpi resolution with 1:1 scaling. If they are with smaller parameters (often downloaded from the Internet), then after printing they will turn out blurry with clearly visible pixels.

Quite often, the same layout is printed in different formats (A6 for leaflets, A1 and A2 for posters). The file is sent in one format, for example, A1. When placing multiple items in one order, the prepress specialist has to scale the file to the required size.

There are situations when an order is received for a poster (A1), and after a while leaflets in A6 format are needed. In this case, the question arises as to whether the product parameters were specified correctly during ordering or whether the file was sent in the wrong format.

In this case, work cannot continue until the details are clarified, and this will require contacting the customer. On the one hand, there is nothing complicated about this, but sometimes, when the order is urgent or requires sending to another city, and you cannot reach the client by phone, you have to act immediately. Here, even a slight delay can negatively affect delivery times.

The text in the catalog should be easy to read, so you need to think carefully about and choose the font – both for the title and for the main text. If you want to use a non-standard format, then you need to do it correctly. An unusual font is only suitable for headings; it will be difficult to read in the main text.

You should also not forget about the size of the letters; they should not be too small. If there is a lot of content and it does not fit, then it would be better to increase the number of pages or the catalog format.

If there are images in the advertising printed product, they should also not be too small. If a person has to constantly squint while studying a catalog, he is unlikely to find the information he needs and will put it aside.

To test readability, you can print a few pages of the promotional product yourself using a regular printer. After reading the catalog, you will understand whether the scale of the design elements is optimal or whether something needs to be improved.

The catalog must contain an even number of pages (strips), to be more precise, a multiple of four, for example 8, 12, 16, 20, 24, etc.

Very often, misunderstandings arise between the customer and the manager regarding confusion with pages and sheets.

Each sheet consists of a front and a back, that is, two pages (strips). Thus, a brochure per staple should have a number of stripes that is a multiple of four, since when the sheet is folded in half and then stapled down the center, the result is a product with four pages (strips).

The catalog should be a single whole, and not resemble a vinaigrette. Think over the color scheme. If you have a corporate style, it is better to stick to it. If you want to make the background more diverse, you can come up with a signature pattern.

The opening page is the title page located at the beginning of the section. According to the rules, it should be located either from the beginning of the sheet, or shifted down or to the left by a maximum of 1/3 of the page.

As for the end bar, it should be at the end of the text. This can be the entire page or part of it, but not less than 1/4.

I will solve oge

Solution.

A sheet of A1 format is a rectangle with sides 84.1 cm and 59.4 cm, so its area is

S_A1=84,1 умножить на 59,4 = 4995,54 см в степени 2 .

Answer:
4995.54.

Let’s give another solution.

An A1 sheet is half an A0 sheet, so its area is half the size. Therefore, it is equal to 0.5m 2
or 5000cm 2
.

Answer:
5000.

Note by Dmitry Gushchin.

Note that the answers obtained in the first and second solutions are different. This is due to the fact that these tasks themselves are contradictory, and it is impossible to eliminate the contradiction. The fact is that the sides of the sheets of paper sizes specified in the condition must be related exactly as  корень из 2 : 1,
which is unattainable in practice. Therefore, the area of ​​a sheet of A0 paper is only approximately equal to 1 m 2
, like the area of ​​an A1 sheet, is only approximately equal to 0.5 m 2
.

In practice, the indicated contradiction between rounded answers can be easily eliminated by noting that the approximate values ​​of the lengths of the sides of sheet A1 are given in the condition with only three significant figures, which means that the answer cannot have more than three significant figures. Therefore, in the first solution, the engineer would round the product 4995.54 to 5000, where the first two zeros are significant and the last one is not. To emphasize which zeros are significant and which are not, a physicist would write the answer as 5.00 10 3
cm 2
. By the way, in the statement “the area is 1m 2
” there is only one significant figure, so in the second solution there is also only one significant figure in the number 5000. A physicist would write this (100 times less accurate than the first solution!) result in the form 5 10 3
cm 2
.

We do not know which answer the authors of the problem consider correct. In reality, there is no exact answer to the question at all, since the required area can only be found approximately. The developers of the OGE should clarify the wording of this task, for example, by giving the instruction “Give your answer in square centimeters, round to the nearest thousand.”

Surface resistance to plucking

The most important indicator of the quality of offset paper is the resistance of the surface to plucking. The determination of this indicator according to GOST 24356 “Method for determining printing properties” does not have quantitative correspondence with the standards ISO 3783 “Paper and cardboard.

Determination of plucking resistance using IGT (electric model)” and ISO 3782 “Paper and board. Determination of plucking resistance. Increasing velocity method using IGT (pendulum and spring type) apparatus.”

Among them, perhaps the most standardized instrument for determining this indicator is the instrument of IGT Testing Systems, the successor to the world famous Dutch Institute of Printing Technologies TNO – IGT.

The value of plucking resistance on this device is determined in m/s and characterizes the minimum value of the printing speed at which damage to the surface begins (violation of continuity, massive lifting of fibers or other surface elements) of the paper in the gap of the printing pair.

To have an idea of ​​the comparability of indicators, you need to know the characteristics of the resin used for printing on the proof printing machine, as well as the clamping pressure.

Instruments for assessing the printing properties of paper (they are also called proofing devices) allow for a comprehensive assessment of the printed material and printing inks – here are just a few of them: the tendency of inks to emulsify, assessment of ink transparency, paper roughness, paper tendency to the absorption of paints, assessment of the ability to print on a wet basis, the tendency of paper to dust.

Here, surface durability is assessed using the Dennison number, which corresponds to the minimum number of sticks at which the integrity of the paper surface does not break when they are separated from it.

Thickness. density. paper bulk

Measurement of density and bulk parameters is based on determining the thickness index, which is measured by thickness gauges. The thickness gauge allows you to determine the distance between the upper and lower measuring surfaces (heels) when placing paper between them.

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Thickness gauge

It should be noted that the reliability of the thickness indicator is affected by the speed and specific force of pressing the measuring heel of the device to the paper, therefore, different point measuring instruments do not give comparable values ​​of the indicator if the specific pressure on the surface of the paper in them differs.

According to GOST R 534‑2021, the thickness of paper or cardboard is determined using a thickness gauge with a division value of 10 μm or 1 μm, a contact area of ​​the measuring surfaces of 2 ± 0.1 cm2 and a force on the surface during measurement of 18.639 – 20.601 N.

Density and bulk are estimates. Density is the ratio of the mass of 1 m2 in grams to the thickness in microns (g/cm3). Plumpness is the reciprocal value, having the dimension (cm3/g).

Characteristics of sorption properties

Being a capillary-porous colloid, paper is in an unstable dynamic interaction with the surrounding moisture, absorbing or releasing water, tending to an equilibrium moisture content under given conditions.

The sorption properties of paper in relation to oil are also important to characterize its interaction with printing inks.

The property of paper is also known as hydrophobicity, which characterizes its tendency to be wetted by water. The higher the hydrophobic properties of paper, the more difficult it is to wet with water. A characteristic of short-term hydrophobicity is the paper sizing indicator.

The degree of sizing characterizes the ability of the ink to blur when writing with a fountain pen, giving so-called “whiskers” when writing a line instead of a clear edge line. The method is not used often and is replaced in paper standards by the Cobb absorption method.

To a certain extent, at a constant mass of 1 m2, hydrophobicity is assessed by the absorption of water during unilateral wetting for 20, 60 seconds or for another time on a Cobb device (GOST 12605).

The same device can also be used to determine the amount of oil absorption, but it does not correlate well with the conditions of the printing process, so to determine the amount of oil absorption it is better to use tests on the IGT proof printing machine discussed earlier.

At the same time, it should be borne in mind that for materials that do not absorb oil well, the method must be modified and the time for the disappearance of the shiny trace of a drop of oil on paper to be determined.

The tendency of paper to absorb water can be characterized by its equilibrium humidity at a certain relative humidity and ambient temperature, and which is determined by the amount of weight loss of a paper sample when dried to constant humidity (GOST 13525. 19).

When intaglio printing with toluene-based inks, the indicator of paper absorption by xylene is important, which is currently used to assess the interaction of paper in general with organic solutions (GOST 12603).