Sizes and Structure

The folder size is medium. It is 20cm in length, 16cm in width and 5cm in depth. And it is the outer size of the printed paper box.

This is a typical folding paper box with an intelligent box structure. On the sides, it has thick walls for protection and cushioning. The top cover can flip open. It has a tongue which acts as a lock for the closure of the paper box.

The advantage of the walls can also provide extra stacking ability. Then they won’t be crushed during the stacking and storage.

Materials and Paperboard

Because it is a small cardboard box, we adopt a paper material, which is very special. It is the micro-flute corrugated board. That is N flute. It is only 1mm in thickness. It is stronger than the normal 24pt SBS paperboard, because it is thicker. This leads to good rigidity and durability. Moreover, the flute height is extremely low. Thus, it has the more excellent printing quality than the E flute corrugated box, because the surface is more smoother.

Color and Printing

The printed paper box has the crisp full color printing. Most of color is navy blue with a brilliant logo. The dazzling visual effect is achieved by the gold foil stamping and embossing. On the bottom of the box is the white logo.

China BBP Co., Ltd is a leading China paper box manufacturer located in Xiamen. If you have a custom paper box to do, please do not hesitate to give us an email.

The article is written by reference to https://www.emerald.com/insight/content/doi/10.1108/00070700910992880/full/html?src=recsys

Another benefit we can get from the UV printing is the crisp image reproduced on the custom paper box. The printed paper box has the finer details and vivid colors.  Therefore, if you are looking for a custom paper box of good definition and vibrant color, the UV printing is a very good option.

For many special paperboards which have the gorgeous textures and patterns, the traditional offset printing just doesn’t work very well due to the limitation of the thickness or smoothness. However, the UV printing works. The UV printing has a less strict requirement for the paper materials. For the cosmetic paper boxes, the 24pt SBS C2S paperboard is usually used, but it is too thick for the litho printing, while the UV printing can work very well. The black special paperboard is also widely used for the custom paper boxes and UV printing can render the best printing quality.

Besides the high definition of the printing quality, the UV printing can also produce the very high glossy effect on the paper printed boxes and corrugated printed boxes. Meanwhile, the inks are prevented from fading with time.

There is another great benefit for the UV printed paper boxes. It is scratch resistant. Once the UV inks is dried by the UV light, the UV inks on the surface becomes very hard. It can well protect the custom paper box from scratching and dirt.

China BBP Co., Ltd is a custom paper box supplier located in Xiamen, China. It can produces the very high quality UV printed paper boxes and corrugated boxes. If you need a custom UV printed paper box, please contact us.

We are a small candle manufacturer in the UK about to launch a glassware range next year in the UK. We take receipt of all decorated glassware later this month and are now looking at trying to finalize the candle packaging supply.

Hoping the attached is self-explanatory. The artwork is naturally draft from a dimension perspective as it will require modification to accommodate the final paper box design and material selection. Please note the dieline template design adopted is not finalized. The current template of the printed paper box has purely been used to understand and demonstrate artwork layout and content.

The quantities would be as previously discussed. We are looking for luxury feel to the packaging and certainly open to any suggestions you may have with regard to finishes etc.

Our initial thoughts are for a clean, simple, contemporary design i.e. white (not brilliant white) with blue foiling for the front text and the horizontal band. All text on side, base and back will require to be printed in CMYK.

Let me know your thoughts and if it is something you may be interested in doing this candle paper box.

See if you are able to manufacture flat pack type paper boxes with internal liner.

We are a small candle manufacturer in the UK and looking for 3 sizes of candle and diffuser packaging.

I thought flat pack candle containers have an internal liner, the weights of the candles and diffusers are…

30cl candle – 0.7kg (700gm)
55cl candle – 1.2kg (1200gm)
100ml diffuser – 0.36kg (360gm)

Do you think the 400gsm will support all of these?

Although the packaging is to be flat pack we are keen to present a quality luxury feel to the box i.e. smooth texture white finish, blue foiling and sharp printing.

I have attached a pdf showing the dimensions of the glass containers requiring packaging plus a typical illustration of the artwork design.

Packaging Solution

We have the soft touch paper as your options. It would render a very luxury feel at the first sight, which is pure, clean and pretty. Maybe we can produce some sample boxes first if you are interested.

400gsm paperboard would work great for the candle container packaging.

For the internal liner, I suggest that we use the F flute corrugated board, white liner inside, which is 1.2mm in thickness.

With the embossing finish, letters and images of the logo raise in relief from the paperboard. Thus, the logo stands out.

Foil Stamping

While during the foil stamping process, the brilliant color on the foil paper is partly transferred to paperboard under the pressure of the engraved die, impressing a glittering logo on the paper printed box.

When Embossing and Foil Stamping Go Together

Hence, when embossing comes across foil stamping, a printed paper box starts to be under a glamour, being attractive, alluring and extravagant.

Recently we made such a custom paper box for a client from UK, which gives us an opportunity to tell our customers more details by pictures. It is a tea packaging paper box for UE COFFEE ROASTERS.

On the lid, the brand JEEVES & JERICHO has the black foil stamping first, then is embossed to have the slight 3D effect. Near the bottom of the 4 sides, the stars have only the black foil stamping.

Band Around The Body

You may notice the large white areas on the 4 sides of the body. And you think it looks ugly. Yes, it is. But it is just where the smart design is. Actually, the client has many tea flavors. It would be quite complicated to create a box design for each flavor.

We solve this problem by put a printed paper sleeve or band of each flavor around the custom paper box.

The black color corrugated board inserts usually consists of 2 types according to the thickness. One is the black color E flute insert, which is around 1.8mm in thickness and is mostly used in in the cosmetic paper boxes. The thicker paperboard can provide very good protection to keep the bottles inside safe. The other is the black color F flute insert, which is around 1mm in thickness. Besides the black color inserts, the white color corrugated inserts are widely used too.

There are 2 main concerns involved when our clients choose a black color corrugated board insert. First of all, safety of the products is the utmost concern, because bottles and plastic tubes are usually used to pack the perfumes and most cosmetic products, which is easy to break during the delivery and rough handling processes. Thus, the package needs to handled with the utmost care. Thanks to the great cushion property of the black color E flute corrugated board insert, it can greatly enhance the safety of the products inside the printed paper box during the transportation. Furthermore, the black color corrugated board inserts provide the cosmetic paper box very good rigidity inside to keep the package in good shape without being easily crushed. Therefore, the black color E flute inserts can also give the custom paper box a very good look outside to appeal the potential customers, which is the other concern of our clients.

Recently, we made a custom black paper box for a client in New Zealand. The black color corrugated board inserts are required inside the black paper box to protect the candles inside.

The candles have the heavy weight. There must be a durable package to carry the candles. The black color E flute inserts can meet this requirement perfectly. Meantime, the candles are exquisite, looking very beautiful and delicate. Thus, an attractive and desirable package is necessary. In order to give the candle paper box a luxury look, the spot UV and silver foil finish are employed, which give the custom paper box a very gorgeous look outside.

White Color E Flute Corrugated Board Insert

As A Good China corrugated box supplier and China packaging box manufacturer, in addition to the black color, China BBP Co., Ltd also supplies the white color E flute, F flute corrugated paperboard inserts, which are widely employed in the cosmetic paper boxes, for the packaging of perfume, cream, etc. The white color is put in use when the package designer attempts to communicate an impression of simplicity, cleanness and purity to the clients in the paper printed box. With the color of snow, the coolness can be felt immediately when a perfume paper box with white corrugated insert is open. 

Besides the corrugated printed boxes, cartons, the other important usage of the corrugated cardboard is used as cushion insert for many custom paper boxes.

It is divided into two categories, UV offset printing and UV varnishing. UV offset printing has the same mechanism as the conventional litho offset printing, exepting that the special formulated UV inks dries through a completely different process.

As A Good China paper box manufacturer and supplier, China BBP Co., Ltd is a China medium-sized custom paper box manufacturer and packaging solution provider with facilities around 80,000 square meters in total. The company exclusively specializes in the supply and export of the custom paper boxes, including the paper printed box, corrugated printed box, cosmetic paper box, rigid paper box, cardboard gift box and custom paper bag. If you have any questions about the custom paper box, or would like us to give you a price quote, please do not hesitate to contact us by giving us an email.

Recently we happened to make a very special E flute corrugated printed box for our client, which has the pantone silver inks printing for the background color and silver hot foil stamping for the logo text.

Pantone Silver Inks Printing

There are 2 kinds of metallic inks available for the pantone silver printing, the pantone 877C and the pantone silver 107077C.  And there is an obvious contrast between these 2 inks.

PANTONE 877 C is the silver base used to blend the ‘conventional’ PANTONE Metallic colors, which have existed since the mid-to-late 1980’s.

PANTONE Silver 10077 C is the specialized, non-leafing silver base manufactured by Eckart and used to formulate the PANTONE Premium Metallic colors, which were introduced in May 2010 with the PANTONE PLUS SERIES upgrade.

‘Conventional’ metallic base colors contain metal flake, which leafs to the surface as the ink dries to produce the metallic effect.  The extent of this ‘leafing characteristic’ can vary depending on the length of time it takes for the ink to dry.  This can lead to inconsistencies in the appearance of the colors from run to run.

Within the PANTONE Silver 10077 ink, the metallic particles are evenly dispersed within the vehicle of the ink, thereby removing this ‘leafing characteristic’ and leading to more consistently repeatable results.

Besides the metallic silver inks printing, another popuplar metallic inks printing is the metallic gold color printing, PMS 872.  They are widely used for the high-end corrugated printed boxes, paper printed boxes and rigid paper boxes.

Silver Hot Foil

Silver hot foil as well as gold hot foil is one of the most popular color for the hot foil finish, which is a speical kind of finish where paper foil is used to create striking designs and graphics on the outer surface of the packaging box. It gives the paper printed box a shiny and incredible look, adding a very luxury feel. The silver hot foil is widely used on the cosmetic paper boxes and rigid boxes.

What is 5S?

Shine or Scrub:

clean the workplace

Sort or Simplify:

seperate the useful items from the unwanted items;

get rid of the unwanted items;

Set in Order or Straighten or Systematically Arrangement:

arrange the useful items systematically so they can be easily found and selected for use

Sustain or Stabilize:

keeps sorting, shining, setting in order to sustain the clean and tidy state.

Standardize or Self-discipline:

Standardize the good practice in the first 4 steps.

It is China BBP Co., Ltd’s mission to develop the sustainable package (paper printed boxes, bags, and corrugated printed boxes) with green printing. DE is dedicated to use the latest printing technology in its various flexo and litho offset printing processes to protect the enviroment.

Reduce the Emission of Volatile Oganic Compounds

Volatile Oganic Compounds are usually abbreviated as VOCs. They are widely used as solvents in nearly all package printing processes, e.g., printing inks, press and blanket cleaning, fountain solutions, ink drying. However, the evaporation of the VOCs solvents leads to the fire accident (low flashing point), air pollution and workers health problems.

In order to reduce the VOCs emission in the paper box printing processes, DE Printed Box carries out a series of measures, for instance, using the vegetable-based soy inks to substitue the petroleum-based inks, switching to the waterless offset printing.

Alternatives to Solvent-based Inks

The convential solvent-based inks contains significant VOCs content that are derived from the petroleum distillation process. In order to reduce the solvent emissions of the petroleum-based inks, a number of alternatives are used, e.g., soy- and vegetable-based inks, water-based inks and UV/EV curable inks.

Vegetable-based Printing Inks and Soy Inks

Among the vegetable inks, the soy inks is the most popular, because the soybean oil is more stale. It is the most promising to reduce the VOCs emissions. The soybean oil acts as the vehicles of the ink pigments.

DE Printed Box uses soy inks for its litho offset printed paper boxes, bags, corrugated boxes and litho-laminated cartons. There are a number of specific advantages to use the soy inks for the litho printed paper package. For example,

• Soybean oil is safe, sustainable, renewable, recyclable and bio-degradable. And the soy inks on the paper box and litho laminated box are easier to be removed during the recycling process than the petroleum-based oil.
• Soy-based inks is more cost-effective compared with other vegetable-based inks and conventional inks, because much less soy inks are used for the same print job thanks to their more intense color.
• The soy oil has the excellent stability throughout the entire print job. They are less likely to build up on the printing plate and to skin over. Much fewer adjustments are required by the offset press operator due to the variation.
• Higher printing quality. Soy oils tend to be clearer than petroleum oils, so the colors can be brighter, richer and more vivid.

Sources:

Printing Inks

Benefits of soy-based inks

Reducing VOC solvent use in the Printing Industry

ENVIRONMENTAL IMPACT OF PRINTING INKS

China BBP Co., Ltd is a China medium-sized custom paper box manufacturer and packaging solution provider with facilities around 80,000 square meters in total. The company exclusively specializes in the supply and export of the custom paper boxes, including the paper printed box, corrugated printed box, cosmetic paper box, rigid paper box, cardboard gift box and custom paper bag. If you have any questions about the custom paper box, or would like us to give you a price quote, please do not hesitate to contact us by giving us an email.

In the traditional Offset printing process of custom paper box, the print design is output to the photographic film first, then the printing plate(mainly PS plate) is made. Therefore, this imaging technology is also referred to as CTF, computer to film. However, things are quite different now. In the modern printing facility, the artwork, usually in the PDF format created by the Adobe Photoshop, Adobe Illustrator, Adobe Indsign and other desktop layout applications is output directly onto the printing plate. And this tech is called CTP.

CTP Technology

CTP tech varies with the construction type of the imagesetter and the light source used to expose the plate surface. In terms of imagesetter, there are three different kinds: internal drum, external drum and flat-bed imagesetters. And the light used to expose the printing plate are mainly ultraviolet light lamps and laser diodes. The wavelength and energy of the laser diodes depend on used plate types.

CTP Plate Category

There are mainly 3 types: Photopolymer CTP plates, Silver Halogan CTP plates, and Thermal plates.

Advantages of the CTP Plate

CTP has several advantages over conventional platemaking. In CTP, one generation (transfer of film image to the printing plate) is removed from the printing process (eliminating the need for film and related developer chemicals), increasing sharpness and detail. CTP avoids potential losses in quality that may occur during film processing, including scratches in the film, and variations in the exposure. An imagesetter usually has an accuracy rate of +/-2%. Plates are produced in less time, are more consistent, and at a lower cost. CTP can also improve registration and image-to-edge repeatability over traditional methods.

In CTP, the media is registered (held in precise position) in the platesetter during imaging, and does not rely on a separately-aligned pin grid, as is the case with film. Defects due to dust, scratches or other artifacts are minimized.

CTP systems can significantly increase plate production outputs. Platesetters for newspaper production can output up to 300 12-inch (300 mm) plates per hour at 1270 DPI (dots per inch), whilst for commercial applications a CTP system could output 60 B1 plates at 2400 DPI for higher screen rulings.

Small portrait presses that typically create 1 or 2 color output can use anything from a standard laser printer, for low quality/low volume, up to a higher-end dedicated platesetter for higher quality and volume.

Disadvantage of the CTP Plate

Restricted to digital format. CTP productions require that the basis for the printed matter as well as the imposition, be digital.

Remaking of plates. If for some reason a CTP plate is damaged, if an error occurs when it’s ripped or if something has to be corrected after the plate is exposed, a completely new, imposed plate must be created

The CTP Tech in Bagboxprint

Bagboxprint uses the latest Computer to Plate technology, saving both time and money and improving print quality.

Faster Production Cycles CTP eliminates steps from the production cycle. Even in a Computer to Film (CTF) workflow it can take five steps from having the copy in digital form to having it imaged on a plate. In a CTP process four of these steps are fully removed. Each step eliminated from the process reduces the overall time required to get plates to press, getting the job to you more quickly.

Lower Printing Costs CTP eliminates the need for film by imaging the page directly from the computer to the printing plate, which, shortens production cycles and can save on material costs ultimately saving you money.

Sharper Print Quality CTP allows printing presses to print cleaner and crisper images by way of eliminating dot gain in the prepress process. In a CTP workflow, first generation dots are imaged to the plate eliminating dot gain in prepress. This gives the press more capacity for printing higher ink densities resulting in richer, better saturated colours.

Better Registration CTP excludes the use of film negatives or positives. CTP plates are imaged on highly accurate plate setting equipment on aluminium substrates that are very resistant to changes in temperature and humidity. Even imposed computer to film workflows cannot offer the accuracy and stability of registration that a CTP system can provide.

China BBP Co., Ltd is a China medium-sized custom paper box manufacturer and packaging solution provider with facilities around 80,000 square meters in total. The company exclusively specializes in the supply and export of the custom paper boxes, including the paper printed box, corrugated printed box, cosmetic paper box, rigid paper box, cardboard gift box and custom paper bag. If you have any questions about the custom paper box, or would like us to give you a price quote, please do not hesitate to contact us by giving us an email.

1. Native file format — acceptable print format for printers

When preparing pages for printing, the graphic designers generally use page layout programs to provide the structure and design for the job. Page layout files include the overall page design elements (rules, columns, screen tints, and so on) as well as text. These files, also known as native files, vary in format from one program to another and generally do not contain photo or illustration files. Instead, graphic files are linked to the page layout file. In addition, page layout files do not contain the fonts used to display and output the typefaces used in the document. Thus, jobs delivered by the designer to the printing company or other service provider in the native format must be accompanied by both the fonts and image files. Page layout programs provide a method to “collect” or “package” the supporting files that must accompany a native page layout file in order for that file to output properly.

.psd is the native file format for the Adobe Photoshop, .ai for Illustrator, .indd for InDesign.

EPS (short for Encapsulated PostScript) is a vector format designed for printing to PostScript printers and imagesetters. It is considered the best choice of graphics format for high resolution printing of illustrations. EPS files are created and edited in illustration programs such as Adobe Illustrator or CorelDRAW.

Vector graphics are a scalable, resolution-independent format composed of individual objects or shapes. Vector images can be resized easily without loss of quality making them an ideal format for initial logo designs and illustrations to be used in multiple sizes.

2. Recommended file format (PDF)— stardard print format by SWOP

PDF/X1a is the most widely adopted, all-inclusive file format relevant to the printing industry based on the Adobe’s Acrobat PDF format. The printing layouts created in the Adobe Photoshop, Illustrator and InDesign all can be saved in the PDF format.

TIFF/IT-P1 is an internationally-accepted format accredited by the International Standards Organization and known as ISO 12639:2004. “ISO 12639:2004 specifies a media-independent means for prepress electronic data exchange using a tag image file format (TIFF). ISO 12639:2004 defines image file formats for encoding colour continuous-tone picture images, colour line-art images, high-resolution continuoustone images, monochrome continuous-tone picture images, binary picture images, binary line-art images, screened data, and images of composite final pages” (International Standards Organization, 2004).

PDF verse TIFF

Although SWOP allows designers to save files in either format, a review of the specifications pages for numerous publications reveals that the trend is toward PDF/X1a and away from TIFF/IT-P1.

3. Web image format (JPEGs, PNG, GIF) — the least wanted file format

JPG (short for Joint Photographic Experts Group, and pronounced jay-peg) is a file format best used for photo images which must be very small files, for example, for web sites or for email. JPG uses lossy compression (lossy meaning “with losses to quality”). Lossy means that some image quality is lost when the JPG data is compressed and saved, and this quality can never be recovered.

GIF (short for Graphics Interchange Format) is a file format for storing graphical images up to 256 colors. It uses a lossless compression method which makes for higher quality output.

PNG (short for Portable Network Graphics) was created as a more powerful alternative to the GIF file format. PNGs are not restricted to the 256 color limitation of GIF files and have better compression. A PNG file can be saved with a transparent background which allows you to place your image on top of another image without an outlining white box.

GIF files are probably the most popular on the web being used in logos and color images. Even though PNG files are widely supported, GIF is still the most popular.

TIFF, JPEGs and PSD

TIFFs, JPEGs and even PSDs are what you should be saving your bitmap files as (the sort of things created in Photoshop).

TIFFs and PSDs are lossless. You don’t lose any quality by saving a file as a TIFF or PSD.

JPEGs normally lose quality when you save them but take up a lot less space on your computer. A very high quality JPEG is often not a lot different to a TIFF or PSD, but it does very much depend on the sort of image you’re saving.

A TIFF or PSD is normally a better option than a JPEG. But if you’ve been supplied with a JPEG, from a camera or stock photo website, and you’re not modifying the image then you will gain nothing from saving it as a TIFF or PSD. A TIFF or PSD cannot create detail where there was none in the first place. But a JPEG can remove detail where once there was some.

There’s a couple of thing to notice in the pictures here related to JPEGs. Firstly, JPEGs can’t handle spot colours. So when this JPEG was saved it converted the Pantone colour into a CMYK value. Secondly, the white space in between the red lines on the JPEG is filled with a very subtle yellow/grey tint. This is due to the compression.

China BBP Co., Ltd is a China medium-sized custom paper box manufacturer and packaging solution provider with facilities around 80,000 square meters in total. The company exclusively specializes in the supply and export of the custom paper boxes, including the paper printed box, corrugated printed box, cosmetic paper box, rigid paper box, cardboard gift box and custom paper bag. If you have any questions about the custom paper box, or would like us to give you a price quote, please do not hesitate to contact us by giving us an email.

When we prepare the artwork of the custom paper boxes for printing, we come across a lot of jargon, like pixels, ppi, dpi, spi, lpi. In this post, we will have a full explanation for these terms. 

Reference:  http://the-print-guide.blogspot.com/2009/04/image-resolution-for-printing-lpi-vs.html

Part1: Raster Image, Pixels, Resolution, PPI, DPI, SPI

What are pixels?

When we create an image from a scanner, a phone camera or Adobe Photoshop, we get a digital raster image. It consists a mosaic of pixels. They are the basic picture elements.

Here is an original image at actual size:

Here is a close up view showing the actual pixels that form the image:

What is the physical size of an image?

We use 2 numbers to describe the physical size of an image. 

1) The number of pixels per inch/centimeter. 

2) The number of pixels in both horizontal and vertical dimensions.

Or:

1) The number of pixels per inch/centimeter.

2) The horizontal and vertical dimensions expressed in inches/centimeters.

Those are just two ways of saying the same thing. 

What is ppi?

The number of pixels per inch is ppi.

Relationship between ppi and vertical/horizontal size

Here is the original image with a dialog box showing its dimensions:

Note that as the resolution is changed (from 600 to 300 and 300 to 150 pixels per inch), only the density of the pixels changes, not the number of total pixels in the image, in this case 1412 pixels x 2028 pixels, therefore the file size remains the same. Put another way, each time the resolution in ppi is increased, or lowered, the physical image size changes but the total number of pixels forming the image (and hence the detail) remains the same.

 Are ppi, dpi and spi the same thing?

Note that I use the term “pixels per inch” – ppi.

Very often the term that is used is “dots per inch” or dpi.

Technically the terms are not interchangeable – however, in daily usage, when speaking about digital images the terms are considered as meaning the same thing.

You may sometimes hear the term “spi” – samples per inch. This refers to a scanner’s resolution – i.e. it ability to acquire an image at so many samples per inch (e.g. 300 spi).

Again, in practical usage, when speaking about digital images – ppi, dpi, and spi can be understood as meaning the same thing.

Digital cameras and resolution

Interestingly, digital cameras typically do not have a resolution assigned to them.

Instead a digital camera captures data based on the “megapixel” ability of its CCD sensor. For example, a 14.2 megapixel camera might capture an image that’s 4592 pixels by 3056 pixels, which equals 14,033,152 total pixels. When you open the file into an image-editing program a resolution must be assigned to the file. Most programs, including Photoshop, use 72 ppi as the default resolution.

Part 2: LPI For Printing

Halftone dots make the image reproduction

What is halftone screening?

Because printing presses can only lay down 100% ink or 0% ink, digital images acquired from scanners, digital cameras, or created directly in “paint” applications need to be converted into a binary (on/off) format. This is done through a process called halftone screening.

The result is that the image will be converted to dots of either 100% or 0% ink with the original tones being simulated, in this case, by the size of the dots. Bigger dots represent darker tones – smaller dots represent lighter tones:

What is lpi?

The fineness of the screen, and hence the level of detail in the original that can be preserved, is determined by how densely packed the dots are and is indirectly described by how many rows – or lines of dots are used per inch (or centimeter) to create the image. These virtual lines are highlighted in red below:

In this example the image is made up of 85 lines of dots per inch – expressed more commonly as an 85 lines per inch halftone – or more simply stated: an 85 lpi halftone image.

The key thing to remember is that although the halftone image is made up of dots – the level of detail that it can reproduce is described in terms of lpi NOT dpi.

So, original image pixel density/detail = ppi, spi, or dpi.

Halftone reproduction dot density/detail = lpi.

Of course, in order to pack more lines of dots into an inch – the smaller the dots become and hence the greater amount of image detail that is preserved.

40 lpi halftone:

100 lpi halftone:

200 lpi halftone:

It is the relationship of how densely packed the original pixels are (see part 1) compared to the frequency of lines per inch of the halftone screen dots that determines what image resolution is appropriate for its reproduction in print.

Part 3: The relationship between dpi/ppi and lpi for gray-scale images

The guiding principle for understanding what original image resolution (ppi/dpi) is needed compared to the halftone screen (lpi) that will be used is that the image pixels should always be more densely packed (ppi/dpi) than the detail resolving ability (lpi) of the halftone screen that is used.

To illustrate this principle I’ll take a section of the same image at different resolutions (ppi/dpi) and reproduce it using the same 150 lpi halftone screen:

Original 75 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is one half of the halftone screen resolution (lpi). As a result the halftone reproduces the individual pixels of the original. This visible artifact is termed “staircasing,” the “jaggies,” or “pixelation.”

Original 100 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is two thirds of the halftone screen resolution (lpi). As a result the halftone still reproduces the individual pixels of the original – but they are less visible.

Original 150 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is equal to the halftone screen resolution (lpi). As a result the halftone still reproduces the individual pixels of the original – but they are much less visible.

Original 225 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is 1.5 times greater than the halftone screen resolution (lpi). Although some original image pixels may still be visible, in general, the halftone no longer resolves the individual pixels of the original – just the tones they represent.
This minimum required original resolution can be represented by the formula: 1.5 X lpi = ppi @ 100% reproduction.

Original 300 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is twice the halftone screen resolution (lpi). As a result the halftone no longer resolves the individual pixels of the original – just the tones they represent.
This ideal required original resolution can be represented by the formula: 2 X lpi = ppi @ 100% reproduction.

Original 600 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is four times the halftone screen resolution (lpi). The image file size is about 7 times larger than the 225 ppi/dpi image but provides effectively no difference in the final reproduction.

The relationship between dpi/ppi and lpi for CMYK images

As with grayscale images, the guiding principle for understanding what original image resolution (ppi/dpi) is needed compared to the halftone screen (lpi) that will be used is that the halftone screen should not reproduce the image pixels themselves but instead the tones the pixels represent. It is worth comparing these images to their grayscale equivalents in part 3.

To illustrate this principle, I’ll take a section of an image rendered at different resolutions (ppi/dpi) that has been converted from grayscale to CMYK and reproduce it using the same 150 lpi halftone screen:

Original 75 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is one half of the halftone screen resolution (lpi). As a result the halftone reproduces the individual pixels of the original. This visible artifact is termed “staircasing,” the “jaggies,” or “pixelation.” That being said, the jaggies are less severe than we saw in the grayscale image at the same ppi/dpi. Also the numbers on the sail appear clearer. This suggests that it might be possible to use a lower image resolution for reproducing a CMYK image than can be used for a grayscale image.

Original 100 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is two thirds of the halftone screen resolution (lpi). As a result the halftone still reproduces the individual pixels of the original – but they are less visible.

Original 150 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is equal to the halftone screen resolution (lpi). Because the CMYK image is a composite of four individual halftone images it tends to lessen the visibility of the individual pixels of the original.

This minimum required original resolution for a CMYK image can be represented by the formula: lpi = ppi @ 100% reproduction.

Original 225 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is 1.5 times greater than the halftone screen resolution (lpi). The halftone no longer resolves the individual pixels of the original – just the tones they represent.

This ideal original resolution can be represented by the formula: 1.5 X lpi = ppi @ 100% reproduction.

Original 300 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is twice the halftone screen resolution (lpi). As a result the halftone no longer resolves the individual pixels of the original – just the tones they represent.

This maximum required original resolution can be represented by the formula: 2 X lpi = ppi @ 100% reproduction.

Original 600 ppi/dpi – halftone screen 150 lpi:

Here the image ppi/dpi is four times the halftone screen resolution (lpi). The image file size is about 7 times larger than the 225 ppi/dpi image but provides effectively no difference in the final reproduction.

Common image resolution requirements for daily printing works

The below table provides image resolution requirements for a variety of typical print applications:

What is AM halftone screening?

Note that this table refers to conventional “AM” halftone screening where the lpi signifies the dot density and hence the resolution of the halftone screen.

However, there is another type of halftone screen in use which does not have a traditional lpi. Instead, this type of screening organizes the halftone dots in random appearing patterns. Below are three different vendor’s offerings :

What is FM halftone screening?

This type of halftone is called “FM” or “Stochastic” screening (covered in other posts in this blog). Rather than indicating resolution according to “lpi” – the average actual dot size, specified in microns, of the screen pattern is used instead. Typical dot sizes are: 10 – 20 micron for commercial work, 20 – 25 micron for magazine work, and 35 micron for newspaper work. Because this type of screening has a higher average resolution than conventional AM screening – it’s a good idea to use images at a higher resolution to take advantage of this screening’s detail rendering capability. Typically 400 ppi/dpi for 10-20 micron FM, 300 ppi for 25 micron, and 200 ppi/dpi for 35 micron.

Image resolution “gotchas” – where things can go wrong

Whether you are targeting your images for AM or FM screening, there are at least three places where the resolution of the images may be accidently altered:

1) If the image is resized/scaled in the page layout application – it may no longer have an appropriate resolution:

2) If the image is resized/scaled when the file is converted to the PDF format – it may no longer have an appropriate resolution:

3) If the workflow of the printed paper box supplier is setup to resample incoming documents – they may no longer have an appropriate resolution. Most prepress RIPs are set, by default, to downsample incoming files to 300 ppi/dpi.

China BBP Co., Ltd

As A Good China packaging box supplier, China BBP Co., Ltd supplies the high-graphic printed paper boxes. The printing methods include the litho printing, or offset printing, flexo printing, silk screen printing and gravure printing.